McGraw-Hill Specialty Board Review Pediatrics, 2nd Edition

Chapter 2. CRITICAL CARE

CASE 6: A 5-MONTH-OLD WITH APNEA AND CYANOSIS

A 5-month-old male infant is brought to the emergency department after he “stopped breathing for approximately 20 seconds and became blue around his lips.” He began breathing again after the mother “blew in his face.” There have been no other symptoms such as upper respiratory tract illness, fever, vomiting, diarrhea, or change in eating habits. He takes approximately 28-34 ounces of formula per day as well as some solids and has always eaten well, although he often “spits up” after eating.

When you first see this child, he is somewhat irritable. His physical examination is completely normal except that there is dried blood in both of the child’s nares. His room air oxygen saturation is 98%. It has been approximately 90 minutes since the baby “turned blue,” and the mother appears to be quite frightened by these events.

The family history is remarkable for a sibling’s death during sleep 2 years ago, subsequently labeled as so-called SIDS (sudden infant death syndrome).

SELECT THE ONE BEST ANSWER

1. The screening test(s) that need to be performed emergently include(s)

(A) serum glucose and electrolytes

(B) a complete blood count (CBC) and differential

(C) an erythrocyte sedimentation rate and serum C-reactive protein (CRP) level

(D) examination of cerebrospinal fluid (CSF)

(E) a computed tomography (CT) scan of the head

2. In addition to the stat screening test performed in question number 1, the initial workup should also include

(A) a CT scan of the head, chest radiograph, and electrocardiogram (ECG)

(B) an esophageal pH probe, thyroid functions, and an EEG

(C) an echocardiogram, head CT, and thyroid function tests

(D) an abdominal radiograph, head magnetic resonance imaging (MRI), and glucose tolerance test

(E) adrenocorticotropic hormone (ACTH) stimulation test, MRI of the brain, and chest radiograph

3. Which characteristic of this event makes it an apparent life-threatening event (ALTE)?

(A) the fear it instilled in the mother

(B) the color change in the child

(C) the apnea as described

(D) B and C only

(E) A, B, and C

4. The family history of the previous sibling that died from “SIDS”

(A) raises suspicion of nonaccidental trauma

(B) is a common family history in a child with an ALTE

(C) increases the likelihood of future ALTEs in this patient

(D) indicates that an extensive workup in this patient for metabolic disease is needed

(E) B and C

5. In the emergency department, the child has normal electrolytes, coagulation profile, and CBC. What is the appropriate next intervention?

(A) the child should be discharged to home with a home monitor

(B) the child should be admitted to the hospital for a period of observation

(C) the child should be discharged with scheduled workup as an outpatient for head CT and pH probe

(D) the child should be admitted to the hospital for observation and workup including head CT, eye examination, and skeletal survey

(E) A and C

6. This child is admitted and the workup performed is negative except for posterior rib fractures on the right of ribs 9 and 10. Which is the most correct statement?

(A) the rib fractures are secondary to old birth trauma and are not relevant to the current illness

(B) the rib fractures are secondary to the resuscitation efforts of the mother in the day of admission

(C) posterior rib fractures are clear signs of prior nonaccidental trauma and should lead to a social service evaluation and police report

(D) posterior rib fractures are found in otherwise normal children and occur as a result of routine handling of an infant

(E) anterior rib fractures are clear signs of prior nonaccidental trauma and should lead to a social service evaluation and police report

7. The percentage of “SIDS” cases that is thought to be because of nonaccidental trauma is closest to

(A) 1-5%

(B) 6-20%

(C) 21-40%

(D) 41-55%

(E) 56-60%

8. In the child admitted with ALTE for whom a diagnosis is not made (idiopathic), the examination was normal on admission and remained normal in the hospital. Discharge plans from the hospital should include

(A) home monitoring until there is no apnea for 6 weeks, and weekly visits to the pediatrician

(B) home monitoring for 2 years and daily home nursing visits

(C) routine health care and no monitoring because there is no evidence that home monitoring prevents later death

(D) routine health care and home monitoring for 6 months if apnea does not recur

(E) routine health monitoring and home monitoring until the age of 1 year

9. In general, the siblings of a child with an ALTE with a negative workup and no suspicion of abuse as an etiology

(A) should receive polysomnography

(B) should be placed on a home apnea monitor if younger than 8 months old

(C) should receive immediate evaluation by an appropriate health-care provider

(D) should receive routine care by an appropriate health-care provider

(E) should receive home health visits weekly

10. In children who present with ALTE, the workup most frequently results in demonstration of

(A) no abnormality

(B) gastroesophageal (GE) reflux

(C) seizure disorder

(D) a prolonged QT syndrome

(E) electrolyte disturbances

11. Important aspects of the history of the ALTE is/are

(A) relationship to feeding

(B) respiratory effort during the event

(C) muscle tone during the event

(D) B and C only

(E) A, B, and C

12. All of the following are clinical features of an ALTE that point to a seizure except

(A) relationship to feeding

(B) muscle tone during the event

(C) rhythmic movements during the event

(D) fever at the time of the event

(E) period of decreased responsiveness after the event

13. In a child who presents with an ALTE, which of the following histories would be consistent with GE reflux as the underlying etiology?

(A) the mother reports arching of the back during the event

(B) the mother reports choking during the event

(C) the mother reports that the event happened just after feeding

(D) the mother reports frequent “spit-ups” after feeding

(E) all of the above

ANSWERS

1. (A) A seizure is a distinct possibility in a child with an ALTE. Metabolic derangements are common causes of seizures in this age group. Although hypomagnesemia may cause seizures, hypoglycemia, hypocalcemia, and hyponatremia are the 3 electrolyte disturbances most frequently associated with seizures. Therefore, it is imperative to obtain a serum glucose and electrolytes upon the child’s arrival in the emergency department.

2. (A) If the history and the initial lab work are not revealing, the evaluation should include a CT scan of the head, a chest radiograph, an ECG, and, perhaps, a lumbar puncture. Knowledge gained from a careful history of the event will direct the testing required and urgency of those tests. Detailed questioning should include the duration of the event, color change in the infant, respiratory efforts made by the child, and the intervention required for the episode to cease. Further questions should assess the child’s muscle tone, activity, the relationship of the episode to feeding, description of any episodes of emesis, choking or gasping, the presence of fever, and rhythmic movement of the extremities of the eyes. An understanding of the ambient lighting available to the observer may also be helpful. The presence of dried blood in the nose of this small child should prompt the clinician to consider the possibility that this is nonaccidental trauma. Further suspicion is suggested by the family history of SIDS. An EEG and, if available, a pH probe should be done after the urgent studies just described have been obtained. In a younger infant, intercurrent infections such as respiratory syncytial virus (RSV) should also be considered. If nonaccidental trauma is high on the list of possible etiologies, the workup for other concomitant trauma should be pursued with an ophthalmologic examination for retinal hemorrhage and a radiographic skeletal survey for occult fractures.

3. (E) An episode of ALTE in an infant is characterized by clinical symptoms that are sufficiently frightening to the caregiver, who believes the child may have experienced cardiac arrest or may die. These events generate substantial anxiety in the family and are also costly to the health-care system to evaluate fully. Although it a very common reason for admission to the hospital, the precise incidence and prevalence of ALTE in the United States are not known.

4. (A) SIDS has been defined by the National Institutes of Health as the sudden death of an infant or young child, that is “unexplained by history,” and in whom the autopsy fails to demonstrate a cause of death. The child who presents with an ALTE is no more likely to die subsequently from SIDS than are other children. However, SIDS is an important cause of death in infants. SIDS is the third leading cause of infant mortality following congenital abnormalities and disorders related to preterm gestation. The rate of SIDS in the United States has declined more than 50% in the last 20 years. The etiology of SIDS is still unknown, but dramatic decreases in the incidence of SIDS have been demonstrated across the world since warnings against prone positioning during sleep have been implemented. The peak incidence is at 3-5 months of age. Sleeping in the prone position clearly places infants at risk, as does young maternal age, low socioeconomic status, smoking in the house where the infant sleeps, and soft bedding. There is no association between apnea of prematurity and SIDS. Of note, fewer than 1% of children who have an ALTE go on to have any other event that is life challenging. The Back to Sleep campaign has made no impact on the incidence of ALTEs, further strengthening the assertion that these 2 diagnoses are not related. It is also important for the clinician to recognize that SIDS is not a familial event. Therefore, SIDS that recurs in a family should strongly suggest the possibility of abuse and homicide. The presence of dried blood in the child’s nose should heighten the clinician’s suspicion for nonaccidental trauma such as suffocation.

5. (D) Nearly all infants who experience an ALTE should be hospitalized for observation and evaluation. Polysomnography may be useful in the child with a negative initial evaluation and thus no identified etiology. When an etiology is discovered for the ALTE, treatment is easier than for those infants in whom no identifiable cause is found. The family history of a child with SIDS should lead the clinician to a thorough workup for nonaccidental trauma.

6. (C) Rib fractures are not a “normal” finding in infants. Fractures are generally not identified until callus has formed and therefore would not be seen immediately following resuscitative efforts. Posterior rib fractures found on radiography of the chest are further evidence of nonaccidental trauma, specifically a shaking injury. Anterior rib fractures are rare and usually do not result from anteriorposterior compression.

7. (A) Estimates suggest that nonaccidental trauma is responsible for 1-5% of so-called SIDS cases.

8. (C) Where no explanation for the inciting event can be found, many families raise the issue of home monitoring. Evidence for home monitoring to prevent consequences from an ALTE is nonexistent. In preterm infants with apnea of prematurity, home monitoring appears to be helpful until 43 weeks postconceptional age. Home monitoring may be disruptive to the family and should not be recommended after an ALTE.

9. (D) ALTE is not thought to be familial. Siblings only require routine care. So-called “familial” ALTE or SIDS should lead one to consider nonaccidental trauma as the cause.

10. (A) The differential diagnosis is broad and includes infection, particularly RSV and meningitis, gastroesophageal reflux disease (GERD), neurologic disorders such as seizures, or nonaccidental trauma, airway abnormalities, cardiac rhythm abnormalities such as prolonged QT, metabolic abnormalities, and Munchausen syndrome by proxy. The etiology in most ALTEs remains unknown even when exhaustively evaluated.

11. (E) Knowledge gained from a careful history of the event will direct the testing required and urgency of those tests. Detailed questioning should include inquiry about the duration of the event, color change in the infant, respiratory efforts made by the child, and the intervention required for the episode to cease. Further questions should assess the child’s muscle tone, activity, the relationship to feeding, episodes of emesis, choking or gasping, the presence of fever, and rhythmic movement of the extremities or the eyes.

12. (A) A child with symptoms after eating suggests a diagnosis of GERD.

13. (E)


SUGGESTED READING

Ferrell PA, Weiner GM, Lemons JA. SIDS, ALTE, apnea, and the use of home monitors. Pediatr Rev. 2002;23(1):3-9.

Hall KL, Zalman B. Evaluation and management of apparent lifethreatening events in children. Am Fam Phys. 2005;71(12):2301-2308.

CASE 7: A 4-MONTH-OLD WITH HYPOTONIA AND A WEAK CRY

A 4-month-old female infant is brought to the emergency department for poor feeding, a weak cry, and lethargy. There have been no other symptoms: no upper respiratory tract illness, no fever, no vomiting, or diarrhea. In fact, she has not had a bowel movement in 4 days. She normally takes approximately 6-8 ounces of formula at a time, but for the last few days she seems to tire after taking only 2 ounces. During the preceding 2 weeks, she has become less active. Her mother also reports that she can no longer hold her head up without support.

Her heart rate is modestly elevated at 130 beats per minute (bpm) and the remaining vital signs are normal. She has markedly diminished muscle tone. On physical examination, she seems alert but very quiet. The anterior fontanelle is soft. There are no murmurs. Breath sounds are normal. The abdominal examination is normal. Pupils are 3 mm in size and react to light bilaterally. She has generalized weakness with diminished gag and cough reflexes, a marked head lag, and diminished deep tendon reflexes.

SELECT THE ONE BEST ANSWER

1. The most likely cause of this child’s weakness is

(A) Guillain-Barré syndrome

(B) amyotrophic lateral sclerosis

(C) polio

(D) infant botulism

(E) Werdnig-Hoffman disease

2. The investigation(s) that is/are the most likely to lead to the appropriate diagnosis is

(A) serum creatinine kinase (CK) and aldolase

(B) CT scan of the head

(C) stool studies for bacterial toxin

(D) examination of CSF

(E) a blood culture

3. An alternative diagnostic test that might be useful is

(A) EEG

(B) EMG

(C) polysomnography

(D) steady state evoked potential (SSEP)

(E) MRI of the brain

4. The clinical hallmarks of infant botulism are

(A) muscle weakness and constipation

(B) muscle weakness and hypotension

(C) muscle weakness and ptosis

(D) muscle weakness and head lag

(E) muscle weakness and fever

5. The cause of infant botulism is

(A) Clostridium botulinum bacteria

(B) Clostridium botulinum toxin

(C) Clostridium difficile bacteria

(D) Clostridium difficile toxin

(E) none of the above

6. The manner in which most infants contract botulism is

(A) ingestion of Clostridium spores in food

(B) inhalation of Clostridium spores

(C) fecal-oral contamination with Clostridium bacteria

(D) blood-borne infection with Clostridium bacteria

(E) blood-borne infection with Clostridium spores

7. Of the following, the infant most likely to have botulism is

(A) a 15-month-old who was given home-canned peaches by her grandmother

(B) a 1-month-old who was given honey-dipped pacifiers for “colic”

(C) a 3-month-old living in Philadelphia in a subdivision under construction

(D) a 9-month-old who is living in urban Chicago in public housing

(E) a 6-month-old formula-fed infant living in Miami

8. The incubation period for infant botulism is

(A) 3-5 days

(B) 7-10 days

(C) 2-4 weeks

(D) 6-8 weeks

(E) 4-6 months

9. The symptoms of botulism occur because there is

(A) generalized degeneration of the anterior horn cells in the spinal cord

(B) reversible blockade of the acetylcholine receptor at the motor end plate

(C) inflammation of the myofibrils of somatic muscle

(D) an irreversible block of the release of acetylcholine at the motor end plate

(E) demyelination of the spinal cord white matter

10. Medications that might potentiate botulism include

(A) cephalosporins

(B) nonsteroidal anti-inflammatory drugs (NSAIDs)

(C) aminoglycosides

(D) antihistamines

(E) gastrointestinal (GI) motility agents

11. Possible in-hospital issue(s) in an infant with botulism include

(A) respiratory failure

(B) autonomic instability

(C) feeding intolerance

(D) nosocomial infection

(E) all of the above

12. Which of the following findings least supports an alternative diagnosis of Werdnig-Hoffman disease in this low-tone infant?

(A) weakness

(B) wasting

(C) constipation

(D) absence of tendon reflexes

(E) none of the above

13. In Werdnig-Hoffman disease, the affected anatomic structures are

(A) the alpha motor neurons

(B) the motor end plates

(C) the muscle membranes

(D) the myelin sheaths of peripheral nerves

(E) A and D

14. In polio, the affected anatomic structures of the nervous system are

(A) the alpha motor neurons

(B) the motor end plates

(C) the muscle membranes

(D) the myelin sheaths of peripheral nerves

(E) A and D

15. In Guillain-Barré disease, the affected anatomic structures in the nervous system are

(A) the alpha motor neurons

(B) the motor end plates

(C) the muscle membranes

(D) the myelin sheaths of peripheral nerves

(E) the myofibrils

16. With pancuronium use, the affected anatomic structures in the nervous system are

(A) the alpha motor neurons

(B) the motor end plates

(C) the muscle membranes

(D) the myelin sheaths of peripheral nerves

(E) A and B

ANSWERS

1. (D) This case raises the lengthy differential diagnosis of “the floppy infant,” or hypotonia (Figure 7-1). This particular child presented with a concomitant prominent history of constipation, which may direct physicians toward a diagnosis of either infant botulism or hypothyroidism. Although endemic polio has been largely absent from the United States in the 21st century, a history of foreign travel to an endemic area might suggest the diagnosis of polio. The diagnosis of Guillain-Barré syndrome must be considered as well. In a 4-month-old, Guillain-Barré is also unusual. Although congenital or infantile hypothyroidism becomes apparent at this age, it is unlikely to be missed by newborn testing in the United States. Acquired hypothyroidism is rare in this age range. Thyroid function tests certainly should be sent and the results of the child’s newborn screening should be checked. Amyotrophic lateral sclerosis (Lou Gehrig disease) is a disease of adults. Werdnig-Hoffman, or infantile spinal muscle atrophy, is a slowly progressive disease that presents with a longer duration of symptoms.

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FIGURE 7-1. Infant botulism. The floppy-constipated baby is a classic presentation of infantile botulism. (Courtesy of the Centers for Disease Control and Prevention.)


