Pediatric Residency Training Program

9

Pulmonology

Lauren J. Witcoff M.D.

  1. Anatomy and Physiology of the Respiratory System
  2. Development
  3. By 16 weeks gestation, the bronchial treehas developed. By 26–28 weeks gestation, sufficient air sacs and pulmonary vasculature have developed so that the fetus is able to survive.
  4. Ninety percent of alveolar developmentoccurs after birth, and alveoli increase in number until 8 years of age.
  5. Anatomy
  6. The right lung contains three lobes, and the left lung contains two lobes, including the lingula.
  7. Infants are at higher risk for respiratory insufficiencythan older children and adults because infants have anatomically smaller air passages, less compliant (stiffer) lungs with a more compliant chest wall, and less efficient pulmonary mechanics.
  8. Congenital malformationsof the respiratory tract may be associated with other congenital anomalies, especially of the cardiovascular system.
  9. Physiology
  10. Pulmonary vascular resistancedecreases after birth when the fetal pulmonary and systemic circulations separate and the lungs ventilate for the first time.
  11. The primary functionof the lungs is gas exchange.
  12. Lung problemsmay be classified as obstructive or restrictive.
  13. Obstructive defectsare secondary to decreased airflow through narrowed airways. Examples include asthma, bronchiolitis, and foreign body aspiration.
  14. Restrictive defectsare secondary to pulmonary processes that decrease lung volume (the amount of air filling the alveoli). Examples include pulmonary edema, scoliosis, pulmonary fibrosis, and respiratory muscle weakness.

P.260

  1. Clinical Assessment of Pulmonary Disease
  2. History

is most important in determining the diagnosis of pulmonary disorders.

  1. The antenatal, prenatal, and neonatal historiesare very important because complications of pregnancy, fetal or postnatal tobacco exposure, prematurity, and airway instrumentation can cause pulmonary problems.
  2. Past medical historyshould include previous respiratory problems, including frequent respiratory tract infections, cough, wheeze, stridor, snoring, and exercise intolerance.
  3. Review of systemsshould include documentation of atopy (asthma), failure to thrive or steatorrhea (cystic fibrosis), choking (aspiration), or recurrent infections (immunodeficiencies).
  4. Family historyshould include assessment for genetic diseases (e.g., cystic fibrosis, asthma).
  5. Environmental historyis extremely important because fumes, strong odors, tobacco smoke, allergens, animals, and day care attendance may cause or exacerbate pulmonary disease.
  6. Physical examination

should emphasize the chest and respiratory system.

  1. In the general assessment, assess for evidence of increased work of breathing, such as tachypnea, nasal flaring, expiratory grunting, and chest wall retractions.
  2. Evaluate ears, nose, and throatfor signs of obstruction, atopy, or infection.
  3. Perform a chest examination.
  4. Inspiratory stridorsuggests extrathoracic obstruction, such as in croup and laryngomalacia (softening and weakness of laryngeal cartilage that collapses into the airway, especially when in the supine position).
  5. Expiratory wheezingsuggests intrathoracic obstruction, as in asthma and bronchiolitis.
  6. Crackles or ralessuggest parenchymal disease, such as in pneumonia and pulmonary edema.
  7. Assess for related findings in other organs, such as heart murmurs, increased second heart sound (elevated pulmonary pressure), eczema, and digital clubbing.
  8. Accessory tests to evaluate pulmonary function
  9. Imaging studiessuch as chest x-ray (CXR), computed tomography (CT) scan, magnetic resonance imaging (MRI), and nuclear studies (e.g., ventilation-perfusion scans).
  10. Arterial blood gas(ABG) is the gold standard to measure oxygenation (PO2) and ventilation (PCO2).
  11. Pulse oximetrynoninvasively measures oxygen saturation (SaO2).
  12. Pulmonary function testing(PFT) helps determine the type and severity of pulmonary dysfunction. PFTs measure airflow as a function of time (spirometry) and lung volumes.

P.261

 

  1. Laryngoscopy and bronchoscopy

are performed in some conditions to visualize the upper or lower airways or to obtain bronchoalveolar lavage specimens for laboratory analysis. Common indications includepersistent pneumonia, cough, stridor, or wheezing.