2. (C) The diagnosis of infant botulism is largely based on significant clinical suspicion. A presumptive diagnosis must be made based on clinical presentation while confirmatory studies are pending. Once suspected, stool samples can be sent to the Centers for Disease Control and Prevention for identification of C botulinum toxin. Do remember, however, that these patients are frequently constipated, so the acquisition of that stool specimen may take some time and does not always yield positive results.

3. (B) EMG testing can be performed on infants with suspected botulism. Classic findings include decreased amplitude of compound muscle action potentials, tetanic facilitation, and the absence of post-tetanic exhaustion. These EMG findings, nonetheless, are not pathognomonic, and the EMG may be normal early in the course of the disease.

4. (A) The presentation and severity of the disease can be very variable and, for unknown reasons, it appears to be more common in breastfed babies. The initial presentation may simply involve constipation and some feeding difficulty. If left unrecognized and unsupported, the patient may progress to global hypotonia, drooling, inability to eat, and respiratory failure. Symptoms will progress for 1-3 weeks before a plateau is reached, at which time the clinical condition stabilizes for another 2-3 weeks and recovery begins. Should the child need to be hospitalized, intubated, and ventilated, the hospital stay is frequently 3-6 weeks.

5. (B) Botulism is a rare but potentially fatal neuroparalytic disease, resulting from the action of a neurotoxin synthesized by C botulinum. Seen in only 100 U.S. children each year, infant botulism is a disease that occurs in the first year of life. The presentation and severity of the disease is very variable.

6. (B) The toxin is usually acquired by ingestion of C botulinum spores followed by their germination in the GI tract (see Figure 7-2).

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FIGURE 7-2. Clostridium botulinumClostridium botulinum is a gram-positive rod that will have terminal or subterminal spores. The spores are heat resistant. (Courtesy of the Centers for Disease Control and Prevention.)


7. (C) Spores can be acquired from 1 of 2 sources in infants: exposure to contaminated soil or exposure to contaminated food. Although more widely publicized, the incidence of botulism acquired from food represents only 15-20% of cases of infant botulism. Notoriously contaminated food products are homecanned fruits and raw honey. More commonly, spores are acquired by inhalation and then swallowed (ingested) from soil with a high concentration of C botulinum spores. States with the highest soil concentrations of spores include Utah, Pennsylvania, and California.

8. (C) Once germinated, C botulinum bacteria release toxin over 2-4 weeks and symptoms begin to be noted by the family.

9. (D) Neuromuscular transmission begins at the anterior horn cell of the motor nerve in the spinal cord, which is directed at the part of the anatomy receiving the signal for muscular activity. Electrical signals are transmitted down the myelinated peripheral nerve. The myelin sheath is responsible for the rapidity of transmission of that neural impulse, not the nervous impulse itself. At the peripheral nerve ending there is release of acetylcholine into the synaptic cleft separating the peripheral nerve from the motor endplate, which is located on the muscle membrane. Acetylcholine attaches to receptors on the motor endplate causing depolarization of the muscle and muscle activity.

An abnormality of the myelin sheath can be seen, as well, in diseases of both children and adults. The most common demyelinating disorder is Landry-Guillain-Barré (LGB) syndrome. LGB is a postinfectious destruction of the myelin such that nervous transmission is significantly slowed and ultimately functionally stops. Unlike botulism, this presents most often as an ascending weakness. However, like botulism, Guillain-Barré syndrome may result in respiratory insufficiency requiring mechanical ventilation.

In some diseases, acetylcholine metabolism can be blocked or its attachment to the motor endplate can be altered. In the case of botulism, the toxin causes irreversible inhibition of the release of acetylcholine at the presynaptic nerve terminal. Complete resolution of clinical symptoms requires that new nerve terminals sprout and normal release of acetylcholine resumes.

Beyond the neuromuscular receptor lies the muscle itself. A variety of disorders affecting the myocyte might present with generalized weakness and can be classified as either a myopathy or myositis. The differential diagnosis of myopathy is beyond the scope of this discussion but is generally marked by the elevation of muscle enzymes creatine phosphokinase and aldolase, and muscle tenderness. Constipation is rare.

10. (C) When aminoglycosides are given to treat intercurrent infection, they can potentiate the muscle weakness and therefore are relatively contraindicated. Aminoglycosides and hypermagnesemia augment the symptoms of botulism by causing neuromuscular failure by presynaptic blockade of acetylcholine release.

11. (E) Treatment for infant botulism is largely supportive and includes close monitoring in an intermediate or intensive care unit setting to detect progressive respiratory insufficiency. Human-derived botulinum antitoxin, also known as botulinum immunoglobulin (BIG), should be administered as well. In a controlled trial from the University of Pennsylvania, administration of BIG decreased the need for mechanical ventilation and shortened the duration of hospitalization when compared with patients in the control group. Antibiotics are helpful only to treat nosocomial infections that arise in a hospitalized patient and do not change the course of botulism.

12. (C) Werdnig-Hoffmann disease or infantile spinal muscular atrophy can present with hypotonia in infancy. These infants would be expected to have weakness, wasting, and absence of tendon reflexes. Tongue fasciculation might also be observed. Constipation would be rare.

13. (A) The neurologic examination will lead you down the path of a myelopathy, neuropathy, or a myopathy. Nerve conduction and electromyographic studies can confirm your suspicion of the anatomic location of the pathology. In Werdnig-Hoffman, the interruption in neuromuscular transmission is at the anterior horn cell. In the adult patient, the most common disease affecting the anterior horn cell is amyotrophic lateral sclerosis (Lou Gehrig disease).

14. (A) In polio, the interruption is also at the anterior horn cell. Beyond the anterior horn cell level, a variety of neuropathies can interrupt peripheral nervous transmission. Most do not present with generalized weakness. Nor do affected patients present in the first 4 months of life.

15. (D) An abnormality of the myelin sheath can be seen as well in diseases of both children and adults. The most common demyelinating disorder is a lateral geniculate body (LGB) syndrome. Guillain-Barré syndrome is a postinfectious destruction of myelin such that nervous transmission is significantly slowed and ultimately functionally stops. Unlike botulism, this presents most often as an ascending weakness. However, like botulism, Guillain-Barré syndrome may result in respiratory insufficiency requiring mechanical ventilation.

16. (B) Normal functioning of the neuromuscular endplate may also be temporarily disrupted by medications commonly used in the operating room. Nondepolarizing muscle relaxants such as pancuronium bind reversibly to the motor endplates and prevent neuromuscular transmission for a short period of time. The reversibility of this process distinguishes it from other pathologic disease states, such as myasthenia gravis. In myasthenia, antibodies directed against the acetylcholine receptor on the motor endplate result in postsynaptic inhibition of neuromuscular transmission. This inhibition results in weakness, which worsens with repetitive stimulation of the endplate.


SUGGESTED READINGS

Bartlett JC. Infant botulism in adults. N Engl J Med. 1986;315(4):254-255.

Nelson KE. Editorial: The clinical recognition of botulism. JAMA. 1979;241(5):503-504.

L’Hommedieu CL, Polin RA. Progression of clinical signs in severe infant botulism. Clin Pediatr. 1981;20(2):90-95.

Domingo RM, Haller JS, Gruenthal M. Infant botulism: two recent cases and literature review. J Child Neurol. 2008;23(11):1336-1346.

Chia JK, Clark JB, Ryan CA, et al. Botulism in an adult associated with food-borne intestinal infection with Clostridium botulinumN Engl J Med. 1986;315(4):239-240.

CASE 8: A 5-YEAR-OLD BOY WITH FEVER, DROOLING, AND STRIDOR

A 5-year-old boy presents to the emergency department with a 12-hour history of fever and drooling. He was well previously. His temperature is 39.5° C and he appears toxic. There have been no other symptoms and no sick contacts. He is visiting his aunt in the United States and lives in Guatemala. He has received no immunizations.

On physical examination, the heart rate is 120 bpm, the respiratory rate is 26, and the room-air blood oxygen saturation is 92%. The child has marked inspiratory stridor and refuses to swallow. He is sitting, leaning forward slightly, and refuses to lie down for the examination.

A chest radiograph is normal. The leukocyte count is 28,000/mmwith a significant left shift.

SELECT THE ONE BEST ANSWER

1. What is the best initial diagnostic procedure?

(A) a radiograph of the neck

(B) an evaluation of the upper airway by an otolaryngologist

(C) ultrasonography of the neck

(D) a nasopharyngeal aspirate for culture

(E) a chest radiograph

2. In this case, if the diagnosis is epiglottitis, what is the likely pathogen?

(A) a coagulase-negative staphylococcus

(B) Streptococcus pneumoniae

(C) Haemophilus influenzae

(D) parainfluenza virus

(E) influenza virus

3. If the diagnosis of epiglottitis is confirmed in the operating room by direct visualization by an otolaryngologist, the best next step would be

(A) a transfer to the intensive care unit (ICU) with supplemental humidified oxygen

(B) an endotracheal intubation before transfer to the ICU

(C) a tracheostomy before transfer to the ICU

(D) a transfer to the ICU with administration of corticosteroids

(E) admission to the pediatric floor for intravenous (IV) antibiotics

4. In the United States, epiglottitis is best characterized as

(A) seasonal

(B) sporadic

(C) largely eradicated by immunization

(D) endemic

(E) none of the above

5. The differential diagnosis of the febrile illness described includes all of the following except

(A) bacterial tracheitis

(B) retropharyngeal abscess

(C) peritonsillar abscess

(D) maxillary sinusitis

(E) odontogenic abscess

6. In bacterial tracheitis, the most likely pathogen is

(A) Staphylococcus aureus

(B) Haemophilus influenzae

(C) Neisseria meningitidis

(D) Streptococcus pneumoniae

(E) Moraxella catarrhalis

7. In the case of a patient with peritonsillar abscess, which of the following is true?

(A) operative intervention is often needed

(B) IV antibiotics are sufficient treatment

(C) outpatient treatment with oral antibiotics is effective

(D) endotracheal intubation is required for at least a week of antibiotic therapy to avoid airway obstruction

(E) A and D

8. In a febrile toxic-appearing patient with a maxillary sinusitis and altered sensorium, management includes

(A) IV antibiotics for 1 week

(B) oral antibiotics for 3 weeks

(C) scheduled outpatient endoscopic sinus surgical drainage

(D) evaluation of CSF for possible meningitis, then a course of IV antibiotics

(E) watchful waiting

9. A true statement about differentiating croup from epiglottitis is

(A) the child with viral croup is often older than the patient with epiglottitis

(B) the child with viral croup always has a more abrupt onset of stridor than the patient with epiglottitis

(C) the child with viral croup is more likely to present in the middle of an upper respiratory infection (URI) than the patient with epiglottitis

(D) the child with viral croup cannot be distinguished from the child with epiglottitis by clinical criteria

(E) none of the above

10. The classic clinical findings of viral croup are

(A) steeple sign, inspiratory stridor, low-grade fever, URI symptoms, barking cough

(B) steeple sign, high fever, dysphagia, rash, staccato cough

(C) thumb sign, inspiratory stridor, URI, dysphagia, barking cough

(D) thumb sign, high fever, expiratory wheeze, inspiratory stridor, staccato cough

(E) no radiographic findings, expiratory wheeze, and high fever

11. Treatments for viral croup requiring supportive care in a hospital setting should include

(A) antibiotic coverage for possible superinfection

(B) humidified oxygen, racemic epinephrine, and corticosteroids

(C) oseltamivir and humidified oxygen

(D) intubation and IV antibiotics

(E) IV antibiotics for croup

12. Pick the false statement from the following

(A) all patients with viral croup must be hospitalized because of the risk of airway obstruction

(B) all patients with epiglottitis must be hospitalized because of the risk of airway obstruction

(C) all patients with epiglottitis benefit from antibiotic therapy

(D) most patients with viral croup benefit from anti-inflammatory agents

(E) B and C

13. Pick the false statement from the following

(A) patients with viral croup who have received racemic epinephrine may be discharged to home without a period of observation

(B) patients with viral croup may be sent home safely after receiving parenteral corticosteroids

(C) patients with epiglottitis respond little to racemic epinephrine and therefore it is not recommended for treatment

(D) patients with epiglottitis do not respond to corticosteroids sufficiently to warrant their use in the disease

(E) protecting the airway is of little concern in epiglottitis

14. The ominous sign(s) of impending respiratory failure in a patient with viral croup is/are

(A) expiratory wheezes and rales

(B) inspiratory stridor and crackles

(C) muffled biphasic stridor

(D) expiratory wheezes and rhonchi

(E) coughing

ANSWERS

1. (B) Making the diagnosis of epiglottitis can be difficult. A high index of suspicion by the initial evaluating physician is imperative, especially in a young child. The patient typically presents with a sudden onset of fever, sore throat, drooling, and difficulty swallowing. Classically, the child appears toxic with temperatures that can reach 39-40°C. The patient typically prefers the position of maximal airflow, sitting forward with the neck hyperextended, chin forward. An urgent referral to otolaryngology or anesthesiology is required. The patient should be taken immediately to an operating room setting and gently anesthetized. After the induction of anesthesia, an upper airway evaluation can be performed. Routine examination of the pharynx should be deferred until anesthesia is induced because sudden, complete airway obstruction might result. In this case, time spent obtaining a neck radiograph would only delay evaluation and can increase the chance of further respiratory compromise.

2. (C) Epiglottitis (in the pre-Hib vaccine era) was caused almost exclusively by Hib and usually occurred between 1 and 5 years of age with a peak incidence in the third year of life and a slight male predominance. Since the introduction of the Hib vaccine, the epidemiology of epiglottitis has shifted. In the United States, it is no longer a disease of young children but rather a disease of teenagers and young adults. In the unvaccinated patient the likely culprit may still be Hib, to which antibiotic therapy should be targeted. For patients who are vaccinated or in older patients, antibiotic therapy should cover both Hib and S aureus.

3. (B) Anatomically, epiglottitis is not limited to the epiglottis. Thus supraglottitis is a more descriptive term. It is a cellulitis of all structures of the laryngeal inlet, including the aryepiglottic folds and arytenoid cartilages. The large potential space between the epithelial layer and the cartilage in these tissues allows the accumulation of inflammatory cells and edema during infection. As this potential space enlarges, the swollen epiglottis and adjacent structures begin to obstruct airflow through the laryngeal inlet during inspiration. Abrupt onset and rapid progression of airway symptoms are the hallmarks of epiglottitis. In the operating room the diagnosis can be made by direct inspection. If confirmed, an endotracheal tube should be introduced under direct vision and secured. After securing the airway and obtaining cultures in the operating room, the patient should be transferred to the ICU where mechanical ventilation is often needed to allow the child to be adequately sedated. Reinspection of the epiglottitis using a flexible bronchoscope can be easily performed and will guide appropriate timing of the removal of the endotracheal tube. In general, 48-72 hours of antibiotic therapy is sufficient for elimination of airway obstruction. Corticosteroids have no role in epiglottitis in small children. There may be some role for corticosteroids in opportunistic infections in older patients, especially when epiglottitis is of an uncommon etiology.

4. (C) Infectious diseases of the upper respiratory tract in children are common. Inflammatory diseases involving the larynx in the first 6 years of life include croup and epiglottitis. Croup is a viral infection of the larynx, trachea, and bronchi. In contrast, epiglottitis is a bacterial disease of the larynx that has been virtually eliminated in the United States by the introduction of the Hib vaccines. Since their introduction in 1991, all diseases caused by Hib have substantially decreased, from an incidence of 100/100,000 population to 0.3/100,000 population. However, in other countries where this vaccine is not available, Hib may still be an important cause of disease.

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FIGURE 8-1. The “steeple” sign of croup in a 1-year-old (A) and a 12-year-old (B). (Reproduced, with permission, from Stone CK, Humphries RL. Current Diagnosis & Treatment: Emergency Medicine, 6th ed. New York: McGraw-Hill; 2008: Fig. 30-10A,B.)


5. (D) Diagnoses that may mimic acute epiglottitis include laryngotracheobronchitis, croup or spasmodic croup, bacterial tracheobronchitis, a foreign body lodged in the larynx or vallecula, retropharyngeal or peritonsillar abscess, and hereditary or druginduced angioedema.

Diagnosis of viral laryngotracheobronchitis is usually made on clinical grounds. The typical child with croup is about 1-6 years of age, is in the midst of a URI, has stridor and cough, and is nontoxic in appearance. Under these circumstances, confirmation of the diagnosis can be made with neck radiographs (see Figure 8-1). Narrowing of the upper airway, commonly referred to as a steeple sign, is especially apparent on the anteroposterior (AP) radiograph. In epiglottitis, a lateral neck radiograph would show an enlarged epiglottis referred to as a thumb sign (Figure 8-2), if a radiograph were obtained (see answer 1).