III. Infectious Disorders of the Respiratory Tract

  1. Epiglottitis
  2. Definition.Epiglottitis is acute inflammation and edema of the epiglottis, arytenoids, and aryepiglottic folds.
  3. Epidemiology.The disorder is most common in children 2–7 years of age, with equal incidence in males and females.
  4. Etiology
  5. Infection.with Haemophilus influenzae type b (HIB) was the most common cause before HIB immunization. Epiglottitis is now rare because of the success of the HIB immunization program.
  6. Group A β-hemolytic streptococcusStreptococcus pneumoniae, and Staphylococcusspecies may also cause epiglottitis.
  7. Clinical features
  8. Abrupt onsetof rapidly progressive upper airway obstruction without prodrome. The following signs and symptoms may occur:
  9. High fever and toxic appearance
  10. Muffled speechand quiet stridor
  11. Dysphagia with drooling
  12. Sitting forward in tripodposition with neck hyperextension
  13. Complete airway obstructionwith respiratory arrest may occur suddenly.
  14. Laboratory studiesdemonstrate leukocytosis with left shift. Ninety percent of patients have a positive blood culture, if the epiglottitis is secondary to HIB.
  15. Epiglottis.appears like a “thumbprint” on a lateral radiograph of the neck.
  16. Differential diagnosis.Croup, bacterial tracheitis, and retropharyngeal abscess are diagnoses to also consider. Table 9-1 compares the clinical features that differentiate supraglottic disorders (e.g., epiglottitis) from subglottic disorders (e.g., viral croup).
  17. Diagnosis.Epiglottitis should be suspected on the basis of clinical features. Visualization of a cherry red swollen epiglottis is made when the airway is established.
  18. Management
  19. Epiglottitis is a medical emergency.
  20. Controlled nasotracheal intubationshould be performed by experienced personnel.

P.262

 

Table 9-1. Differentiating Features of Supraglottic and Subglottic Disorders*

Feature

Supraglottic Disorders

Subglottic Disorders

Stridor

Quiet

Loud

Cough

None

Barky

Voice

Muffled

Hoarse

Dysphagia/drooling

Present

Absent

Fever

High

Low to moderate (croup)
High (tracheitis)

Toxicity

Present

Absent, unless tracheitis is present

Posture

Neck extended, tripod position

Normal

*Supraglottic disorders include epiglottitis and retropharyngeal abscess. Subglottic disorders include bacterial tracheitis and viral croup.

  1. Before intubation, minimize stimulationwhile offering humidified oxygen. Avoid causing distress or examining the throat with a tongue depressor as this may cause respiratory arrest.
  2. Antibiotic therapytypically includes a second- or third-generation intravenous cephalosporin. If epiglottitis is secondary to HIB, rifampin prophylaxis is indicated for unimmunized household contacts younger than 4 years of age.
  3. Laryngotracheobronchitis (Croup)
  4. Definition.Croup is inflammation and edema of the subglottic larynx, trachea, and bronchi.
  5. Epidemiology.There are two forms of croup.
  6. Viral croupis the most common cause of stridor. It typically occurs in children 3 months of age to 3 years of age in the late fall and winter. The male to female ratio is 2:1.
  7. Spasmodic croupoccurs year round in preschool age children.
  8. Etiology
  9. Viral croup
  10. Parainfluenzaviruses are the most common cause.
  11. Other organismsinclude respiratory syncytial virus (RSV), rhinovirus, adenovirus, influenza A and B, and Mycoplasma pneumoniae.
  12. Spasmodic croupis likely secondary to a hypersensitivity reaction.
  13. Clinical features
  14. Viral croup
  15. Begins withupper respiratory infection prodrome for 2–3 days, followed by stridor and cough.
  16. Symptoms include inspiratory stridor, fever, barky cough, and hoarse voice, which typically last 3–7 days. Respiratory distress may occur.
  17. Stridorand cough worsen at night and with agitation.
  18. Wheezingmay occur.
  19. Anterior-posterior radiograph of the neckdemonstrates the “steeple sign” of subglottic narrowing.

P.263

 

  1. Spasmodic croup
  2. Characteristic acute onset of stridor usually occurs at night.
  3. Spasmodic croup typically recurs and resolves without treatment.
  4. Diagnosis.Croup should be suspected on the basis of clinical features.
  5. Management.
  6. Supportive careinvolves using cool mist and fluids. Improvement is also noted when patients are exposed to cool night air.
  7. Children with stridor at restbenefit from systemic corticosteroids, such as intramuscular dexamethasone, nebulized budesonide, or oral corticosteroids, which reduce airway edema.
  8. Children with respiratory distressbenefit from racemic epinephrine aerosols, which vasoconstrict subglottic tissues.
  9. β2-Agonists (e.g., albuterol) are useful when wheezing is appreciated on examination.
  10. Hospitalization.is indicated for children in respiratory distress.
  11. Bacterial tracheitis

is an uncommon, but reemerging, cause of stridor.

  1. Definition.Bacterial tracheitis is acute inflammation of the trachea.
  2. Etiology.Causes include Staphylococcus aureus (60%), Streptococcus, and nontypeable Haemophilus influenzae.
  3. Clinical features
  4. Abrupt onset
  5. Toxicity, high fever, and mucous and pus in the trachea
  6. Management.Appropriate antistaphylococcal antibiotics and airway support are indicated.
  7. Bronchiolitis
  8. Definition.Bronchiolitis is inflammation of the bronchioles. The term is most commonly used to refer to a viral infection that causes inflammatory bronchiolar obstruction.
  9. Epidemiology.
  10. Bronchiolitis is the most common lower respiratory tractinfection in the first 2 years of life.
  11. This disorder predominantly affects children younger than 2 years of age.
  12. The male to female ratio is 2:1.
  13. Epidemics occur from November to April.
  14. Risk of infection is increasedwith day care attendance, multiple siblings, exposure to tobacco smoke, and lack of breastfeeding.
  15. More significant diseaseoccurs in patients with chronic lung disease, congenital heart disease, history of prematurity, immunodeficiency diseases, and in infants younger than 3 months.
  16. Etiology.
  17. RSV.is most common.
  18. Less commoncauses include parainfluenza, adenovirus, rhinovirus, influenza, and Mycoplasma pneumoniae.

P.264

 

  1. Clinical features
  2. Onset is gradual, with upper respiratory symptoms, such as rhinorrhea, nasal congestion, fever, and cough occurring initially.
  3. Progression.of respiratory symptoms takes place.
  4. Tachypnea, fine rales, wheezing, and evidence of respiratory distress
  5. The spleen and livermay appear enlarged as a result of lung hyperinflation.
  6. Hypoxemia.may occur.
  7. Apnea may occur, especially in young infants and in children with a history of apnea of prematurity.
  8. CXR.reveals hyperinflation with air trapping, patchy infiltrates, and atelectasis.
  9. Improvement is noted within 2 weeks. More than 50% have recurrent wheezing.
  10. Complications.may include apnea, respiratory insufficiency, respiratory failure, and death. Bacterial superinfection occurs rarely.
  11. Diagnosis.is made on the basis of clinical features and may be confirmed with viral antigen or antibody testing.
  12. Management.
  13. Treatment is primarily supportivewith nasal bulb suctioning, hydration, and oxygen as needed.
  14. Careful handwashingto prevent spread of infection is necessary.
  15. Nebulized bronchodilatorsare controversial and may only be effective in up to 50% of patients.
  16. Steroids.are controversial and may be most effective in patients with a prior history of wheezing.
  17. Nebulized racemic epinephrinemay be effective in reducing airway constriction.
  18. Aerosolized ribavirin, a nucleoside analog with in vitro activity against RSV, may be considered for very ill infants. Evidence of definitive benefit is lacking.
  19. Hospitalization.is indicated for respiratory distress, hypoxemia, apnea, dehydration, or underlying cardiopulmonary disease.
  20. RSV monoclonal antibody(palivizumab [Synagis]) may be given prophylactically by monthly intramuscular injection during RSV season to prevent severe disease in infants with a history of prematurity, chronic lung disease, or cyanotic or hemodynamically significant congenital heart disease.
  21. Pneumonia
  22. Definition.Pneumonia involves infection and inflammation of lung parenchyma.
  23. Epidemiology.Pneumonia is associated with poverty, multiple siblings, exposure to tobacco smoke, and prematurity, as well as urban residence.
  24. Etiology.Causes may be classified based on the child's age (Table 9-2).

P.265

 

Table 9-2. Age and Its Relationship to Pneumonia Etiology

Age

Typical Causes

0–3 months

Congenital infections, such as syphilis, toxoplasmosis, CMV, rubella, herpes simplex virus, and tuberculosis
Intrapartum acquired infections, such as group B streptococcus (most common infection), Gram-negative rods, and Listeria monocytogenes
Postpartum infections, such as RSV and other respiratory viruses
Afebrile pneumonitis caused by Chlamydia trachomatis, Ureaplasma urealyticum, Mycoplasma hominis, CMV, and PCP

3 months–5 years

Viruses, such as adenovirus, influenza A and B, parainfluenza, and RSV (note that RSV pneumonia is generally uncommon beyond 2–3 years of age)
Bacteria, most commonly Streptococcus pneumoniae, but may also include Staphylococcus aureus and HIB

Age 6 and older

Mycoplasma pneumoniae and Chlamydia pneumoniae increasingly common
Viruses, such as adenovirus, influenza A and B, and parainfluenza
Bacteria, most commonly S. pneumoniae

CMV= cytomegalovirus;RSV= respiratory syncytial virus;HIB=Haemophilus influenzae type b;PCP= Pneumocystis carinii pneumonia.

  1. Viruses are the most common cause of pneumonia in all age groups.
  2. Recurrent or persistent pulmonary infiltratesmay have many causes (Table 9-3).
  3. Clinical features, diagnosis, and managementvary depending on etiologic agent.
  4. Viral pneumonia
  5. Symptomsoften begin with upper respiratory complaints, such as nasal congestion and rhinorrhea. Fever, cough, and dyspnea typically follow.
  6. Physical examinationmay demonstrate tachypnea, wheezing, rales, or respiratory distress.
  7. Diagnosisis suggested by interstitial infiltrates on CXR and a white blood cell (WBC) count20, 000 cells/mm3 with a lymphocyte predominance.
  8. Managementis supportive.
  9. Bacterial pneumonia
  10. Symptomshave more rapid onset and greater severity. Fever, cough, and dyspnea typically occur without preceding upper respiratory symptoms.
  11. Physical examinationmay demonstrate rales, tachypnea, decreased breath sounds, and evidence of respiratory distress.
  12. Diagnosisis suggested by a WBC count20, 000 cells/mm3 with a neutrophil predominance, and lobar consolidation on CXR.
  13. Managementincludes appropriate antibiotics and supportive care.
  14. Chlamydia trachomatisis a common cause of afebrile pneumonia at 1–3 months of age.