For children with retropharyngeal or peritonsillar abscess there may be prominent swelling and erythema of the tonsillar bed or posterior pharyngeal wall, and inspection of the mouth can be diagnostic. The clinical presentation of diphtheria can also resemble epiglottitis. However, with the widespread use of DTaP vaccination, diphtheria is rare in the US. A child with maxillary sinusitis would present with facial pain, toothache, or headache. The physical examination would reveal the presence of pain on pressure applied to the area of the sinus. The patient who has purulent pansinusitis can appear toxic but does not have airway symptoms.

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FIGURE 8-2. Epiglottitis. Lateral soft-tissue x-ray of the neck demonstrating thickening of aryepiglottic folds and thumbprint sign of epiglottis. (Reproduced, with permission, from Knoop KJ, Stack LB, Storrow AS, et al. Atlas of Emergency Medicine, 3rd ed. New York: McGraw-Hill; 2010:437. Photo contributor: Richard M. Ruddy, MD.)


6. (A) The epidemiology of epiglottitis has changed. In the United States, this is no longer a disease of young children caused by Haemophiluinfluenzae but rather a disease of teenagers and young adults. In these patients, the offending bacteriologic agent is usually S aureusStreptococcus pneumoniae, betahemolytic streptococci, nontypeable H influenzae, and even fungi have occasionally been implicated. In teens and adults with symptoms of epiglottitis, it is important to verify human immunodeficiency virus (HIV) status because opportunistic infections of the larynx are not uncommon in these patients.

7. (A) The primary cause of these deep neck infections is either S aureus or group A streptococcus. If there is concern for a diagnosis of deep neck abscess in a child, antimicrobial agents should be directed at these organisms. However, despite appropriate antibiotic therapy surgical drainage of a peritonsillar abscess is often necessary.

8. (D) Evaluation of spinal fluid in the toxic child with sinusitis is important before a course of antibiotic therapy is initiated because meningitis is not uncommon in this setting and will alter therapy. A CT scan may help localize any central nervous system (CNS) extension and is generally performed before the lumbar puncture.

9. (C) Epiglottitis is usually distinguishable from croup by the toxic appearance and the profound dysphagia seen in the child with epiglottitis. Patients with epiglottitis are 2-6 years old. Children with croup are 1-6 years of age and usually present amid an URI with prominent airway symptoms including stridor and a “barking” cough.

10. (A) Infectious croup (laryngotracheobronchitis) is most often caused by parainfluenza virus types 1 or 2. There is currently no vaccine for the parainfluenza virus, and croup remains common in the United States and all over the world. As in epiglottitis, croup affects young children. Initially patients with croup present with low-grade fever, rhinorrhea, stridor, and cough. If the disease progresses to airway obstruction, the child will have severe stridor and shortness of breath. With respiratory efforts, suprasternal retractions are also observed in children with severe croup.

11. (B) Most parainfluenza virus infections are mild with episodes of laryngotracheobronchitis lasting for 3-4 days, and treatment is largely symptomatic. Marked improvement in the duration of airway obstruction has been seen with the use of corticosteroids. Parenteral dexamethasone in a dose not exceeding 0.3 mg/kg has been recommended for severe airway obstruction. A single dose of 0.6 mg/kg may be given intramuscularly as an adjunctive therapy in severe croup. Oral dexamethasone in doses of 0.15-0.6 mg/kg lessens the severity, duration of symptoms, and need for hospitalization in patients with less severe croup. Although for many years cold mist has been recommended to treat croup, there is little evidence that this intervention is beneficial.

12. (A) Most cases of presumed viral croup can be managed as outpatients. Hospitalization is reserved for those few that are severely ill.

13. (A) Once a child has received racemic epinephrine, it is important to observe for a period of no less than 6 hours because there may be a rebound increase in airway obstruction and progressive symptoms during this time period.

14. (C) Should symptoms of croup progress to airway obstruction, there will usually be a classic series of signs demonstrated by the patient. Initially, patients with upper airway disease (extrathoracic symptoms) present with inspiratory stridor. As the extrathoracic airway obstruction progresses, both inspiratory and expiratory stridor develop. Finally as the airway narrows critically, stridor becomes quite muffled until there is little air movement at all and no sound. When patients develop biphasic stridor, respiratory failure can be anticipated and the patient should be placed in a monitored setting and aggressively treated, perhaps even intubated.

Physiologically, the airway is divided into 2 portions: an extrathoracic and an intrathoracic portion. Symptoms of airway disease depend on the location of the pathology in the airway. Epiglottitis and croup represent diseases of the extrathoracic airway. Under these conditions, airway symptoms begin on inspiration because the extrathoracic airway narrows on inhalation, whereas the intrathoracic airway will expand with the negative intrathoracic pressure generated with inhalation. Intrathoracic airway pathology, such as a vascular ring or a mediastinal tumor, presents with symptoms on exhalation. That sound heard on exhalation as a result of airway disease is frequently misconstrued as wheezing and treated as asthma when, in fact, the clinician is dealing with expiratory stridor.

Disease that compromises the intrathoracic airway causes expiratory stridor first because the intrathoracic airway is reduced in caliber during exhalation. As airway caliber is reduced to a critical level, regardless of the location, stridor will be present on inspiration and expiration (biphasic stridor) and heralds impending respiratory failure.


SUGGESTED READING

Cohen LF. Stridor and upper airway obstruction in children. Pediatr Rev. 2000;21:4-5.

Gallagher PG, Myer CM III. An approach to the diagnosis and treatment of membranous laryngotracheo-bronchitis in infants and children. Pediatr Emerg Med. 1991;7(6):337-334.

Jenkins IA, Saunders M. Infections of the airway. Paediatr Anaesth 2009;19(suppl 1):118-130.

Leipzig B, Oski FA, Cummings CW, et al. A prospective randomized study to determine the efficacy of steroids in treatment of croup. J Pediatr. 1979;94(2):194-196.

Malhotra A, Krilov LR. Viral croup. Pediatr Rev. 2001;22:5-12.

CASE 9: A 6-YEAR-OLD BOY FOUND AT THE BOTTOM OF THE NEIGHBOR’S POOL

A 6-year-old boy is brought to the emergency department by emergency medical services (EMS). He was found at the bottom of his neighbor’s swimming pool and rescued. At the scene, he was without vital signs initially. After 5 minutes of basic life support efforts, he had a cardiac rhythm and a pulse, but he was making no respiratory effort. The child was intubated and placed in a cervical collar.

On physical examination the child is unresponsive. His vital signs are blood pressure 110/56, pulse 100, respiratory rate while bagging 22, temperature 34.5°C, and oxygen saturation 100%. Auscultation of the chest reveals wheezing in the right hemithorax and coarse breath sounds throughout. The cardiac rhythm is sinus and there are no murmurs. The only other part of the physical examination that is abnormal is the neurologic examination. The child remains unresponsive to pain or voice. Pupils are 4 mm bilaterally and are very sluggish in response to light. The muscle tone is generally reduced and there is no rectal tone.

SELECT THE ONE BEST ANSWER

1. The condition of this child dictates the need for the following

(A) obtaining an AP chest film

(B) obtaining a blood sample for toxicology

(C) obtaining imaging studies of the head and cervical spine

(D) obtaining left and right lateral decubitus chest films

(E) obtaining imaging of the abdomen and pelvis

2. The clinical scenario that best predicts poor outcome in drowning is

(A) cardiopulmonary resuscitation (CPR) required at the scene of the accident

(B) CPR required in the emergency department

(C) failure to achieve spontaneous cardiac rhythm for 25 minutes

(D) submersion time longer than 5 minutes

(E) Glasgow Coma Scale score of 10 in the emergency department

3. The clinical scenario that best predicts good outcome in drowning is

(A) core temperature on arrival in the emergency department of less than 32°C

(B) return of spontaneous circulation in the emergency department

(C) responsive pupils in the emergency department

(D) continuing or resuming circulation at the accident scene

(E) a Glasgow Coma Scale score of 4 in the emergency department

4. Which of the following is the most common cause of morbidity and mortality in drowning?

(A) hypoxic encephalopathy

(B) acute hypoxic respiratory failure

(C) renal failure

(D) acute hyponatremia from water absorption

(E) B and C

5. Which of the following statements is true?

(A) saltwater drowning is more common than drowning in fresh water

(B) the lung injury that occurs in a freshwater drowning is more severe than the lung injury that occurs in salt water

(C) the clinical features of saltwater and freshwater drowning are more alike than they are different

(D) drowning results in the aspiration of large volumes of water into the tracheobronchial tree and lungs, irrespective of the type of water

(E) none of the above

6. The frequency of drowning in the United States is best described as

(A) an uncommon cause of death

(B) the second most common cause of pediatric death in many states

(C) more likely in girls irrespective of age

(D) more likely in boys younger than the age of 6, but it is of equal magnitude between the genders in older children

(E) most common in adolescent girls

7. The most important intervention that prevents accidental pool drowning is

(A) swimming lessons

(B) flotation devices

(C) fencing surrounding a pool

(D) pool covers

(E) alarms

8. On the second hospital day, the child’s examination was consistent with brain death. This diagnosis would not be possible to make by clinical examination if

(A) the child’s temperature is 35°C

(B) the child’s temperature is 36°C

(C) the patient’s phenobarbital level is 10 mg/dL or more

(D) the patient has a C1-2 fracture

(E) the patient has an L4-5 fracture

9. The definition of brain death in children requires that the child be

(A) older than 7 days of age and term at birth

(B) older than 6 months old, irrespective of gestational age

(C) older than 1 year of age, irrespective of gestational age

(D) older than 2 years of age, irrespective of gestational age

(E) older than 60 weeks’ postconceptual age

10. Confirmatory tests for brain death include all of the following except

(A) brain nuclear blood flow study

(B) MRI of the brain

(C) cerebral angiogram

(D) EEG

(E) A and C

11. Which of the following may be present and still have the patient meet brain death criteria as of 2004, according to the American Academy of Pediatrics guidelines?

(A) spinal reflexes

(B) corneal reflexes

(C) doll’s eyes (oculocephalics)

(D) pupillary response to light

(E) respiratory effort

12. Which is true about the original Harvard description of “brain death”? (Note that the terminology actually used by the Harvard group was “irreversible coma” as opposed to “brain death.”)

(A) the recommendations of the original Harvard group specified special criteria in children younger than 2 years of age

(B) the recommendations of the original Harvard group did not address brain death in children

(C) the “Harvard Criteria” required that confirmatory tests be used in all children younger than 1 year of age before declaration of death

(D) the “Harvard Criteria” for brain death required 2 EEGs to confirm brain death for children but made no such requirement for adults

(E) the “Harvard Criteria” for brain death required confirmatory tests be used in all patients regardless of age

13. The diagnosis of brain death in children as currently described by the leading societies of neurology and pediatrics requires that

(A) confirmatory tests be used in all age children before declaration of death

(B) confirmatory tests be used in all children younger than 1 year of age before declaration of death

(C) a neurologist examine all children before the declaration of brain death

(D) the declaration of brain death can be made in all children on the first physical examination consistent with brain death

(E) B and C

14. Which of the following children meet the definition of brain death?

(A) a 6-day-old with birth asphyxia who has an isoelectric EEG

(B) a 6-month-old infant found pulseless at home with agonal respirations, otherwise completely unresponsive

(C) a 2-year-old drowning victim with no brainstem function

(D) a 2-year-old trauma victim with no brainstem function, whose core temperature is 33°C

(E) a 16-year-old adolescent found unresponsive at a “Rave” party and brought to the emergency department intubated by EMS

15. Which of the following children should have confirmatory diagnostic testing in radiology before declaration of brain death because the brain death physical examination is not valid?

(A) a 3-year-old after a motor vehicle accident (MVA) with concomitant thoracic spine trauma

(B) a 6-year-old after MVA with concomitant cervical spine trauma

(C) a 7-year-old after a MVA with diffuse axonal injury

(D) a 4-year-old after a MVA who has spina bifida occulta

(E) a 10-year-old without concomitant trauma

ANSWERS

1. (C) In this case scenario, the initial physical examination was complicated by the absence of rectal tone. Once the airway has been carefully secured and hemodynamic status stabilized, this finding should direct your initial workup to urgent imaging of the head and cervical spine. Frequently, diving accidents are followed by prolonged submersion when concomitant spinal injury is involved. As with all patients who suffer traumatic accidents, coexisting injuries need to be diligently sought. Notably, especially in the elder child who suffers a submersion event, a concomitant diving injury may also be present. It is wise to image both the head and cervical spine in a victim who is unable to communicate, particularly when the accident was not witnessed. Prehospital care providers should treat patients with a drowning injury as if concomitant cervical spine trauma is present unless it is clearly observed that the patient did not dive into the body of water from which he or she was rescued. It is unlikely to have a concomitant abdominal injury in a diving injury.

Importantly, submersion injury may be the initial presentation for a child with prolonged QT syndrome, especially if the event was not witnessed. This mandates that an ECG be performed on all submersion victims when they are normothermic and their electrolytes are normal.

2. (C) The ultimate determinant of the quality of a submersion victim’s recovery is the duration of hypoxic injury. The most reliable predictors of poor outcome in the pediatric population are submersion that exceeds 10 minutes in duration, resuscitation efforts to achieve spontaneous cardiac rhythm that exceed 25 minutes, and admission to a pediatric intensive care unit with a Glasgow Coma Scale score <5 (Table 9-1). Despite this, 8-30% of children who require CPR at the scene of a drowning accident survive neurologically intact.

Prompt prehospital intervention is crucial for the injured child with a potentially reversible process. Delay in the initiation of basic and/or advanced life support in this patient population augments the hypoxic insult. A great deal of discussion has occurred regarding the routine use of the Heimlich maneuver in the prehospital care of the drowning victim. The American Red Cross continues to dissuade delaying basic life support to perform this maneuver except in the case of a patient with an airway obstruction. The presence of water in the tracheobronchial tree does not warrant the routine performance of the Heimlich maneuver, which instead may increase the quantity of regurgitated material and hamper efforts at maintaining a patent airway. There must be no delay in instituting basic and advanced life support maneuvers for the child in full arrest after a drowning.

TABLE 9-1. Glasgow Coma Scale


EYE OPENING

MOTOR RESPONSE

VERBAL RESPONSE


1. No response

1. No response

1. No response

2. Responds to pain

2. Abnormal extension (decerebrate)

2. Incomprehensible

3. Responds to voice

3. Abnormal flexion (decorticate)

3. Inappropriate

4. Spontaneous

4. Withdraws from pain

4. Confused

 

5. Localizes pain

 
 

6. Obeys verbal commands

Alternatives for young/nonverbal children:

   

1. No response

   

2. Restless, agitated

   

3. Persistently irritable

   

4. Consolable crying

   

5. Appropriate words, smiles, fixes, and follows

 

3. (D) The best predictors of a good neurologic outcome are the return of spontaneous circulation at the scene of the accident and never losing spontaneous circulation at all. Approximately 8-30% of children who require CPR at the scene of a drowning accident will survive neurologically intact. Much has been made of the circumstance of cold water submersion. Cold water locations are implicated in only 2% of all submersion deaths. Because of the protective effects of hypothermia on the brain and other vital organs, surviving a prolonged submersion is possible. It should be noted that the water needs to be cold enough to support ice on its surface for the protective effects of hypothermia to be seen. Water temperature must be less than 86°F (<30°C). Cool water does not offer the same protection. The child must cool quickly to rapidly decrease cerebral-oxygen consumption and be afforded protection by the cold. In spite of descriptions in the medical literature and lay press of dramatic recoveries from prolonged cold water submersions, these are rare. It is much more important to prevent the injury than to attempt to resuscitate the child who is already injured.

4. (A) Morbidity and mortality in drowning are largely the result of prolonged hypoxemia. Deaths that result from drowning events are largely the result of anoxic encephalopathy, that is, brain swelling, with subsequent herniation and ultimately brain death. Aspiration of water into the tracheobronchial tree causes lung injury that results in decreased lung compliance, ventilation perfusion mismatch, surfactant deactivation, and intrapulmonary shunting. These lead to a patient with continued hypoxemia, complicating the initial neurologic injury, which also largely results from hypoxemia. Prompt prehospital intervention is crucial for the injured child with a potentially reversible process. Delay in the initiation of basic and/or advanced life support in this patient population also augments the hypoxic insult. Frequently, hypoxic encephalopathy is apparent at the time of initial examination and worsens over the first 24-48 hours with progressive cerebral edema. It can be stated with reasonable certainty that for a patient who makes no improvement in the first 24-48 hours, the outcome from a drowning is almost certainly poor.

5. (C) Much has been made of the difference between drowning in salt water and drowning in fresh water. Because the submersion generally causes laryngospasm, it does not result in the aspiration of more than 3-4 mL/kg of water. Therefore, the distinction between saltwater drowning and freshwater drowning is not considered clinically important. Both types of drowning result in decreased lung compliance, increased ventilation-perfusion mismatch, surfactant deactivation, and increased intrapulmonary shunting. These lead to continued hypoxemia, complicating the initial injury, which also largely results from hypoxemia.