P.266

 

Table 9-3. Causes of Recurrent or Persistent Pulmonary Infiltrates

Single Lobe

Multiple Lobes

Intraluminal obstruction
   Foreign body
   Tumor
   Mucus plug

Aspiration
   Impaired gag or swallow
   Esophageal obstruction or dysmotility   GERD

Extraluminal obstruction
   Enlarged lymph node from infection
   or malignancy

Mucociliary clearance dysfunction
  Cystic fibrosis
  Ciliary dyskinesia (e.g., immotile cilia
syndrome)

Structural abnormalities
Bronchial stenosis
Bronchiectasis
Right middle lobe syndrome
Congenital lung abnormalities, such
as cysts or sequestration

Bronchopulmonary dysplasia (chronic lung disease)

 

Miscellaneous
 Congenital heart disease
  α1-Antitrypsin deficiency
  Sickle cell disease
  Hypersensitivity pneumonitis
  Pulmonary hemosiderosis

 

Asthma

 

Immunodeficiency diseases

GERD = gastroesophageal reflux disease.

  1. Symptomsinclude a staccato-type cough, dyspnea, and absence of fever. A history of conjunctivitis after birth may be identified in 50% of patients.
  2. Physical examinationmay demonstrate tachypnea and wheezing.
  3. Diagnosisis suggested by eosinophilia and CXR with interstitial infiltrates. Definitive diagnosis is by positive culture or direct fluorescent antibody (DFA) staining of cells from conjunctiva or nasopharynx.
  4. Managementincludes oral erythromycin or azithromycin.
  5. Mycoplasma pneumoniaeis one of the most common causes of pneumonia in older children and adolescents.
  6. Symptomsinclude low-grade fever, chills, nonproductive cough, headache, pharyngitis, and malaise. The cough may last 3–4 weeks.
  7. Lung examinationmay demonstrate widespread rales. Examination findings are often worse than expected by history.
  8. Diagnosis
  9. Positive cold agglutininsare suggestive but not specific.
  10. CXRfindings vary but may show bilateral diffuse infiltrates.
  11. Definitive diagnosisis by elevation of serum IgM titers for Mycoplasma.
  12. Managementincludes oral erythromycin or azithromycin.
  13. Pertussis

Pertussis is an acute respiratory infection also known as “whooping cough.”

  1. Etiology.Bordetella pertussis is the major pathogen responsible for infection. B. parapertussis causes illness that appears clinically very similar to pertussis.

P.267

 

  1. Epidemiology.
  2. Routine immunization beginning at 2 months of age has been effective in reducing the overall incidence of pertussis infection (see Chapter 1, section III.C.2).
  3. Infants younger than 6 months of ageare most at risk for severe disease.
  4. Adolescents and adultswhose immunity has waned are the major source for pertussis infection of unimmunized or underimmunized children.
  5. Infection is highly contagious.
  6. Clinical features
  7. Incubation period is typically 7–10 days.
  8. Pertussis is characterized by 3 stages.
  9. Catarrhal stage(lasts 1–2 weeks) is characterized by upper respiratory symptoms such as rhinorrhea, nasal congestion, conjunctival redness, and low-grade fever.
  10. Paroxysmal stage(lasts 2–4 weeks) is characterized by fits of forceful coughing (“paroxysms”) that are the hallmark of pertussis. A whoop is an inspiratory gasp heard at the very end of a coughing fit (the whoop is heard rarely in young infants). The coughing fits are exhausting, and post-tussive vomiting is common. Young infants may havecyanosis, apnea, and choking during the paroxysms of cough. Between the fits, children appear well and are afebrile.
  11. Convalescent phase(lasts weeks to months) is a recovery stage in which paroxysmal cough continues but becomes less frequent and less severe over time.
  12. Diagnosis.
  13. Diagnosis is suspected based on clinical features.
  14. White blood cell count is elevated with a lymphocytosis.
  15. Diagnosis is confirmed by identification of the organism on culture(gold standard) of nasopharyngeal secretions plated on Regan-Lowe or Bordet-Gengou media, or by positivedirect fluorescent antibody tests of nasopharyngeal secretions.
  16. Management.
  17. Hospitalization.of young infants often occurs during the paroxysmal phase because of choking, apnea, or cyanosis. Supportive care and oxygen (if needed) are important therapies.
  18. Antibiotics.are given to all patients to prevent the spread of infection (azithromycin or erythromycin is used). Antibiotics do not alter the patient's clinical course unless they are administered during the catarrhal phase or very early in the paroxysmal phase.
  19. Respiratory isolationis needed until antibiotics have been given for at least 5 days.

P.268

 

  1. Noninfectious Disorders of the Respiratory Tract
  2. Asthma (Reactive Airway Disease)
  3. Definition
  4. Asthma is a chronic inflammatorydisorder of the airways that causes recurrent episodes of wheezing, cough, dyspnea, and chest tightness.
  5. Symptomsare typically associated with widespread, variable airflow obstruction that is at least partially reversible, either spontaneously or with therapy.
  6. Inflammationcauses airway hyperresponsiveness to many stimuli.
  7. Epidemiology.Asthma is the most common chronic pediatric disease.
  8. Fifty percentof children have symptoms by 1 year of age and ninety percent by 5 years of age.
  9. Thirty to fifty percenthave remission by puberty.
  10. Etiology
  11. Predisposing factorsinclude atopy, family history of asthma, and exposure to tobacco smoke. Infection, diet, and pollution increase susceptibility in predisposed patients.
  12. Trigger factorsof exacerbations include respiratory infections, exercise, cold air, emotions, allergens, gastroesophageal reflux, and exposure to pollutants.
  13. Asthma may accompany other acute or chronic lung diseases, such as cystic fibrosis.
  14. Pathophysiology.Mechanisms include smooth muscle bronchoconstriction, airway mucosal edema, increased secretions with mucous plugging, eventual airway wall remodeling, and production of inflammatory mediators (e.g., IgE).
  15. Clinical features
  16. Typical features during an exacerbationinclude tachypnea, dyspnea, nasal flaring, retractions, and multiphonic wheezing with a prolonged expiratory phase.
  17. Some patients have only chronic or recurrent cough.
  18. CXRoften reveals hyperinflation, peribronchial thickening, and patchy atelectasis.
  19. PFTsreveal increased lung volumes and decreased expiratory flow rates.
  20. Diagnosis
  21. The basis of diagnosis isclinical features and, usually, a therapeutic response to a bronchodilator trial.
  22. “All that wheezes is not asthma.”
  23. Differential diagnosis of acute wheezing (Figure 9-1)
  24. Differential diagnosis of recurrent or chronic wheezing (Figure 9-2)
  25. Management.Treatment depends on the severity of illness and trigger factors. Self-management with a normal lifestyle is the primary goal.
 

Figure 9-1. Differential diagnosis of acute wheezing.

  1. P.269
  2. Preventionof initial disease development and of secondary exacerbations is critical to effective management.
  3. Effectivecontrol of asthma
  4. Assessment and monitoringof asthma symptoms involve home assessments of peak expiratory flow rates (peak flows) and a symptom diary. Parents and patients should be instructed concerning using peak flow measurements to guide changes in medication or to know when to seek acute medical care.
  5. Control of trigger factorsincludes avoidance of causal allergens, dust mites, molds, animal dander, cockroaches, pollens, smoke, pollution, and irritants.
  6. Patient and family education
  7. Pharmacologic therapyis added in a stepwise fashion based on disease severity (Table 9-4).
  8. Sympathomimetics
  9. β2-Adrenergic agonistsmay be given by inhaler or by nebulization.
  10. Short-acting bronchodilators(e.g., albuterol) are first-line therapies for exacerbations. They can also be used for prevention of exercise-induced symptoms.

iii.        Long-acting preparations may be used for chronic control.

  1. If the asthma is persistent (i.e., more severe than intermittent), it is more effectively controlled by the addition of anti-inflammatory medications.
  2. Cromolyn sodium and nedocromil sodium
  3. Anti-inflammatoryprophylaxis is induced by inhibition of activation and release of inflammatory mediators.

P.270

 

 

Figure 9-2. Differential diagnosis of recurrent or chronic wheezing. BPD/CLD = bronchopulmonary dysplasia/chronic lung disease.

  1. These drugs have no effect on acute symptomsbut may help prevent exacerbations.
  2. Corticosteroids
  3. These drugs are the most effective anti-inflammatoryagents.
  4. Systemic steroidsare given for 5–10 days for moderate to severe exacerbations.

P.271

 

Table 9-4. Categories of Asthma Severity and Their Management

Category

Clinical Characteristics

Management

Intermittent

Daytime symptoms ≤2×/week
Nighttime symptoms ≤ 2×/month

No daily medication
Short-acting inhaled β2-agonist for symptom relief
Anti-inflammatory agents not needed

Mild persistent

Daytime symptoms > 2×/week, but < 1×/day
Nighttime symptoms > 2×/month
FEV1≥ 80% predicted (normal)

Short-acting inhaled β2-agonist for symptom relief
Low-dose inhaled corticosteroid (preferred) or cromolyn sodium or leukotriene modifier

Moderate persistent

Daiy symptoms
Nighttime symptoms >1×/week
FEV1 60-80% predicted
Daily use of inhaled short-acting β2-agonist

Short-acting inhaled β2-agonist for symptom relief
Medium-dose inhaled corticosteroid
OR
Low-dose inhaled corticosteroid and long-acting inhaled β2-agonist

Severe persistent

Continuous symptoms
Frequent nighttime symptoms
Limited physical activity
FEV1 ≤ 60% predicted

Short-acting inhaled β2-agonist for symptom relief
High-dose inhaled cortico- steroid and long-acting β2-agonist
Long-term systemic cortico- steroids, if needed

FEV1 = forced expiratory velocity in 1 second.
Adapted from the National Heart, Lung, and Blood Institute, National Asthma Education and Prevention Program Expert Panel Report: Guidelines for the Diagnosis and Management of Asthma—Update On Selected Topics 2002.

iii.        Inhaled steroids are very effective in preventing exacerbations.