6. (B) Strictly speaking, drowning is defined as an immersion or submersion injury resulting in death. The term near drowning implies survival for more than 24 hours following immersion injury. Drowning is the third most common cause of accidental death in the United States. In some states with access to swimming pools, beaches, and lakes, drowning is the leading cause of death in children younger than 5 years of age. Submersion injury has a bimodal distribution of age. The first peak occurs in children younger than 5 years who are victims of unprotected backyard swimming pools. The second peak occurs in adolescents, who are victims of boating and/or swimming accidents in lakes and at beaches. These are frequently associated with alcohol or drugs and may be accompanied by spinal cord injury. In all age ranges, male victims outnumber female victims. For every child who is hospitalized following a submersion injury, at least 10 never seek medical attention and 8 others are evaluated in an emergency department and discharged. Among female children younger than 19 years of age, 1 in 3300 will drown; 1 in 1000 will be hospitalized following a water emergency. In male children younger than 19 years of age, 1 in 1100 will drown and 1 in 300 will require hospital stay for nonfatal submersion injury.

7. (C) Evidence from both epidemiologic and clinical studies suggests that the most effective means to reduce submersion injury of children should focus on prevention rather than therapy. The best method to prevent pediatric drowning is adequate supervision of a child at risk. Drowning in residential pools can be decreased substantially by the installation of complete pool fencing. This intervention has been well studied in Australia and New Zealand where pool fencing is mandated by law. To be effective, the fence must completely surround the pool with an automatic-locking gate. Should the gate be disabled or propped open, the protection of the fence is eliminated. Pool covers do not provide the same protection because they frequently collapse under the weight of a child. Swimming lessons also do not provide the same protection because a child frequently overestimates his or her ability to swim.

8. (D) It is imperative that the care provider identify any coexisting neurologic injury because it will change the course of therapy and the ability to perform a prognostic physical examination. Should the child have a cervical injury associated with submersion, the spinal cord insult will prevent the physician from assessing brainstem function by a careful neurologic examination. It will therefore be impossible to provide the family with an adequate description of the extent of neurologic insult without confirmatory testing, particularly if it is suspected that the child has progressed to brain death.

9. (A) The determination of brain death in children varies with the age of the child, and it is important to recognize there is no definition of brain death for a child who is younger than 7 days of age. The original Harvard description of irreversible coma required multiple examinations as well as an EEG.

10. (B) MRI has no role in the determination of brain death.

11. (A) The brain death examination consists of the following:

1. coma and apnea must coexist

2. there must be no evidence of brainstem function

• pupils are unreactive to light

• no eye movement in response to turning the head (doll’s eyes, oculocephalic reflex)

• no response to cold water into the ear canal (oculovestibular reflex testing)

• no movement of bulbar muscles (tested by checking for the presence of the corneal reflex, the gag reflex, coughing, suckling, or rooting)

• patient is apneic off mechanical ventilation (this assumes the patient does not have a cervical spine injury that would prevent breathing efforts even in the face of a normal functioning brainstem)

• Apnea testing needs to be performed in a fashion that guarantees the patient neither becomes hypoxemic nor hypotensive during the period of challenge. There must also be demonstration of respiratory acidosis to a pH that is 7.25 or less with concomitant absence of respiratory efforts in order to declare that the patient in fact has no respiratory brainstem function.

3. absence of hypotension or hypothermia during the examination

4. muscle tone should be flaccid and there should be no spontaneous movements and no response to central painful stimuli

5. confirmatory testing requirements are defined again by age, and no confirmatory test is required or recommended for children older than 1 year of age without other injury

The presence of deep tendon reflexes (DTR) does not preclude the diagnosis of brain death even though it is more common for them to be absent. DTRs are considered spinal reflexes, as is flexion of an extremity in response to painful stimuli applied to the distal part of that extremity. Those movements, with time, almost always vanish and do not negate the determination of brain death but can be confusing to families.

An examination for brain death by a neurologist or neurosurgeon is not required by the current societies of neurology or pediatrics, although it is recommended that a physician who is familiar with this examination be asked to evaluate the patient. This physician might be a neurologist, neurosurgeon, intensivist, neonatologist, or emergency department physician. Clearly there are local requirements, both in individual academic practices or private hospitals, that define the requirements for the declaration of brain death in each venue.

12. (B) The notion of brain death was first described by Dr. Henry K. Beecher, a neurologist from the Harvard Medical School in 1968. This concept was introduced in an effort to identify patients with irreversible coma who could be considered for an organ transplant. These criteria for irreversible coma later became the criteria for brain death determination. However, these guidelines omitted children. It was not until the mid-1980s that the issues of hypoxicischemic encephalopathy progressive to brain death and the definition of brain death in children were addressed. The diagnosis of brain death in children as currently described by the leading societies of neurology and pediatrics has specific recommendations for performing a brain death examination as well as the use of confirmatory data.

13. (B) Modern definitions of brain death in adults and children older than 1 year of age require only that the examination of the patient be consistent with brain death and that there not be confounding issues that will prevent the accuracy of that examination (as with a cervical spine injury). Multiple examinations are recommended in children younger than 1 year of age. The American Academy of Pediatrics as well as the American Society of Neurology and Neurosurgery suggest that confirmatory tests of brain function be used in these young children. For infants 7 days to 2 months of age, they recommend 2 physical examinations and 2 EEGs separated by 48 hours. Between 2 months and 1 year, 2 physical examinations and 2 EEGs separated by 24 hours are recommended. Beyond 1 year of age, physical examination alone is sufficient. It is suggested, but not required, that an observation period of at least 12 hours be used in the older child in whom 2 examinations are performed. A nuclear medicine study of cerebral blood flow or a cerebral angiogram can replace the 2 EEGs in either case.

14. (C) See answers to questions 11 and 13.

15. (B) If there is an additional injury, particularly a cervical spine injury, which interferes with the apnea test, the brain death examination is not valid. Even with intact cerebral and/or brainstem function, apnea would be present in the child with the cervical spine injury above or involving C3. Diaphragmatic paralysis and thoracic weakness are found with injury to C4 and C5, also confounding the apnea test. Therefore, one cannot do a brain death examination accurately in the presence of cervical spine trauma. A test such as a cerebral angiogram or nuclear medicine study is needed to confirm the absence of cerebral blood flow. Hypothermia, an excessive dose of barbiturates, or other metabolic intoxications also limit the accuracy of the brain death examination. Before testing, it is required that patients be normothermic with a barbiturate level sufficiently low so as not to confound the examination.


SUGGESTED READING

Ashwal S, Schneider S. Brain death in children: part I. Pediatr Neurol. 1987;3:5-11.

Lavelle JM, Shaw KN. Near drowning: is emergency department cardiopulmonary resuscitation or intensive care unit cerebral resuscitation indicated? Crit Care Med. 1993;21(3):368-373.

Liller KD, Kent EB, Arcari C, et al. Risk factors for drowning and near-drowning among children in Hillsborough County, Florida. Public Health Rep. 1993;108(3):346-353.

Meyer RJ, Theodorou AA, Berg RA. Childhood drowning. Pediatr Rev. 2006;27(5):163-168.

Quan L, Gore EJ, Wentz K, et al. Ten-year study of pediatric drownings and near-drownings in King County, Washington: lessons in injury prevention. Pediatrics. 1989;83(6):1035-1040.

Quan L, Kinder D. Pediatric submersions: prehospital predictors of outcome. Pediatrics. 1992;90(6):909-913.

Wintemute GJ, Drake C, Wright M. Immersion events in residential swimming pools. Evidence for an experience effect. Am J Dis Child. 1999;145:1200-1203.

CASE 10: A 2-YEAR-OLD BOY WITH SUDDEN ONSET OF COUGHING

A 2-year-old boy is brought to the emergency department with the sudden onset of coughing. He has not had any symptoms of upper respiratory tract illness. He has no past history of reactive airway disease, nor a family history of asthma. Before the onset of symptoms, he was playing with his older sister in the kitchen.

On physical examination the child is nontoxic but cannot stop coughing. Results of his physical examination are normal except his room air saturation is 94% and auscultation of the chest reveals wheezing in the right hemithorax and coarse breath sounds throughout.

SELECT THE ONE BEST ANSWER

1. Which of the following would be the best way to order radiographs to maximize potential for identifying the presence of a radiolucent foreign body in a cooperative child?

(A) AP and lateral chest films

(B) posteroanterior (PA) and left decubitus chest films

(C) inspiratory and expiratory films

(D) right lateral decubitus film

(E) a single view of the chest

2. If the child cannot cooperate with the requested chest X-ray (CXR), what is the next most appropriate diagnostic test?

(A) a chest CT scan

(B) a chest MRI

(C) an airway fluoroscopy

(D) a ventilation/perfusion study

(E) rigid bronchoscopy

3. This child has a normal CXR. Which of the following statements is true?

(A) a normal CXR rules out a foreign body in the airway

(B) many children with a normal CXR have had airway foreign bodies

(C) a normal CXR mandates that you proceed to a CT for diagnosis if a foreign body is suspected

(D) the CXR must be mislabeled because this child could not have a normal CXR

(E) none of the above

4. The most common aspirated airway foreign body in childhood is

(A) a peanut

(B) a marble

(C) a hot dog

(D) a balloon

(E) a coin

5. The most common airway foreign body that is lethal is

(A) a peanut

(B) a marble

(C) a penny

(D) a balloon

(E) a hot dog

6. The most common esophageal foreign body found in children is a

(A) matchstick

(B) marble

(C) penny

(D) quarter

(E) peanut

7. The most appropriate therapeutic intervention when there is a suspected tracheal foreign body in a coughing child would be

(A) urgent thoracotomy

(B) urgent upper GI

(C) urgent bronchoscopy

(D) the Heimlich maneuver

(E) emergent tracheostomy

8. If the radiograph reveals a coin in the proximal esophagus, what would the appropriate intervention be?

(A) send the child home; the coin will pass without intervention

(B) remove the coin in the emergency department using a balloon-tipped catheter

(C) schedule endoscopy in the next 12-24 hours to remove the coin

(D) push the coin into the stomach with an nasogastric tube

(E) admission to the hospital and wait for the coin to pass

9. If the radiograph reveals an aspirated watch battery, the treatment is

(A) no different from that of an aspirated coin

(B) a more urgent situation requiring more rapid endoscopy because of the risk of tissue injury

(C) a better situation for pushing the object into the stomach because it is smaller than all U.S. coins

(D) admission to the hospital and serial abdominal radiographs documenting the passage of the battery into the stool

(E) send the child home; the battery will pass without intervention

10. If a foreign body is causing near total tracheal obstruction in a child, you should first

(A) perform a blind oropharyngeal finger sweep

(B) perform a Heimlich maneuver

(C) perform an emergency tracheostomy

(D) perform a needle cricothyroidotomy

(E) A followed by B

11. The narrowest portion of a toddler’s airway is at the level of the

(A) vocal cords

(B) carina

(C) thyroid cartilage

(D) cricoid cartilage

(E) none of the above

12. The narrowest portion of a toddler’s upper GI tract is at the level of the

(A) lower esophageal sphincter

(B) pylorus

(C) cricopharyngeus muscle

(D) second portion of the duodenum

(E) carina

13. The most hazardous items, from the perspective of childhood aspiration, that can be found in a pediatrician’s office are

(A) gauze bandages

(B) ear speculums

(C) cotton balls

(D) examination gloves

(E) toys in the waiting room

14. Should an airway aspiration event be missed, it is likely to present as

(A) recurrent pneumonia

(B) wheezing

(C) chronic cough

(D) all of the above

(E) none of the above

ANSWERS

1. (C) The clinician should be suspicious for the aspiration of some kind of foreign body. Unfortunately, many foreign bodies are radiolucent. Inspiratory and expiratory films should be attempted. Hyperinflation of the lung is seen on the chest radiograph during exhalation when a foreign body is present. The alternative approach is to request both right and left lateral decubitus radiographs. In the decubitus position, there should usually be relative pulmonary volume loss. However, when in the decubitus position on the side where the foreign body has lodged, this expected volume loss will be absent.

2. (C) If the child cannot cooperate with the requested CXR or the result is not helpful, airway fluoroscopy is the next test to be performed. With airway fluoroscopy, obstruction of the airway on exhalation is frequently visible; the most common abnormality to be seen is hyperinflation of the lung segment remote from the aspiration.

3. (B) Many children who have an airway foreign body have a normal CXR. So a normal radiograph does not exclude this diagnosis.

4. (A) A variety of foreign bodies are aspirated by children. One of the most commonly aspirated materials is small food items such as a peanut.

5. (D) Lethal foreign bodies are most often balloonlike substances such as latex balloons.

6. (C) The most common esophageal foreign body in children is the penny. When left on the floor, a coin is readily available for the exploring hand and mouth of a small child. Apparently the penny is not so valuable as to encourage adults to remove them from the floor when dropped. In fact, there has been discussion among pediatric political action groups to suggest that the penny be designated a public health hazard and eliminated.

7. (C) If one suspects a tracheal or bronchial foreign body, the prudent therapeutic intervention is a trip to the operating room. A pediatric anesthesiologist and otolaryngologist should be present. The child should be anesthetized but spontaneously breathing. A flexible or rigid bronchoscope should then be introduced into the airway. The flexible bronchoscope may allow simpler visualization of the airway but is rarely sufficient to retrieve the foreign body. Introduction of a rigid bronchoscope into a small child is almost always required for the removal of the foreign body such as a peanut.

8. (C) If an esophageal foreign body is suspected, the urgency to move to the operating room is significantly decreased. An esophageal foreign body often lodges at the cricopharyngeal muscle, the narrowest portion of the esophagus. An object lodged high in the esophagus may be easily aspirated into the airway. Retrieval of esophageal foreign bodies should occur in the operating room, not in the emergency department. There is no role for the use of a balloon catheter to remove an esophageal foreign body in a child. A clinician can worsen the situation if this is attempted. With inadvertent movement of the foreign body into a position obstructing the larynx, a non–life-threatening situation changes into a lifethreatening event. When the trachea or larynx is completely obstructed, the Heimlich maneuver can be lifesaving even in a small child.

9. (B) A battery lodged within the esophagus may rapidly produce perforation with life-threatening sequelae. The current generated from the battery and mucosal surface of the esophagus produces sodium hydroxide, which leads to liquefactive necrosis of the tissue, resulting in perforation. Therefore, this situation requires urgent endoscopy for removal.

10. (B) Near or total airway obstruction should be treated with a Heimlich maneuver first in older children. In infants a combination of back blows and chest thrusts is recommended. Use of finger-sweep to remove the object from the airway may cause the object to become more deeply lodged and should not be used. If a patent airway cannot be obtained, additional life support may be necessary.

11. (D) The anatomy of the upper airway in a small child is significantly different from that of the adult. The cartilage is much less sturdy and therefore much more compressible. The airway in its entirety is smaller, with the narrowest portion at the cricoid ring until the age of 8 years. This is distinguished from the adult airway where the narrowest portion is the vocal cords. In a small child, tracheal foreign bodies are most likely lodged at the cricoid ring. This is a life-threatening emergency. An aspirated tracheal foreign body will be below the level of the vocal cords in the child, well out of sight of an examiner performing direct laryngoscopy. In an adult, a foreign body lodged in the glottis is quite visible on plain direct laryngoscopy. Should the foreign body be small enough to move through the trachea to the mainstem bronchi, either bronchus is vulnerable. Not until the child is approximately 8 years of age, when the anatomy of the airway approximates that of an adult, does the left mainstem bronchus acquire a more acute angle. The development of the aortic knob creates this angle. Therefore, in the older child and adult, an aspirated foreign body usually enters the right mainstem bronchus, whereas in childhood, either bronchus is equally possible.

12. (C) Although the narrowest portion of a child’s airway is at the level of cricoid ring, the narrowest portion of the esophagus is the level of the cricopharyngeus muscle. Therefore, it is not unusual to find an esophageal foreign body fairly high in the esophagus. When a large esophageal foreign body is lodged at the level of the cricopharyngeus, significant airway compression can occur and airway symptoms may accompany dysphagia. A high esophageal foreign body is quite vulnerable to aspiration should an inappropriate attempt be made to remove that foreign body with a balloon-tipped catheter.

13. (D) A latex glove that has been inflated to assume the character of a balloon may be easily broken and aspirated, an event that can be lethal.

14. (D) Aspiration of foreign bodies by children remains a significant problem in the 21st century. Although deaths by aspiration have decreased significantly since legislation has mandated the labeling of toys appropriate for age, mechanical suffocation still accounts for 5% of all unintentional deaths among children in the United States. Almost without exception, the clinical history of a child with foreign body aspiration is marked by an acute choking episode followed by coughing, wheezing, and stridor.