  1. Anticholinergic agents(e.g., atropine or ipratropium bromide [Atrovent])
  2. These agents are used as second-line bronchodilators.
  3. These agents decrease airway vagal toneand block reflex bronchoconstriction, and they may be useful in severe exacerbations.
  4. Leukotriene modifiers(montelukast, zafirlukast) are oral anti-inflammatory agents for long-term control of mild, persistent asthma.
  5. Methylxanthines (theophylline)play a controversial role in asthma management. They are bronchodilators with possible anti-inflammatory effects but have a narrow toxic–therapeutic ratio, and their use has therefore decreased.
  6. Cystic Fibrosis (CF)
  7. Definition.CF is a multisystem disorder that results in altered content of exocrine gland secretions.

P.272

 

  1. Epidemiology
  2. CF affects 1 in 2, 500 Caucasians, with equal incidence in males and females.
  3. Five percent of Caucasians are carriers.
  4. Median age of survivalis 31 years.
  5. Etiology.CF is an autosomal recessive disease resulting from a genetic mutation on chromosome 7.
  6. Pathophysiology
  7. The genetic defectproduces an abnormal ion-channel regulator (CFTR) protein that causes sodium and chloride transport dysfunction in epithelial cells.
  8. Abnormal mucusproduced in airways helps create airway obstruction, inflammation, and infection.
  9. Clinical features. Classic hallmarks of CFinclude chronic progressive pulmonary insufficiency, pancreatic insufficiency, and high sweat electrolytes. Clinical expression is variable. See Table 9-5 for the multisystem signs and symptoms of CF.
  10. Meconium ileus at birthis present in 20% of patients.
  11. Recurrentor chronic respiratory symptoms, steatorrhea, and failure to thrive (FTT) are typical presenting features.
  12. Respiratory signs and symptomsinclude chronic productive cough, dyspnea, lung hyperinflation, lung crackles, wheezing, digital clubbing, and progressive hypoxemia.
  13. PFTsshow decreased respiratory flow rates (consistent with obstruction) and eventually decreased lung volumes (consistent with restriction).
  14. Pneumoniadevelops as lungs become colonized, first with Staphylococcus aureus, and later with Pseudomonas aeruginosa.

Table 9-5. Clinical Features of Cystic Fibrosis (CF)

Organ System

Specific Feature

Chronic sinopulmonary disease

Persistent colonization or infection with CF pathogens, such as Staphylococcus aureus, Pseudomonas aeruginosa, or Burkholderia cepacia
Chronic cough, wheeze, sputum production
Mucus plugging
Nasal polyps and chronic sinusitis
Chest radiograph abnormalities including bronchiectasis, atelectasis, pulmonary infiltrates, and hyperinflation

Gastrointestinal abnormalities

Meconium ileus and distal intestinal obstruction syndrome
Rectal prolapse
Pancreatic insufficiency and recurrent pancreatitis
Chronic hepatic disease

Nutritional abnormalities

Failure to thrive, hypoproteinemia, and edema
Fat-soluble vitamin deficiencies (A, D, E, K)

Metabolic abnormalities

Salt depletion, classic electrolytes: hyponatremic, hypochloremic, hypokalemic metabolic alkalosis