Acquisition of this history mandates the clinician to pursue the possibility of a foreign body aspiration. The child frequently presents with cough and tachypnea with diminished breath sounds, wheezing, stridor, shortness of breath, and retractions. The acute onset of wheezing is the signature of an intrathoracic airway obstruction. The symptoms associated with the foreign body often hint at its location. If the aspirated foreign body is extrathoracic, stridor will predominate; if it is intrathoracic, wheezing will predominate. Once the airway has been significantly compromised, biphasic stridor will be apparent. Of note, an esophageal foreign body can also present with stridor because of compression of the extrathoracic airway. Pneumothorax and esophageal perforation have been reported with esophageal foreign body aspiration. The high likelihood of significant complications combined with the relative low morbidity and mortality associated with an intraoperative examination of the upper airway and upper esophagus mandates that the clinician proceed to the operating room when there is a strong suspicion of an aspirated foreign body. A rate of 10-15% for negative bronchoscopy and esophagoscopy is acceptable when compared with the risk of missing an aspirated foreign body and the consequences of recurrent pneumonia, bronchiectasis, and even death.


SUGGESTED READING

Hambidge SJ, Wong S. Index of suspicion. Pediatr Rev. 2002;23(3):95-100.

Harris CS, Baker SP, Smith GA, et al. Childhood asphyxiation by food. A national analysis and overview. JAMA. 1984;251(17): 2231-2235.

Rimell FL, Thome A, Stool S, et al. Characteristics of objects that cause choking in children. JAMA. 1995;274(22):1763-1766.

CASE 11: A 3-YEAR-OLD GIRL WITH HYPOXIA AND A HISTORY OF HOARSENESS

A 3-year-old girl presents to the emergency department with hypoxia and increased work of breathing. Her family has recently moved and you are seeing her for the first time. She has spastic cerebral palsy and the cognitive development of a 6-month-old. She has had regular health care and her immunizations are up to date. On presentation she clearly has a hoarse voice and a cry that her mother reports has been present since the age of 1 year. The mother also reports that her child drools continually. As a young infant she often “spit up” but that resolved by age 6 months. Other than 2 episodes of “pneumonia,” she has been healthy. Neither episode of pneumonia required hospitalization. Her previous pediatrician had reassured the family that her voice was “normal.”

On physical examination, she is small and appears chronically undernourished. Her heart rate is 120, respiratory rate 42. The temperature is 39°C. The room air oxygen saturation is 84%. The only other significant physical findings are hoarse voice, coarse bilateral breath sounds, and moderate intercostal retractions.

SELECT THE ONE BEST ANSWER

1. What is the next diagnostic procedure indicated?

(A) a throat culture

(B) CXR

(C) ultrasound of the neck

(D) nasopharyngeal aspirate for viral direct fluorescent antibody tests (DFAs)

(E) a complete blood count

2. The first therapeutic intervention appropriate for this child is

(A) supplemental oxygen

(B) albuterol nebulizer treatment

(C) IV antibiotics

(D) racemic epinephrine

(E) intubation

3. The CXR reveals a right lower lobe infiltrate. The appropriate next intervention is

(A) postural drainage

(B) bronchial lavage and culture

(C) IV clindamycin and ceftriaxone

(D) thoracentesis for culture and Gram stain

(E) discharge the patient with a prescription for oral antibiotics

4. The child deteriorates and requires endotracheal intubation. The best indicator of the need for mechanical ventilation in this patient is

(A) severe increased work of breathing

(B) abnormal blood gas analysis

(C) pulse oximeter reading of 92% on simple face mask oxygen

(D) failure of the child to respond to verbal commands

(E) C and D

5. Once on mechanical ventilation, the patient’s CXR now reveals infiltrates in all lung fields. Her oxygen requirement has also increased and the ventilator is providing 100% oxygen and a positive endexpiratory pressure (PEEP) of 5 to maintain an Osaturation of 89%. The strategy to improve oxygenation most likely to work is

(A) increase her tidal volume

(B) increase the respiratory rate

(C) increase the PEEP

(D) administer surfactant in her endotracheal tube

(E) place the child on extracorporeal membrane oxygenation (ECMO)

6. In spite of your best efforts to improve gas exchange on mechanical ventilation, the child continues to worsen. Her arterial blood gas (ABG) on 100% oxygen, PEEP 15, tidal volume 12 mL/kg is pH: 7.29, PCO2: 66, PO2: 55. The blood gas represents a

(A) metabolic alkalosis

(B) metabolic acidosis

(C) respiratory alkalosis

(D) respiratory acidosis

(E) mixed alkalosis

7. Given the clinical scenario in question 6, your next intervention is

(A) do nothing because the patient is stable

(B) turn the patient prone and see if you can wean the FIO2

(C) place prophylactic chest tubes because the risk of pneumothorax is large at a PEEP of 15

(D) perform a bronchoalveolar lavage for the removal of bronchial debris

(E) decrease the ventilator settings

8. Lung injury from a mechanical ventilator is seen most often in which situation?

(A) the use of a 0.5 FIO2

(B) delivery of a tidal volume in excess of 8 mL/kg

(C) the use of 15 cm PEEP

(D) a consistent peak airway pressure of 30 cm H2O

(E) a respiratory rate of 20

9. If conventional mechanical ventilation fails in acute hypoxic respiratory failure beyond the neonatal period, options include

(A) the oscillator

(B) the Thera vest

(C) the use of bilevel positive airway pressure (BiPAP)

(D) the use of extracorporeal COremoval

(E) none of the above

10. Adjuncts to conventional therapy for acute hypoxic respiratory failure include all of the following except

(A) nitric oxide

(B) surfactant

(C) ECMO

(D) heliox

(E) A and D

11. All cultures in this child are negative. The tracheal aspirate is positive for lipid-laden macrophages, however, leading you to a diagnosis of

(A) aspiration

(B) toxic shock syndrome

(C) viral pneumonia

(D) Mycoplasma infection

(E) parainfluenza infection

12. The history of hoarseness in this child is

(A) not relevant because it is a normal finding

(B) leads you to be more suspicious of aspiration and GERD disease

(C) makes the diagnosis of Mycoplasma infection more likely because of its indolent course

(D) is a distinct clinical entity that is most likely unrelated to the more acute event

(E) none of the above

13. After this child recovers, what, if anything, would be the next appropriate diagnostic test?

(A) a pH probe

(B) nothing because the child has now recovered from a viral illness

(C) a chest CT scan to evaluate for chronic lung disease

(D) a cardiac catheterization to evaluate pulmonary artery pressures

(E) a lower GI series

14. The residual lung dysfunction following acute hypoxic respiratory failure is

(A) exercise intolerance/reactive airway disease

(B) chronic cough

(C) increased diffusion capacity

(D) sleep-disordered breathing

(E) no residual dysfunction

15. Untreated GERD can lead to

(A) chronic obstructive lung disease

(B) esophageal dysplasia

(C) vocal cord nodules

(D) B and C

(E) all of the above

ANSWERS

1. (B) This child is in respiratory distress. A CXR is the initial procedure that needs to be done. The history illustrates a neurologically disabled child at high risk for reflux and aspiration of oral or GI flora. After the radiograph is performed, it would be reasonable to obtain viral or bacterial studies to determine an infectious etiology.

2. (A) Supplemental oxygen should be the first intervention because she has a room air Osaturation of 84%. Additional therapies may be administered after oxygen is started.

3. (C) This child presents with a history of hoarseness and respiratory distress followed by respiratory failure, likely caused by aspiration pneumonitis. Antibiotics used to treat this event should cover oral flora including gram-positive and anaerobic organisms. If this child’s respiratory failure progresses and she requires intubation, a bronchial lavage may help in the diagnosis.

4. (A) This child progressed to acute hypoxic respiratory insufficiency (AHRF), a complex diagnosis with many etiologies. The best indicator of the need for mechanical ventilation is a marked increase work of breathing. Blood gas analysis can be useful, but the need for mechanical ventilation is largely based on clinical assessment.

5. (C) While supported with mechanical ventilation, oxygenation is enhanced or improved by increasing the inspired concentration of oxygen (FIO2), the PEEP, and/or the inspiratory time. Improved ventilation, that is, enhanced removal of CO2, can be accomplished by increases in tidal volume and/or minute ventilation. This is achieved in volume mode ventilation by increasing the tidal volume, and, in pressure mode, increase ventilation by increasing peak inflation pressure. In either mode, the respiratory rate can be increased to enhance minute ventilation and COremoval.

6. (D) The blood gas presented represents a respiratory acidosis but not a profound one. To avoid the complications of mechanical ventilation, one could argue that in significant respiratory disease, permissive hypercapnia, or the acceptance of a modest elevation of PCO2 and acidosis (pH ≥ 7.25) is acceptable.

7. (B) This child requires 100% oxygen to remain relatively well-saturated in her current state. She is already on significant PEEP, but her inspiratory time could be increased. Additionally, the patient could be turned to the prone position to augment oxygenation and facilitate reduction of FIO2, if that is not possible in the supine position. One hundred percent oxygen is likely to result in oxygen toxicity and is not recommended. Generally, a PAOhigher than 50 mm Hg is acceptable and the FIOshould be reduced. If the patient has a shunt lesion, the inspired FIOwill have a lesser impact on oxygenation. It is likely that an acceptable arterial PAOcould be achieved with less inspired oxygen.

8. (B) The goal of mechanical ventilation should be gas exchange that is acceptable if not normal, especially when ventilatory support parameters accelerate to the point at which they are toxic themselves. Recent advances in the understanding of ventilatorassociated lung injury in the adult have been applied to children with significant pulmonary disease. In these children, it is important to reduce tidal volumes to 6-8 mL/kg or less, to use PEEP to reduce FIOto less than 60%, and to employ a long inspiratory time. Although AHRF is a significant cause of morbidity in the ICU, it is rarely the primary cause of mortality. In general, patients who have hypoxic respiratory failure succumb from the other failed organ system(s) that accompany this particular insult.

9. (A) When there is consolidation, areas of the lung are perfused but not ventilated. Despite exposure to 100% oxygen, venous admixture will persist in the unventilated lung. Although the patient remains relatively desaturated, the impact of FIOwill not be linear. Therefore, it is imperative to protect the patient from toxic oxygen exposure (>60% FIO2). In the patient with persistent AHRF, high-frequency oscillatory ventilation has been useful for treatment, as have nitric oxide, surfactant, and ECMO. As a substitute for conventional mechanical ventilation, the oscillator has been perhaps the most useful of these strategies. BiPAP, or noninvasive mechanical ventilation, can also be used to supply positive pressure to support patients with less severe disease.

10. (D) Heliox is a mixture of helium and oxygen. Helium is less dense than oxygen and when mixed together improves the flow characteristics of gas in patients with airway obstruction. Unfortunately, to achieve the beneficial flow characteristics, the helium must be present at 60% or more, and thus the maximum FIOis limited to 40%. A higher FIO2 is usually desired in AHRF.

11. (A) Lipid-laden macrophages discovered in her endotracheal aspirate confirm the suspicion of reflux disease and aspiration.

12. (B) This child presents to the clinician as neurologically impaired with respiratory insufficiency. Her initial evaluation should have led one to suspect GERD because hoarseness in a child is not a “normal” finding. The hoarseness could be the result of vocal cord disturbances, either physiologic or anatomic. However, a more common scenario in an impaired 3-year-old who develops persistent hoarseness is undetected GERD.

13. (A) Following recovery, this child will require a full evaluation. GERD is particularly common in infants. At 4 months of age, it is present in 50-70% of infants but typically resolves by 1 year of age. A minority of infants go on to develop other symptoms, including dysphagia, arching of the back during feedings, refusal to eat, and failure to thrive. GERD can also be a cause of ALTE, stridor, chronic cough, recurrent pneumonia, reactive airway disease, and hoarseness. In preschool children, GERD presents with intermittent vomiting and symptoms of esophagitis. In older children and adolescents, the cardinal symptom is chronic heartburn or regurgitation. Hoarseness, asthma, chronic cough, and chronic esophagitis may also occur. Significant GERD can be severe enough to waken patients from sleep, may be exacerbated by emotional stress, and usually is postprandial.

In the child with GERD, the assessment and treatment recommendations are summarized as follows:

• For the infant with recurrent vomiting, the history and physical examination are sufficient to make the diagnosis of GERD. Further testing is not necessary, particularly in children in whom growth is uninterrupted. Reassurance and thickening of feeds may be all that is necessary.

• In the neonate and infant with recurrent vomiting and poor weight gain, a comprehensive investigation for other causes of vomiting and failure to thrive is indicated. An upper GI series to rule out anatomic abnormalities that would result in vomiting and an upper GI endoscopy are recommended.

• In the child or adolescent with vomiting and heartburn, an upper GI series or upper tract endoscopy is indicated followed by lifestyle changes: for example, food restrictions, weight loss, smoking cessation. This patient may also require a trial of medication to reduce acid production.

• In children with apnea or ALTE, a pH probe is the diagnostic evaluation test of choice. In fact, at all ages, a pH probe, properly done, is the gold standard of diagnosis.

14. (A) Long-term health issues in survivors of acute hypoxic respiratory failure include poor exercise tolerance, difficulty in return to work or school, and persistent symptoms of small airway obstruction or reactive airway disease.

15. (E) Untreated GERD can lead to significant chronic obstructive lung disease, bronchiectasis, esophageal dysphasia, and, ultimately, esophageal carcinoma. Treatment of significant GERD begins with medical management: in a 2-4 week trial using Hblockers or proton pump inhibitors (PPIs). Should the medical management trial be unsuccessful or if the child suffers severely from GERD with respiratory insufficiency, surgical intervention may be necessary. The most commonly performed operation is a Nissen fundoplication, which now can be done using a laparoscopic approach with minimal perioperative risk. Restriction of the size of the lower esophageal sphincter can be done endoscopically using radiofrequency ablation (the Stretta system). This procedure is commonly performed in adults and is increasingly performed in children. It is particularly useful in the high–surgical risk child with GERD.


SUGGESTED READING

DiMarino M, Rattan S. Pathophysiology of gastroesophageal reflux disease. Resid Staff Physician. 2003;49(6):12-16..

Herbst JJ, Minton SD, Book LSL. Gastroesophageal reflex causing respiratory distress and apnea in newborn infants. J Pediatr. 1979;95(5)part 1:763-768.

Hrabovsky EE, Mullett MD. Gastroesophageal reflux and the premature infant. J Pediatr Surg. 1986;21(7):583-587.

St. Cyr JA, Ferra TB, Thompson TR, et al. Nissen fundoplication for gastroesophageal reflux in infants. J Cardiovascular Surg. 1986;92(4):661-666.

Vecchia LKD, Grosfeld JL, West KW, et al. Reoperation after Nissen fundoplication in children with gastroesophageal reflux. Ann Surg. 1997;226(3):315-323.

CASE 12: A 16-YEAR-OLD BOY WITH VERY HIGH BODY TEMPERATURE

A 16-year-old boy is brought to the emergency department by EMS with a temperature of 42°C and seizure activity. He was transferred from a surgery center at 9 am following dental extractions, for which he had received a brief general anesthetic and was in the recovery room when he became febrile and hemodynamically unstable. He has a cardiac rhythm with a pulse but is making little respiratory effort. Before his arrival he was intubated and IV access was established. He was given a dose of lorazepam before transport. The past history is remarkable for depression for which he takes phenelzine, a monoamine oxidase (MAO) inhibitor. Drug use was denied by his parents.

On physical examination the boy is unresponsive. His vital signs are blood pressure: 150/86, pulse: 140, respiratory rate: 22 (hand ventilation), temperature: 42.5°C. Auscultation of the chest reveals normal breath sounds. The rhythm is sinus tachycardia, with peaked T waves. There are no murmurs. The only other part of the physical examination that is abnormal is the neurologic examination. The boy remains unresponsive to pain or voice. His pupils are 4 mm bilaterally, symmetric, and reactive to light. Muscle tone is increased with generalized hyperreflexia and myoclonus.

SELECT THE ONE BEST ANSWER

1. The intervention least likely to be immediately useful in this setting is

(A) obtaining a complete blood count and differential

(B) obtaining blood and urine samples for toxicology

(C) obtaining an ECG

(D) obtaining a blood gas, serum electrolytes, and a serum CK level

(E) all of the above

2. The results of the blood gas are as follows: pH: 7.07, PCO2: 74, PO2: 98, base excess (BE): −8. This is best described as a

(A) respiratory acidosis and metabolic alkalosis

(B) metabolic acidosis with respiratory compensation

(C) mixed acidosis

(D) mixed alkalosis

(E) metabolic alkalosis

3. The diagnosis of malignant hyperthermia is supported by all of the following except

(A) hyperkalemia

(B) CK elevation

(C) acidosis

(D) hypocarbia

(E) temperature elevation

4. Malignant hyperthermia is treated by

(A) external cooling

(B) mannitol

(C) dantrolene

(D) all of the above

(E) none of the above

5. Malignant hyperthermia is best characterized as

(A) a genetic disorder of calcium metabolism

(B) an allergic drug reaction

(C) a disorder of temperature regulation

(D) an increase of the hypothalamic temperature set point

(E) an idiopathic disorder

6. The drug screen is positive for amphetamines. The street drug likely to be responsible for this is

(A) “crack”

(B) OxyContin

(C) ecstasy

(D) cannabis

(E) ketamine

7. Before his deterioration in the recovery room, the child received an anesthetic with isoflurane, nitrous oxide, cisatracurium, and meperidine to have teeth removed. With the drug screen positive for amphetamines, the following must be considered in the differential diagnosis

(A) seizures and a postictal state

(B) neuroleptic malignant syndrome

(C) central serotonin syndrome

(D) all of the above

(E) none of the above

8. The increased synaptic release of serotonin can be as a result of which drug in this case scenario

(A) meperidine

(B) nitrous oxide

(C) methamphetamine

(D) lorazepam

(E) succinylcholine

9. The other agent in this clinical condition that affects serotonin pharmacology is

(A) isoflurane

(B) cisatracurium

(C) phenelzine

(D) lorazepam

(E) fentanyl

10. In the case of neuroleptic malignant syndrome (NMS), the neurotransmitter implicated is

(A) epinephrine

(B) norepinephrine

(C) serotonin

(D) dopamine

(E) GABA

11. The symptoms that are more common in the NMS than in the central serotonin syndrome include all of the following except

(A) hyperthermia

(B) altered mental status

(C) muscle rigidity

(D) myoclonus

(E) none of the above

12. Drugs implicated in the central serotonin syndrome include the following except

(A) dextromethorphan

(B) MAO inhibitors

(C) selective serotonin reuptake inhibitors (SSRIs)

(D) acetaminophen with codeine

(E) lithium

13. The mortality of the central serotonin syndrome (CSS) is

(A) less than 20%

(B) 20-40%

(C) 40-50%

(D) 50-75%

(E) more than 75%

14. Treatment of CSS includes the following except

(A) cyproheptadine

(B) propranolol

(C) mannitol

(D) phenoxybenzamine

(E) none of the above

15. In NMS, treatment includes the following except

(A) bromocriptine

(B) dantrolene

(C) chlorpromazine

(D) mannitol

(E) antipyretics

ANSWERS

1. (A) Hyperthermia is defined as an elevation of core body temperature above 37.5°C. In contrast to fever, which is a cytokine-activated inflammatory response, hyperthermia is a failure of thermoregulation. Obviously, in the child who presents with an elevated temperature, it is frequently not clear whether you are dealing with an inflammatory fever or with a hyperthermic state. Given the absence of a history of inflammatory or clinical features of an infectious disease of any kind, the child described in the case scenario should be presumed to have a hyperthermic state related to one of the medications he received during his medical care or, perhaps, to a medication he ingested himself. In the case described, the appropriate initial interventions as always are the ABCs of urgent care. The patient needs a patent airway, adequate respirations, and hemodynamic stability. After stabilization, a number of laboratory tests may provide helpful information including an ECG. In all the hyperthermic states, it is likely that the patient will have a mixed acidosis. Elevation of muscle enzymes significant enough to cause renal insufficiency, and increased serum concentrations of both potassium and phosphate are also likely present. These aberrations are largely the result of muscle membrane injury, the subsequent release of intracellular contents, and the hemodynamic challenge of significant hyperthermia. Emergency treatment must focus on the distinct possibility of life-threatening dysrhythmias from acidosis and hyperkalemia.

2. (C) When there is an acute change in PCOof 10, the pH will change by 0.08 in the opposite direction. In other words, the pH will fall as the PCOrises. The acidosis or alkalosis present is purely respiratory if all changes are explained by changes in the PCO2. For a change in BE of 10 mEq/L, the pH will change by 0.15 in the same direction. If all changes are explained by a change in the BE, then the process is entirely metabolic.

Assuming a normal blood gas of 7.40, PCO40, PO100, BE 0, in the case presented, the PCOis approximately 35 above the normal PCO2. Divided by 10 and multiplied by 0.08, one would expect the pH to be 0.28 lower than the normal of 7.40, or 7.12. In this case, the pH is 7.07 with a base deficit of −10 and a metabolic acidosis is also present.

3. (D) Given the proximity of this event to a general anesthetic, the first cause of hyperthermia to be considered is malignant hyperthermia (MH). Early clinical findings in MH include masseter muscle spasms, generalized muscle rigidity, sinus tachycardia, increase in COproduction leading to hypercarbia, and elevation in body temperature. Hemodynamic instability, electrolyte abnormalities, and disseminated intravascular coagulation occur later. Appropriately treated, MH has a mortality that is less than 5% (Table 12-1).

4. (D) Appropriate intervention in a patient with suspected or proven MH is immediate cessation of the ongoing anesthetic, aggressive external and internal cooling, and the IV administration of dantrolene. Dantrolene is a drug that interferes with calcium release from the sarcoplasmic reticulum and will put an end to the metabolic abnormality. Because rhabdomyolysis, which may result in acute renal failure, is very common in this disorder, treatment with hydration, bicarbonate to alkalinize the urine followed by diuresis induced by mannitol is also recommended. After a dose(s) of dantrolene is/are given, the treatment of MH is supportive.

5. (A) MH is a rare genetic disorder associated with the administration of a variety of anesthetic agents, particularly the depolarizing muscle relaxant succinylcholine and volatile anesthetic gases. In approximately half of the identified cases, MH is inherited in an autosomal dominant fashion. In the remainder of the cases, inheritance is variable. When exposed to a triggering anesthetic, susceptible patients have the uncontrolled release of calcium from their sarcoplasmic reticulum. This torrential release of calcium results in a marked increase in skeletal muscle metabolism and heat production.

Once the episode has resolved and the patient has recovered, it is suggested that the patient and his first-degree relatives be evaluated for this diagnosis. The diagnosis requires a muscle biopsy, which should be done at a certified MH center. Abnormal augmentation of muscle contraction following treatment of the biopsy specimen with halothane or caffeine is diagnostic. A variety of MH centers are located across the country and can be accessed by calling the Malignant Hyperthermia Hotline (1-800-MH-HYPER/644-9737).

6. (C) In the development of this case scenario, it becomes apparent that this child has a drug screen that is positive for amphetamines. The commonly used street drug responsible for this is ecstasy. Ecstasy is a methamphetamine derivative that significantly impacts the physiology of the human nervous system by alterations in serotonin metabolism.

7. (D) Important causes of severe hyperthermia (>40°C temperature), not related to infectious diseases, are environmental exposure, hypothalamic injury, central serotonin syndrome, MH, and neuroleptic malignant syndrome (Table 12-1). The clinical symptoms associated with these syndromes overlap significantly. Each of these conditions can be associated with multisystem complications, and each can result in death. For CSS to be diagnosed, there needs to be an appropriate history of ingestion of medication that contributes to an increase in serotonin in the CNS. Additionally, the patient must have at least 3 of the following: mental status changes, agitation, myoclonus, muscle rigidity, hyperreflexia, diaphoresis, shivering or tremor, diarrhea, incoordination, and fever.

TABLE 12-1. Contrasting Clinical Features of Syndromes Associated with Severe Hyperthermia

 
 

MALIGNANT HYPERTHERMIA

CENTRAL SEROTONIN SYNDROME

NEUROLEPTIC MALIGNANT SYNDROME

 

Inducing agents

     

amphetamines (include ecstasy)

 

X

 

bromocriptine

 

X

 

chlorpromazine

   

X

clozapine

   

X

cocaine

 

X

 

depolarizing muscle relaxants (eg, succinylcholine)

X

   

dextromethorphan

 

X

 

fluphenazine

   

X

haloperidol

   

X

levodopa or carbidopa (withdrawal)

 

X

X

lithium

 

X

X

lysergic acid diethylamide (LSD)

 

X

 

monoamine oxidase (MAO)

 

X

 

meperidine

 

X

 

metoclopramide

   

X

Phenergan

   

X

risperidone

   

X

selective serotonin reuptake inhibitor (SSRI)

     

and serotonin reuptake inhibitor (SRI)

 

X

 

tricyclic antidepressant (TCA)

 

X

 

tryptophan

 

X

 

volatile anesthetics

X

   

Symptoms

     

diarrhea

 

X

 

dysrhythmia

X

X

X

disseminated intravascular coagulation (DIC)

X

X

X

fever

X

X

X

hypercarbia

X

 

X

hyperreflexia

X

X

X

hypertension

X

X

X

hypertonia/rigidity

X

X

X

hypotension

X

 

X

mental status change

X

X

X

metabolic acidosis

X

 

X

myoclonus

 

X

 

nausea and vomiting

 

X

 

rhabdomyolysis

X

X

X

seizure

 

X

X

tremor

 

X

X

trismus

X

X

 

Treatment

     

amantadine

   

X

antipyretics

X

X

X

bromocriptine

   

X*

chlorpromazine

 

X*

 

cyproheptadine

 

X

 

dantrolene

X

±

X

levodopa or carbidopa

   

X

mannitol

X

X

X

propranolol

 

±

 
 

* These medications may predispose to another syndrome.

8. (C) In general, amphetamines increase release of serotonin at neuronal synapses in the CNS, but they also cause inhibition of serotonin reuptake and breakdown at these synapses. The resultant excess serotonin concentration in the CNS results in a constellation of symptoms that have come to be recognized as CSS.

9. (C) Complicating serotonin physiology in this child is the presence of a MAO inhibitor that the patient takes regularly for depression. MAO inhibitors also prevent the breakdown of serotonin, producing excess CNS serotonin.

10. (D) The neurotransmitter responsible for NMS is dopamine. Blockade of dopamine receptors within the basal ganglia is believed to precipitate symptoms. More than 25 agents have been incriminated in the precipitation of NMS. The most commonly implicated are neuroleptic agents such as haloperidol, the withdrawal of dopamine agonists (eg, Ldopa), other antipsychotic agents such as chlorpromazine and fluphenazine, and the narcotic agonist meperidine.

11. (D) NMS is another drug-induced hyperthermic state that can be confused with CSS. When compared with CSS, patients with NMS are likely to have had gradual onset of symptoms and are less likely to have myoclonus and hyperreflexia. Rigidity found in NMS is more severe than in CSS, but the remainder of the clinical scenario may look much the same.

12. (D) Other agents have been reported to precipitate CSS that include cocaine, L-dopa, lithium, LSD, dextromethorphan, tricyclic antidepressants, serotonin reuptake inhibitors (SRIs), and SSRIs. SRIs are commonly prescribed in pediatric depression making CSS a syndrome that should be well understood by pediatric practitioners. See answer 9.

13. (A) The mortality should be less than 20% assuming the patient arrives at a hospital and receives appropriate intervention.

14. (D) Although producing overlapping syndromes, treatment for these 3 disorders differs. For CSS, symptomatic treatment is appropriate. Dantrolene has been used only in isolated cases. It also may be appropriate to consider the administration of an anti-serotonin medication. Both propranolol and cyproheptadine block serotonin activity at the postsynaptic receptor. It is possible that these drugs may be useful, but their benefit is supported only by case reports.

In both CSS and NMS, it is important to identify the offending agent and eliminate it from the patient’s medication regimen. With respect to MH, the anesthetic will have been discontinued before your involvement in the case and your participation will be to help provide supportive care. Although all of these syndromes pose a threat to life, the mortality of each should be well under 20% when appropriately treated. The key to successful intervention in life-threatening drug-induced hyperthermia is the prompt recognition and elimination of the drug that might have triggered such a response and careful supportive care.

15. (C) Therapy for MH relies heavily on the medication dantrolene, whereas treatment of NMS is largely symptomatic; however, it also can improve with dantrolene and bromocriptine.


SUGGESTED READING

Arnold DH. The central serotonin syndrome: paradigm for psychotherapeutic misadventure. Pediatr Rev. 2002. 23(12):427-432.

Rosenberg MR, Green M. Neuroleptic malignant syndrome. Review of response to therapy. Arch Intern Med. 1989;149: 1927-1931.

CASE 13: A 4-YEAR-OLD GIRL WITH SNORING

A 4-year-old girl is brought in for a routine physical examination. Her family recently moved, and this is their first visit. She has had regular health care and her immunizations are up to date. She snores and her mother allows her to sleep with her so she can “listen to her breathe.” The mother reports she worries because her daughter’s breathing is often irregular with sleep and seems to pause. She is the youngest of 5 siblings, and none of her other children breathes as this child does. Other than 2 episodes of “strep throat,” she has not really been ill.

On physical examination, she appears small for her age. She is less than the 5th percentile for height and weight. Her head circumference is 50th percentile for age. Her entire physical examination, absent the growth parameters, is normal with the exception of moderate tonsillar hypertrophy. Her developmental assessment is normal.

SELECT THE ONE BEST ANSWER

1. It is likely that the following symptom is also prominent

(A) encopresis

(B) poor attention span

(C) echolalia

(D) dysphagia

(E) sleepiness

2. Which is not true about sleep in children?

(A) functional residual capacity falls

(B) upper airway resistance doubles

(C) breathing is not erratic during rapid eye movement (REM) sleep but is erratic during non-REM periods

(D) ventilatory drive is decreased from the awake state

(E) none of the above

3. Spontaneous arousal is a potent defense against sleep-disordered breathing. Which of the following is true about sleep arousals in children?

(A) children have a lower threshold for arousal than adults

(B) moderate hypoxia is the most potent stimulus for arousal in infants during sleep

(C) hypercapnia and increased upper airway resistance are more potent than hypoxemia at stimulating sleep arousals in preschool children

(D) the sleep arousal index in infants is the same as it is in adolescents

(E) all of the above

4. Central apnea in preschool children is significant if it exceeds

(A) 10 seconds

(B) 15 seconds

(C) 20 seconds

(D) 30 seconds

(E) 60 seconds

5. Which is true about central apnea in children?

(A) central apnea is more common than obstructive apnea in children

(B) central apnea is significant only if it is associated with bradycardia

(C) obstructive apnea is more common than central apnea in normal children

(D) apnea associated with transient desaturation is always pathologic in children

(E) obstructive apnea does not occur in children

6. Children with obstructive sleep apnea (OSA) differ from adults in that

(A) children with OSA are more likely to be obese

(B) children with OSA are more likely to have sleep arousal and therefore have more daytime sleepiness than adults

(C) children with OSA are more likely to have REM sleep apnea, whereas adults have apnea with non-REM sleep

(D) children with OSA do not suffer the cardiopulmonary insult that adults do

(E) none of the above

7. Complications of OSA in children include

(A) neurocognitive defects

(B) systemic hypertension

(C) congestive heart failure

(D) failure to thrive

(E) all of the above

8. What is the next diagnostic procedure indicated?

(A) the next step is a strep screen

(B) the next step is polysomnography

(C) the next step is an ultrasound of the neck

(D) the next step is a nasopharyngeal aspirate for viral DFA studies

(E) the next step is a CT scan of the head and neck

9. The treatment of OSA in children usually begins in children with

(A) nighttime oxygen supplementation

(B) nighttime mechanical ventilation

(C) tonsillectomy and adenoidectomy

(D) calorie reduction diet aimed at 15% reduction in body weight

(E) watchful waiting

10. The child with snoring

(A) is always at risk for OSA

(B) rarely has OSA

(C) always requires surgical intervention with tonsillectomy

(D) should always be evaluated by polysomnography

(E) none of the above

11. A tonsillectomy in a patient with OSA is characterized by

(A) increased risk of postoperative respiratory failure as compared with a tonsillectomy in the same age patient with no OSA

(B) immediate improvement of airway symptoms

(C) decreased risk of postoperative bleeding as compared with a tonsillectomy in the same age patient with no OSA

(D) no risk of postoperative respiratory failure as compared with a tonsillectomy in the same age patient with no OSA

(E) all of the above

12. Appropriate anesthetic care of a child with OSA for tonsillectomy should omit

(A) muscle relaxants

(B) volatile agents

(C) nitrous oxide

(D) nonsteroidal anti-inflammatory agents

(E) acetaminophen

13. Appropriate immediate postoperative care from tonsillectomy for the child younger than 2 years of age with significant OSA is

(A) short stay unit observation for 6 hours after surgery

(B) discharge to home from the recovery room after the child demonstrates the ability to drink

(C) admission to the hospital for 24 hours of cardiorespiratory monitoring

(D) A or B

(E) none of the above

14. The risk of postoperative bleeding is highest

(A) on postoperative day 1 or 2

(B) at the end of the first postoperative week

(C) on postoperative day 2 or 3

(D) for the entire first postoperative week

(E) for the first postoperative month

ANSWERS

1. (B) Symptoms of OSA in a child are different than those in an adult. When one compares the child with OSA with the adult, the child frequently also has failure to thrive. In children there are often other concomitant symptoms such as enuresis, behavior abnormalities, and attention deficit disorder.

2. (C) During sleep, functional residual capacity falls, ventilatory drive is decreased from the awake state, and resistance in the upper airway is significantly increased.