Other

Digital clubbing and obstructive azoospermia

  1. P.273
  2. Common pulmonary complicationsinclude hemoptysis, pneumothorax, asthma, chronic sinusitis, and nasal polyps. Recurrent pneumonia, bronchiectasis, pulmonary fibrosis, cor pulmonale, and respiratory failure eventually occur.
  3. Pancreatic insufficiencyoccurs in 90% of patients, with malabsorption predisposing to malnutrition and FTT.
  4. Diagnosisrequires:
  5. One or morephenotypic features or positive family history or increased immunoreactive trypsinogen on newborn screen.
  6. Laboratory evidenceof abnormal CFTR, including sweat chloride > 60 mmol/L or two CF mutations or a characteristic ion transport abnormality across the nasal epithelium.
  7. Management.Treatment requires a team approach and includes:
  8. Antibioticsfor pulmonary exacerbations
  9. Pulmonary toiletwith chest percussion and antimucous therapy
  10. Bronchodilatorsfor wheezing
  11. Good nutrition, pancreatic enzyme replacement, and fat-soluble vitamins(vitamins A, D, E, and K)
  12. Oxygenas needed for hypoxemia
  13. Anti-inflammatoryand immunosuppressive therapy
  14. Lung transplantationand, ultimately, future gene therapy
  15. Psychological supportfor patients and families
  16. Chronic Lung Disease (CLD; also termed bronchopulmonary dysplasia [BPD]; see also Chapter 4, section VI.G.2.a)
  17. Definition.CLD is oxygen dependency beyond 28 days of life.
  18. Epidemiology.CLD most commonly occurs in children born prematurely who suffered from respiratory distress syndrome (hyaline membrane disease or surfactant deficiency syndrome).
  19. Etiology and pathophysiology. CLD follows acute lung injuryand results in a continuum of altered lung repair and function.
  20. Causes of acute lung injurymay include barotrauma from mechanical ventilation, meconium aspiration syndrome, or infection.
  21. Secondary lung injurycaused by oxidants and proteases typically follows the acute injury.
  22. Healing of lung tissue is typically abnormaland is characterized by altered airway and parenchymal remodeling with resultant lung tissue fibrosis, chronic airflow limitations, and diminished lung compliance. This results in both obstructive and restrictive lung disease.
  23. Clinical featuresvary and range from transient oxygen dependency to prolonged need for ventilatory support.
  24. Diminished oxygenation(PaO2) and hypercarbia (PaCO2) are often found on ABG testing.
  25. Intermittentepisodes of tachypnea, wheezing, sputum production, and respiratory distress typically occur.
  26. Frequent respiratory tract infections, airway hyperreactivity, and pulmonary hypertension may result.

P.274

 

  1. CXRtypically demonstrates hyperinflation, atelectasis, and linear or cystic radiodensities.
  2. Nonpulmonary manifestationsmay include increased caloric needs and delayed growth and development.
  3. Management.
  4. Administer supplemental oxygenor ventilatory support as needed.
  5. Optimize pulmonary functionwith bronchodilators, diuretics, anti-inflammatory agents, and fluid restriction.
  6. Optimize caloric intakeand growth.
  7. Prevent complicating infectionsthrough appropriate immunization practices and early antibiotic treatment.
  8. Focus on early identification of complications, such as subglottic stenosis, gastroesophageal reflux disease, and tracheobronchomalacia.
  9. Prognosis.Pulmonary symptoms and disease often diminish with time and growth. Some patients have increased risk of sudden death, continued airway hyperreactivity, hyperinflation, and increased risk of respiratory infections.
  10. Foreign Body Aspiration
  11. Epidemiology.Children 3 months–5 years of age are at greatest risk for small object aspiration.
  12. Etiology. Typical aspirated objectsinclude seeds, popcorn, hot dogs, candy, grapes, and small toy parts.
  13. Clinical features depend on location and biologic reactivityof material aspirated.
  14. Historymay elicit choking episode in 50–80% of cases.
  15. Laryngotracheal foreign bodies(extrathoracic) result in cough, hoarseness, and inspiratory stridor.
  16. Bronchial foreign bodies(intrathoracic; right bronchus slightly more common than left)
  17. Asymmetric findings on auscultation
  18. Completeobstruction with atelectasis, partial ball-valve obstruction with unilateral emphysema, or no obstruction that initially can be asymptomatic
  19. Localized wheezing, persistent pneumonia, chronic cough, or hemoptysis
  20. Esophageal foreign bodies may compress the trachea, producing respiratory symptoms.
  21. Diagnosis.is challenging. Have a high index of suspicion!
  22. A radiopaqueobject is evident on CXR in only 15% of cases.
  23. Consider inspiratory and expiratory films, bilateral decubitus filmsin young children who cannot inspire and expire on command, or fluoroscopy to identify air trapping distal to a foreign body.
  24. Management.
  25. Basic life supportis the initial management for a severe choking episode.

P.275

 