3. (C) When compared with adults, children are less likely to have sleep arousal triggered by hypoxia, hypercapnia, or airway resistance. Hypercapnia and airway resistance are more potent stimuli for sleep arousals in children than is hypoxemia. Because sleep arousal is uncommon in children, daytime sleepiness is unusual in children with sleepdisordered breathing.

4. (C) Central apnea is considered significant when it exceeds 20 seconds or is accompanied by bradycardia. Of note, central and obstructive apnea may occur in the same patient.

5. (A) Central apnea is more common than obstructive apnea in children.

6. (C) The child with OSA is rarely an obese patient in contrast to the typical adult OSA patient. A child with OSA frequently also has failure to thrive. In children, REM sleep is the most erratic phase of sleep, and most sleep disorders occur during this phase. This is different from the adult in whom OSA occurs during non-REM sleep. Untreated OSA is a severe health problem and can result in the development of heart failure unresponsive to surgical or medical treatment and ultimately can result in death.

7. (E) Should the symptoms of OSA in children be overlooked, complications will occur. These include neurocognitive difficulties in school, systemic hypertension, and congestive heart failure, including cor pulmonale. The systemic and pulmonary hypertension that accompanies OSA is secondary to the chronic exposure of the pulmonary arterial circulation to hypercarbia and hypoxemia.

8. (B) Children with a significant history of snoring and periods of apnea during sleep should be fully evaluated for OSA with polysomnography. The polysomnogram will evaluate not only central apnea but obstructive apnea as well.

Sleep disorders are very common during childhood, occurring in 20-30% of children. They are generally a source of stress and sleeplessness for parents, and behavioral issues as well as learning difficulties for the child. These difficulties are not necessarily accompanied by OSA. A careful history of breathing disorders with sleep is indicated under these circumstances. Questions about the child’s sleep should be asked, including how long it takes him to fall asleep, the child’s routine bedtime every night, the child’s sleep location, and how much time there is between feeding and bedtime. Should the sleep abnormality be accompanied by significant airway symptoms, polysomnography should be performed to delineate the contribution of airway obstruction to the disorder of sleep. More commonly, disorders of sleep are related to emotional issues and disruption of either home or school and not to OSA.

9. (C) In a child, should the findings on polysomnography be significant, the first treatment option in a child almost without exception is a tonsillectomy and adenoidectomy.

The lymphoid tissue of the upper airway increases in mass until approximately age 12. Simultaneously there is a growth in the size of the upper airway. Between 2 and 8 years of age, the tonsils and adenoids are the largest in relation to the underlying airway, resulting in a relatively narrow upper airway. The prominence of the lymphoid tissue in the upper airway makes a significant contribution to airway obstruction during sleep in children. The prominence of the lymphoid tissue in children may often be responsible for the symptoms of OSA. Most children significantly improve with respect to sleep pathology following tonsillectomy and adenoidectomy.

Should tonsillectomy and adenoidectomy not result in significant improvement in sleepdisordered breathing, further surgical intervention may be necessary. Uvulopalatoplasty is an uncommon surgical intervention in the child with OSA, particularly when compared with the adult patient. In OSA refractory to other interventions, tracheostomy may be required. Nonsurgical treatment for OSA is also a viable therapeutic alternative. However, the use of nighttime constant positive airway pressure (CPAP), common for adults with OSA, is not approved for children (although it is used with some frequency). Further studies in children with OSA for interventions other than tonsillectomy and adenoidectomy are needed.

Most children with OSA are not obese in contrast to most adults. Therefore, a reduced-calorie diet is not indicated.

10. (B) Snoring is a relatively common complaint offered to the pediatrician. Only on rare occasions is snoring a clue to the diagnosis of OSA. In the case presented, the mother describes not only snoring, but also the irregularity of her child’s breathing with sleep, and even occasional periods of apnea. Should sleep abnormality be accompanied by significant airway symptoms as described in this child, polysomnography can determine the contribution of airway obstruction.

11. (A) In general, marked improvement does not occur immediately after the procedure, although there is some resolution in symptoms the first night after surgery. More improvement is seen as the residual anesthetic agent is eliminated and procedure-related edema in the immediate perioperative period resolves.

Children with significant sleep apnea in the perioperative period may well have more apnea during the first 24 hours following tonsillectomy and adenoidectomy.

12. (D) NSAIDs enhance bleeding risk. Thus these medications should not be administered in the perioperative period.

13. (C) Children should be monitored in a setting where respiratory expertise is immediately available. Perioperative desaturation is common in the child with concomitant craniofacial abnormality and in the child younger than 3 years.

14. (B) Bleeding following a tonsillectomy and adenoidectomy occurs commonly at the end of the first postoperative week if not in the first 6 hours after surgery.


SUGGESTED READING

Helfaer MA, McColley SA, Puzik PL, et al. Polysomnography after adenotonsillectomy in mild pediatric obstructive sleep apnea. Crit Care Med. 1996;24(8):1323-1327.

Marcus CL. Sleep-disordered breathing in children. Am J Res Crit Care Med. 2001;164:16-30.

Munford RS, Pugin J. Normal responses to injury prevent systemic inflammation and can be immunosuppressive. Am J Respir Crit Care Med. 2001;163:316-321.

Strollo PJ, Rogers RM. Obstructive sleep apnea. Curr Concepts. 1996;334(2):99-104.

CASE 14: A 16-MONTH-OLD BOY WITH FEVER AND COUGH

A 16-month-old African American boy presents to the emergency department with a 3-day history of fever and cough. He was well until 3 days ago when his mother reports that he began to cough and felt warm to touch. His temperature was 38.5°C. She gave him acetaminophen and put him to bed early. For the last 2 days he has not been hungry but continues to drink well. His fever has persisted despite antipyretics and is now 39°C. There have been no other symptoms, no sick contacts, and no travel history.

On physical examination, the child appears toxic but is well-hydrated. The heart rate is 140, the respiratory rate is 52, and the oxygen saturation is 82% on room air. The only significant finding on examination is markedly decreased breath sounds over the right hemithorax. There is no adenopathy or hepatosplenomegaly.

A chest radiograph reveals an opacified right hemithorax with slight mediastinal shift to the left. The CBC shows a white count of 28,000/mmwith many bands.

SELECT THE ONE BEST ANSWER

1. What is the next diagnostic procedure indicated?

(A) a throat culture

(B) a review of the blood smear

(C) an ultrasound of the right hemithorax

(D) a nasopharyngeal aspirate for viral DFA testing

(E) a repeat leukocyte count

2. Of the following, the most urgently indicated step is

(A) administration of supplemental oxygen

(B) measurement of a blood gas

(C) placement of a thoracostomy tube

(D) bronchoscopy

(E) reviewing the peripheral blood smear

3. Of the following choices, the most appropriate antibiotic regimen for this child is

(A) ampicillin and ceftriaxone

(B) ceftriaxone and vancomycin

(C) amoxicillin and azithromycin

(D) ceftazidime and gentamicin

(E) oxacillin and ceftazidime

4. A large pleural effusion is identified and aspirated from the right hemithorax. Which of the following is indicative of an empyema?

(A) a pH 7.0, glucose 20 mg/dL, total protein 4 g/dL, WBC 20,000/mm3, LDH more than 1000 U/L

(B) a pH 7.2, glucose 80 mg/dL, total protein 4 g/dL, WBC 1000/mm3, LDH 585 U/L

(C) a pH 7.3, glucose 60 mg/dL, total protein 4 g/dL, WBC 500/mm3, LDH 348 U/L

(D) a pH 7.2, glucose 80 mg/dL, total protein 4 g/dL, WBC 5000/mm3, LDH 475 U/L

(E) none of the above

5. If an empyema is identified, the appropriate intervention is

(A) instillation of antibiotics into the pleural space

(B) daily thoracentesis for 7 days

(C) video-assisted thoracoscopy (VAT) and decortication

(D) instillation of chlorhexidine into the pleural space

(E) close observation as an outpatient

6. If, after removal of the effusion, it is apparent that there is a 2-cm lung abscess, the appropriate therapy would be

(A) urgent surgical drainage

(B) elective surgical drainage after antibiotic treatment for 5 days

(C) prolonged parenteral antibiotics

(D) interventional radiology-directed drainage of the abscess

(E) A and C

7. How often is a bacterial pneumonia accompanied by a pleural effusion?

(A) less than 20%

(B) 20-30%

(C) 35-50%

(D) 55-75%

(E) more than 75%

8. Which of the following statements is true?

(A) all patients with a parapneumonic effusion require hospitalization

(B) all pleural effusions require thoracoscopy for resolution

(C) all parapneumonic effusions, if cultured, will be positive for pathogens

(D) all parapneumonic effusions require surgical intervention

(E) small parapneumonic effusions are generally clinically inconsequential and resolve without surgical intervention

9. In this case, the comorbidity that most needs to be considered is

(A) HIV

(B) sickle cell disease

(C) congestive heart failure

(D) hepatitis A

(E) none of the above

10. Which pathogen on this list is the most likely to be implicated in this 16-month-old with a lung abscess?

(A) Chlamydia trachomatis

(B) Moraxella catarrhalis

(C) Staphylococcus aureus

(D) Mycoplasma pneumoniae

(E) Klebsiella pneumoniae

11. In the neonate, the most common pathogens associated with bacterial pneumonia among the choices here are

(A) group B streptococcus and Escherichia coli

(B) H influenzae and Listeria monocytogenes

(C) L monocytogenes and group D streptococcus

(D) group D streptococcus and group B streptococcus

(E) Chlamydia trachomatis

12. In the school-age child, the most likely pathogen in bacterial pneumonia with parapneumonic effusion is

(A) Chlamydia trachomatis

(B) Staphylococcus aureus

(C) Streptococcus pneumoniae

(D) Neisseria meningitidis

(E) H influenzae

13. In the perioperative period after cardiac surgery, a pleural effusion sometimes occurs. Among these patients, chylothorax may occur. A chylothorax would be most characterized by

(A) pH 7.1, protein 4 g/dL, glucose 25 mg/dL, WBC 2,000/mm3, triglycerides: 86 mg/dL

(B) pH 7.3, protein 4 g/dL, glucose 75 mg/dL, WBC 5,000/mm3, triglycerides: 345 mg/dL

(C) pH 7.2, protein 3 g/dL, glucose 85 mg/dL, WBC 200/mm3, triglycerides: 67 mg/dL

(D) pH 7.4, protein 3 g/dL, glucose 210 mg/dL, WBC 30/mm3, triglycerides: 95 mg/dL

(E) none of the above

14. A pleural effusion in the child that suggests malignancy is characterized by

(A) a pH lower than 7.1

(B) a serum glucose less than 40 mg/dL

(C) a blood triglyceride level higher than 500 mg/dL

(D) the presence of atypical white cells

(E) all of the above

15. Malignant pleural effusion is most often seen in the child in

(A) rhabdomyosarcoma

(B) neuroblastoma

(C) hepatoblastoma

(D) lymphoma

(E) medulloblastoma

ANSWERS

1. (C) Although a decubitus film may be obtained, an ultrasound of the right hemithorax and aspiration of the fluid for diagnostic purposes should ideally precede the administration of antibiotics. However, if the child’s clinical condition is rapidly deteriorating, stabilization of the child’s condition and administration of appropriate antibiotics before thoracentesis should proceed without delay.

2. (A) This case represents an example of bacterial pneumonia with an associated pleural effusion. In the emergency department the most appropriate intervention is attention to the airway, adequacy of respiratory effort, and circulation. The child is desaturating on room air and should receive supplemental oxygen. After the patient is stabilized with oxygen and a CXR is acquired, an IV line should be placed and appropriate antibiotics given. Ideally, an ultrasound with aspiration of pleural fluid should be attempted in the stable child before antibiotics.

3. (B) Selection of appropriate antibiotics for this particular patient should include coverage for S aureus and S pneumoniae, as well as consideration of less likely gram-negative pathogens. Community-associated methicillin-resistant S aureus (CA-MRSA) may present with a profound, rapidly progressive, necrotizing pneumonia, so consideration should be given to an IV antibiotic that targets MRSA. Therefore, the best initial choice of antibiotics in this child would be ceftriaxone and vancomycin.

4. (A) The presence of the pleural effusion in this child demands a diagnostic procedure. It is imperative that fluid from this effusion be obtained for diagnostic and therapeutic purposes. The pleural space is a potential space defined in its boundaries by the parietal and visceral pleurae. The parietal pleura cover the inner aspect of the chest wall and the diaphragm; the visceral pleura is strongly adherent to the surface of the lung tissue itself. A thin film of liquid separates these 2 spaces and creates the potential space where fluid may accumulate in a number of pathologic states. In the child with an effusion, diagnostic aspiration and evaluation of pleural fluid are important and will provide information that will inform further therapy.

Pleural fluid can be classified in several ways. Typically, one distinguishes among a transudate, an exudate, and an empyema. An alternative categorization of the fluid findings is a distinction between a simple parapneumonic effusion, a complex parapneumonic effusion, and an empyema. A third schema classifies the parapneumonic effusion into a simple exudative phase, a fibrin proliferative phase, and a stage of organization. The distinction between transudate, exudate, and empyema depends on chemical analysis of the pleural fluid. Pleural fluid that has a fluid-to-serum LDH ratio more than 0.6, a pH 7.3-7.4, and a pleural fluid protein concentration more than 3 g/dL should be considered an exudate. Most transudates have a total protein concentrations less than 3 g/dL and have a pH higher than 7.4. Although a positive pleural fluid culture defines an empyema, the clinician must often decide about empyema when the culture is negative. Because of the efficient clearance of organisms from the pleural space and the natural bacteriostatic host defense mechanisms of the pleural space, the pleural fluid culture may be negative even when there are organisms identified on the gram stain. Prior antimicrobial therapy may also influence the culture results.

5. (C) For the child with a large parapneumonic effusion or an empyema accompanied by mediastinal shift, the management includes drainage of that fluid. Should an empyema be defined by either chemistry or the presence of organisms, VAT and decortication early in the patient’s course is recommended and may abbreviate the hospital stay. Another management strategy for a complicated parapneumonic effusion is the instillation of fibrinolytics into the pleural space if VAT cannot be done.

6. (C) Most children with lung abscess respond to a prolonged course of IV antibiotic therapy; surgical intervention is rarely required. Typically the CXR reveals an air fluid level in the diseased lung field. A CT scan may be necessary to further delineate the size of the abscess and its relationship to the tracheobronchial tree. Rarely the abscess needs to be drained either surgically or by interventional radiology. Drainage may complicate the disease process because there is a risk for crosscontamination of unaffected pulmonary tissue as well as contamination of the pleural space at the time of surgery.

7. (C) Pleural effusion is a common event associated with at least 40% of bacterial pneumonias. Generally, the effusions are uncomplicated and small. The presence of an effusion more than 10 mm in width should be aspirated for diagnostic purposes. If the fluid is compatible with an empyema on microscopic examination and by chemical analysis, drainage is indicated.

8. (E) The case described a child with a complicated parapneumonic effusion and lung abscess. However, in the setting of a simple parapneumonic effusion, the effusion usually resolves with treatment of the underlying pneumonia. If there is a complex parapneumonic effusion that is loculated, causes mediastinal shift, or if an empyema is present, more aggressive drainage of the pleural space is recommended.

9. (B) In general, the clinical manifestations of pneumonia in children include fever, cough, and tachypnea. Although additional signs of respiratory distress such as nasal flaring, accessory muscle use, grunting, and desaturation may be present, a respiratory rate of more than 50 breaths per minute at rest has a relatively high sensitivity of predicting a pneumonic process in an otherwise healthy-appearing infant. Auscultatory findings associated with pneumonia include bronchial breath sounds, rales, rhonchi, wheezes, and diminution in breath sounds.

Acute chest syndrome or pneumonia associated with pleural effusion may be a first-time presentation for an African American child with sickle cell disease. It would be important to take a history for sickle cell disease and validate the child’s hemoglobin type by Sickledex or hemoglobin electrophoresis. Immunodeficiencies both congenital and acquired tend to present earlier than 16 months of age but should be considered as well.

10. (C) In this case, after the removal of the pleural fluid, a 2-cm lung abscess is apparent. The lower respiratory tract infection illustrated by this child occurs most often after initial colonization of the nasopharynx with the offending organism followed by aspiration or inhalation. Disease commonly occurs when a host is colonized with a new bacterium. Of the pathogens listed, the most likely cause is S aureus, although S pneumoniae is the most common cause of bacterial pneumonia. Frequent oral aspiration often occurs in debilitated children, and anaerobic constituents of the upper airway flora should be considered as causes in these patients as well.

Associated bacteremia is present in 10-20% of cases of bacterial pneumonia/empyema. If the child can produce sputum, it may be a useful tool to identify the responsible organism. However, in children younger than about 9 years of age, expectoration of sputum rarely occurs, and pediatricians rely on culture of the pleural fluid and the blood for a “certain” microbiologic diagnosis of pneumonia.

11. (A) The 2 most common organisms causing neonatal infection including bacteremia and pneumonia are group B streptococcus and E coli. Infections caused by other streptococcal species and S aureus have been reported but are less common.

12. (C) The abrupt onset of severe symptoms such as fever, anorexia, and tachypnea should lead the clinician to suspect a bacterial pathogen. The most common cause of bacterial pneumonia remains S pneumoniae. This species is also associated with parapneumonic effusions, which are sometimes complicated. At this age, additional bacterial causes of pneumonia with effusion should also be considered such as S aureus. In the vaccine era, H influenzae has been a rare cause. There are also a variety of less frequent causative organisms. Common causes of pneumonia that are rarely associated with pleural effusion include M pneumoniae and C trachomatis, the latter in young infants. Viral agents, particularly influenza, parainfluenza, RSV, and adenovirus, are also common causes of lower respiratory tract infection. Influenza, parainfluenza, and adenovirus may cause a high fever and all may result in a toxicappearing child, but these viruses rarely produce a pleural effusion.

13. (B) Pleural effusions in children occur for reasons other than complicated bacterial pneumonia. These effusions are associated with chest trauma, cardiac surgery, and congestive heart failure. The hemopneumothorax that occurs after chest trauma is obvious by history and by examination of the aspirated fluid. A transudate is commonly found in the patient with cardiac failure or following cardiac surgery and has the characteristics previously described. A chylothorax may follow trauma or thoracic surgery. It is characterized by a marked elevation in the pleural fluid triglyceride concentration that reflects injury to the lymphatic system. The pH, protein, and glucose are similar to the values found in serum.

14. (D) A pleural effusion in the child with a malignancy can be a transudate or an exudate but contains abnormal or atypical white cells suggestive of a malignancy. Notably, in malignant effusion, the glucose concentration can be as low as encountered in empyema.

15. (D) Malignant pleural effusion is substantially more common in the adult population. When a malignant effusion develops in a child, it is most often associated with a thoracic lymphoma.


SUGGESTED READING

Heffner JE, Brown LK, Barbieri C, et al. Pleural fluid chemical analysis in parapneumonic effusions. Am J Respir Crit Care Med. 1995;151:1700-1708.

Miller MA, Ben-Ami T, Daum RS. Bacterial pneumonia in neonates and older children. In: Taussig LM, Landau LI, eds. Pediatric Respiratory Medicine. St. Louis, MO: Mosby; 1999:644-647.

Pistolesi M, Miniati M, Giuntini C. Pleural liquid and solute exchange. Am Rev Respir Dis. 1989;140:825-847..

Sahn SA. Management of complicated parapneumonic effusions. Am Rev Respir Dis. 1993;148:813-817.

CASE 15: AN 8-MONTH-OLD WITH GENERALIZED SEIZURES

An 8-month-old male infant is brought to the emergency department by his grandmother after he began having jerking movements of his arms and legs that started approximately 20 minutes before presentation to the hospital. The nurse reports that in triage the infant had intermittent jerking of his arms and legs and seemed sleepy. The history is uninformative. His grandmother reports that she has been feeding him only formula over the last 5 days. She has been caring for him while his mother is out of town. Review of symptoms is negative for upper respiratory tract illness, fever, vomiting, diarrhea, or change in eating habits.

On physical examination, the vital signs are normal. He has no obvious jerking movements, but he has diminished muscle tone. His pupils are 3 mm and respond sluggishly to light bilaterally. The anterior fontanel is soft. His cardiorespiratory examination is normal.

SELECT THE ONE BEST ANSWER

1. If the child begins to have generalized seizures in the emergency department, the first intervention must be

(A) administration of phenobarbital

(B) ensure a patent airway

(C) obtain an immediate CT scan of the head, with and without contrast

(D) give 10 mL/kg 50% glucose

(E) none of the above

2. Among the following, the first screening tests that need to be performed are

(A) serum glucose and electrolytes

(B) a CBC and differential

(C) an erythrocyte sedimentation rate and CRP

(D) examination of CSF

(E) CT scan

3. The patient continues to have generalized seizures even after administration of IV lorazepam at a dose of 0.3 mg/kg when the electrolytes are proven normal except for a serum sodium of 118 mEq/L. The intervention required is

(A) IV phenytoin, 5 mg/kg

(B) IV 3% NaCl, 2 mEq/kg

(C) IV phenobarbital, 10 mg/kg

(D) IV normal saline, 2 mEq/kg

(E) IV 10% dextrose, 4 mL/kg

4. Additional history regarding which of the following items would most help to explain why this child had seizures

(A) the manner in which the grandmother is preparing food for the child

(B) the drugs available in the grandmother’s house for accidental ingestion

(C) the family history of seizures

(D) recent use of corticosteroids in the child

(E) none of the above

5. The child’s disposition after the seizures are controlled in the emergency department should be which of the following

(A) the child can now be safely discharged with close follow-up

(B) the child should be referred to an endocrinologist

(C) the child needs to have a genetics workup for adrenal disorders

(D) the child should be admitted to the hospital and have careful monitoring of his serum sodium

(E) B and C

6. If trying to distinguish symptoms of inappropriate antidiuretic hormone (SIADH) from water intoxication, urine electrolytes would be

(A) not useful

(B) likely to show a urine sodium concentration less than 20 mEq/L if water intoxication is to blame

(C) likely to show excessive sodium excretion if SIADH is to blame

(D) likely to show low urine osmolality if SIADH is to blame

(E) likely to show no abnormalities if water intoxication is to blame

7. The optimal time frame to correct the serum sodium to a normal range after the seizures are controlled in the emergency department is

(A) as soon as possible

(B) 6 hours

(C) 24 hours

(D) 72 hours

(E) 4-5 days

8. The complication to be most feared from quickly increasing a patient’s serum sodium is

(A) intracranial hemorrhage

(B) hydrocephalus

(C) pontine demyelination

(D) occipital blindness

(E) stroke

9. Complications from a too rapid correction of serum sodium, most often, are observed in which of the following populations?

(A) young infants

(B) preschool children

(C) school-age girls

(D) young adult women

(E) teenage boys

10. The differential diagnosis of hyponatremia includes all of the following except

(A) diabetes insipidus

(B) SIADH

(C) cerebral salt wasting

(D) congenital adrenal hyperplasia

(E) hypoglycemia

11. The diagnostic studies that would best help narrow the differential diagnosis of hyponatremia would be which of the following?

(A) urine sodium, serum potassium, serum calcium, urine phosphate

(B) urine sodium, serum potassium, serum glucose, serum albumin

(C) serum potassium, serum calcium, serum albumin, bilirubin

(D) urine sodium, serum sodium, serum potassium, serum glucose

(E) none of the above

12. The routine use of hypotonic IV fluids in hospitalized children is

(A) recommended because the infant cannot manage a sodium load

(B) recommended because the sodium requirement in ill children is the same as it is in healthy children

(C) not recommended because the ill infant cannot excrete a sodium load

(D) not recommended because the ill infant cannot routinely excrete excess free water

(E) none of the above

13. The quantity of fluid that can best be called “insensible loss” in a patient with normal vital signs is

(A) 1200 mL/mper day

(B) 500 mL/mper day

(C) 2000 mL/mper day

(D) 1000 mL/mper day

(E) 100 mL/mper day

14. The quantity of IV fluids that can best be called “maintenance” in a child with routine ongoing loss and normal vital signs is

(A) 500 mL/mper day

(B) 1200 mL/mper day

(C) 2500 mL/mper day

(D) 3000 mL/mper day

(E) 4000 mL/mper day

15. Of the following IV fluids listed, which would be the best choice for the child in this case to be on if admitted for observation after seizures stopped in the emergency department?

(A) 5% dextrose, 2000 mL/mper day

(B) 5% dextrose 0.2 normal saline 1200 mL/mper day

(C) 5% dextrose 0.45 normal saline, 1200 mL/m2 per day

(D) 5% dextrose 0.9 normal saline, 1200 mL/mper day

(E) 5% dextrose in lactated Ringer’s solution, 3000 mL/mper day

ANSWERS

1. (B) As a general principle, one must assure that the patient has a stable, patent airway and an appropriate hemodynamic status before proceeding to the next step in management.

2. (A) In a patient with seizures, it is important to obtain serum glucose and electrolytes to initiate the acute evaluation. Generalized seizure activity in an 8-month-old infant is relatively common, and there are a multitude of potential explanations. Metabolic derangements are among the most common causes of seizures in this age group. Although hypomagnesemia may cause seizures, hypoglycemia, hypocalcemia, and hyponatremia are the 3 metabolic disturbances that are most frequently associated with seizures. An examination of CSF is not unreasonable but can wait for consideration in an afebrile and previously healthy child. Consideration should be given to intracranial pathology related either to a congenital malformation or to a traumatic event resulting in intracranial or extracranial hemorrhage. A CT scan is appropriate to consider after the patient is stabilized and the seizure is controlled.

3. (B) Controlling the seizure should begin with the administration of lorazepam intravenously in a dose of 0.1 mg/kg. It is clear that at least part of the reason for this child’s ictal activity is hyponatremia. Thus it is prudent to correct the sodium. In general, if one administers 1 or 2 mEq/kg of sodium to a child with a seizure as a result of hyponatremia, the sodium will rise to a sufficient level that the seizures will be abolished. Hyponatremic seizures can be relatively resistant to anticonvulsant medications including phenytoin and phenobarbital, and IV sodium is often required. Although a cause for the seizure activity has been identified, the evaluation for intracranial pathology should be pursued as well. Hyponatremia might be a result of excess antidiuretic hormone resulting from intracranial malformation or injury.

4. (A) Patients with hyponatremia can be divided into those who present without accompanying dehydration and those who are hypovolemic. A history of fever or trauma should be sought from the caregiver. Additional important information to obtain from the caregivers concerns the manner in which the formula was prepared and the intake and urine output for the proceeding 24 hours. For this child, there is no evidence on examination or by history of any volume loss. Thus he falls into the category of euvolemia with hyponatremia. In this age range the commonest explanation for euvolemic hyponatremia is water intoxication from improper mixing of formula before feeding or exogenous administration of water. The alternative diagnosis in a hyponatremic child who is euvolemic is SIADH. This is generally associated with other pathology, most commonly in the CNS. For the hypovolemic child with a reliable history of volume loss and preexisting normal health, a diagnosis of hyponatremic dehydration is usually associated with acute gastroenteritis.

5. (D) Children with hyponatremic seizures, even from a relatively benign cause such as water intoxication, need to be admitted to hospital and have careful monitoring of the rise of serum sodium. Fortunately, this entity is associated almost uniformly with full recovery.

6. (B) When trying to distinguish water intoxication from SIADH, if the history is unavailable or unreliable, urine studies can be useful. SIADH is a diagnosis that is generally associated with other pathology, most commonly in the CNS. In SIADH, the urine volume is generally decreased because the underlying pathology is the excess absorption of free water at the collecting duct of the kidney. In water intoxication, the urine osmolality is quite low, as is the urine sodium concentration (<20 mEq/L). When hyponatremia is a result of antidiuretic hormone excess, urine osmolality is elevated and the urine sodium is 50-75 mEq/L.

7. (C) Ideally, the serum sodium should be corrected no more than 0.5-1 mEq/L/hour to a normal value with isotonic fluid. The exception is the need to rapidly respond to epileptic activity, at which time a rapid minimal correction of the serum sodium is indicated as noted above. In this child, should the seizures continue after anticonvulsant therapy, it would be appropriate to raise the serum sodium to about 125 mEq/L at which time the seizure activity should stop.

8. (C) Severe neurologic injury resulting from central pontine myelinolysis has been associated with rapid correction of serum sodium in some patients.

9. (D) Central pontine myelinolysis has been most associated with too rapid correction of serum sodium in young women with who receive excess free water in the perioperative period.

10. (A) In addition to SIADH, 2 other pathologic entities deserve mention in a pediatric discussion of hyponatremia: cerebral salt wasting and adrenal insufficiency. In diabetes insipidus, the urine is hypotonic and hypernatremia may develop.

11. (D) The determination of the underlying cause of hyponatremia can be made by evaluating the hydration status of the child in conjunction with electrolyte and urine studies. In cases of hyponatremia with robust urine volume and euvolemic state, water intoxication is almost always the diagnosis. Urine osmolality is quite low, as is the urine sodium (<20 mEq/L). The child is euvolemic with low urine output, a relatively high urine sodium, and high urine osmolality. When hyponatremia is a result of antidiuretic hormone excess, urine osmolality is elevated and the urine sodium is 50-75 mEq/L, which is clearly inappropriate in a child whose serum sodium is quite low. For the hypovolemic child with a reliable history of volume loss and a normal preexisting health status, a diagnosis of hyponatremic dehydration is usually associated with gastroenteritis.

In the case of cerebral salt wasting, the patient is likely hypovolemic, has a robust urine output, and a very high urine concentration of sodium. This occurs almost uniformly in the postoperative care of the patient who underwent a neurosurgical procedure or after severe head trauma.

In the case of adrenal insufficiency, the patient also presents with volume loss. In addition to hyponatremia, the patient is usually hyperkalemic and hypoglycemic and may present in shock. When the etiology of the adrenal insufficiency is congenital adrenal hyperplasia, there are often physical findings consistent with virilization.

12. (D) It is common among hospitalized patients or following surgical procedures to have a self-limited period of excess antidiuretic hormone (ADH) secretion, signaling the kidney to retain free water. With the addition of hypotonic IV fluids in this state, hyponatremia may develop.

Isotonic fluid is often the most appropriate choice for children hospitalized for numerous conditions because the risks of giving isotonic fluid are often less than the risks of giving hypotonic fluid. Hyponatremia is found among 3-5% of hospitalized children. The most common cause is the administration of hypotonic IV fluids. If these children were restricted to water and salt intake that exactly meets their physiologic maintenance, they would be normonatremic. It is sometimes difficult to exactly determine a child’s maintenance needs for water and salt. If a clinician overestimates the volume of fluid needed and a child has increased ADH secretion, that child will retain much of the water given in IV fluids. If the fluids chosen are hypotonic, the serum sodium will be driven down over time.

13. (B) Insensible loss of about 500 mL/mper day occurs in the absence of excess insensible loss, as found in fever or with radiant warmer use.

14. (B) The hospitalized child requires approximately 700-800 mL/mper day of water to excrete a normal solute load. In addition, children require replacement of insensible losses of about 500 mL/mper day. The sum of these requirements leads to a total IV fluid rate of approximately 1200 mL/mper day. Additional IV fluids in excess of 1200-1300 mL/mper day in a child without elevated ADH will generally result in more dilute urine. Excess hydration may be required to replace excess water losses, as occur with dehydration or ongoing losses from diarrhea, fever, or other causes.

Often it is taught that the appropriate IV fluid for children who are younger than 1 year of age is 0.2 N saline and for those older than a year of age, 0.45 N saline at a rate that approximates 2000 mL/mper day. Weight-based formulas found in textbooks of 100 mL/kg/day (4 mL/kg per hour) for the first 10 kg, followed by 50 mL/kg (2 mL/kgper hour) for the next 10 kg, and by 20 mL/kg (1 mL/kg per hour) for each kilogram greater than 20 kg approximate this volume of 2000 mL/m2per day for all weights. These formulas are derived from data published in the 1950s that suggested IV fluids be administered in accordance with metabolic needs of healthy children. However, many hospitalized patients today are not “healthy children” and have increased ADH secretion.

15. (D) Once seizure free, the only intervention necessary in the water-intoxicated child would be to restrict free water. However, if IV fluids are required, an isotonic fluid should be chosen and given at a “maintenance” rate.

The alternative fluid regimen now proposed for the hospitalized child is the administration of isotonic fluids at a maintenance rate that more closely matches the volume required to excrete a solute load and the amount needed to replace insensible losses as discussed in answer 14. However, this provides more than the sodium requirement for any age. The consequences of the administration of excess salt are usually inconsequential for most children without underlying cardiovascular or renal disease but can include pulmonary edema and peripheral edema. Children who require sodium restriction, including those with renal failure, congestive heart failure, and chronic obstructive pulmonary disease such as chronic lung disease following prematurity and cystic fibrosis, are certainly exceptions, and hypotonic fluids are often appropriate.


SUGGESTED READING

Arieff AI. Hyponatremia, convulsions, respiratory arrest, and permanent brain damage after elective surgery in healthy women. N Engl J Med. 1986;314(24):1530-1534.

Ayus JC, Krothapalli RK, Arieff AI. Treatment of symptomatic hyponatremia and its relation to brain damage. N Engl J Med. 1987;317(19):1190-1195.

Keating JP, Schears GJ, Dodge PR. Oral water intoxication in infants. an American epidemic. Am J Dis Child. 1992;145(9): 985-990.

Sterns RH, Riggs JE, Schoechet SS Jr. Osmotic demyelination syndrome following correction of hyponatremia. N Engl J Med. 1986;14(24):1335-1341.