  1. Natural cough, if present, is the most effective expulsive mechanism.
  2. Foreign bodiesthat remain in the airway must be removed by bronchoscopy.
  3. Apnea, apparent life-threatening event (ALTE), and sudden infant death syndrome (SIDS)
  4. Definitions
  5. Apnea of infancyis the unexplained cessation of breathing for $ 20 seconds, or a shorter respiratory pause associated with bradycardia, cyanosis, pallor, or hypotonia in a full-term infant.
  6. Respiratory pausemay be central (no respiratory effort), obstructive (efforts at respiration are made, but are unsuccessful usually because of upper airway obstruction), or both.
  7. Short central apneafor ≤ 15 seconds is normal at all ages.
  8. Apnea of prematurityis the unexplained cessation of breathing for $ 20 seconds in a premature infant (see also Chapter 4, section IX).
  9. Periodic breathingis a breathing pattern with three or more respiratory pauses lasting at least 3 seconds each, with less than 20 seconds of normal respiration in between.
  10. ALTEis a frightening event characterized by some combination of apnea, color change, change in muscle tone, choking, or gagging, in which recovery occurs only after stimulation or resuscitation.
  11. SIDSis the sudden death of a child younger than 1 year of age that is unexplained after a thorough investigation, including a complete autopsy, an examination of the death scene, and a review of the clinical history.
  12. Epidemiology
  13. SIDS reaches its peak incidence at 2–4 monthsof age, and 95% of cases occur before 6 months of age.
  14. Risk factors for SIDS
  15. Prone sleeping position
  16. Soft bedding, overbundling, and overheating
  17. Prematurity
  18. Being the twinof a sibling who died of SIDS
  19. Low birth weightor growth retardation
  20. Recent illness
  21. Lack of breastfeeding
  22. Maternal smoking, drug abuse, or infection
  23. Etiology
  24. Apnea of prematurityis usually caused by immature central respiratory center control.
  25. Obstructive apneamay be secondary to craniofacial anomalies, adenotonsillar hypertrophy, obesity, or hypotonia.
  26. The cause of SIDS is unknown.
  27. No definite cause and effect relationshiphas been proven among apnea, ALTE, and SIDS.

P.276

 

  1. Differential diagnosis of ALTE
  2. Seizure disorder
  3. Gastroesophageal reflux disease (GERD)
  4. Upper airway obstruction
  5. Intracranial mass lesion
  6. Sepsis or other infections, including RSV, pertussis, and meningitis
  7. Metabolic abnormalities, including electrolyte imbalanceand hypoglycemia
  8. Inborn errors of metabolism
  9. Arrhythmia, including long QT syndrome
  10. Abnormal central controlof breathing
  11. Munchausen by proxy
  12. Nonaccidental trauma(shaken baby syndrome)
  13. Evaluation
  14. Detailed history and physical examinationis necessary.
  15. Further testingis based on clinical impression from the history and physical and may include:
  16. Hospital observationand monitoring
  17. Blood work, including complete blood count, ABG, electrolytes, and evaluation for infection
  18. CXR, electrocardiogram, and electroencephalogram
  19. Multichannel recording (sleep study), which simultaneously evaluates oxygen saturation, airflow, chest wall movement, and cardiac rhythm
  20. Barium esophagram or pH probe studyto evaluate for GERD.
  21. Imagingstudies of the head and neck
  22. Workupfor metabolic disease
  23. Management
  24. Teach caregivers cardiopulmonary resuscitation techniques.
  25. The efficacy of home monitoringin reducing infant morbidity and mortality is not well established. Recommended indications for home cardiorespiratory monitoring include:
  26. History of ALTE
  27. Documentationof clinically significant apnea on sleep study
  28. Apnea of prematurity
  29. Documented central hypoventilation
  30. Consider monitorsfor siblings of SIDS victims, infants of substance-abusing mothers, and oxygen-dependent infants.
  31. Prevention of SIDS
  32. Sleep on back
  33. Firm bedding
  34. Avoid overheating
  35. Smoke-free environment
  36. Early prenatal care and regular well child care
  37. Breastfeed

P.277

 

Review Test

  1. A 2-year-old toddler presents with a 3-day history of increasing inspiratory stridor, cough, and increased work of breathing. On examination, you confirm the inspiratory stridor and also note intercostal retractions and tachypnea with a respiratory rate of 44 breaths/min. Which of the following is correct regarding the cause and management of the probable diagnosis?

(A) Parainfluenza virus is the most likely cause.

(B) Foreign body aspiration is unlikely because of the absence of a history of choking.

(C) Albuterol nebulization should be administered.

(D) A “thumbprint sign” will be found on a lateral radiograph of the neck.

(E) Antibiotics against Staphylococcus aureus are indicated.

  1. A 5-month-old female infant in a day care facility develops a low-grade fever to 100.8°F (38.2°C), rhinorrhea, and cough. A few days later, she is brought to the emergency department with tachypnea, chest retractions, diffuse expiratory wheezing, and fine inspiratory crackles bilaterally. Which of the following is correct regarding her likely diagnosis?

(A) Chest radiography will demonstrate decreased lung volumes with bilateral lobar consolidation.

(B) Chlamydia trachomatis should be considered as a possible etiologic agent.

(C) Supportive care is the most important management.

(D) Intravenous erythromycin should be started.

(E) Ribavirin should be administered.

  1. A previously healthy 13-year-old boy presents with a 2-week history of nonproductive cough and low-grade fever. On examination, you note a normal respiratory rate and no evidence of respiratory distress, but are surprised to also hear inspiratory rales at the bilateral lung bases. Which of the following is the most likely cause of pneumonia in this adolescent?

(A) Pneumocystis carinii

(B) Staphylococcus aureus

(C) Group B streptococcus

(D) Haemophilus influenzae type b

(E) Chlamydia pneumoniae

  1. A 7-month-old male infant presents with failure to thrive, and he has had two previous episodes of pneumonia. Past medical history is also significant for meconium ileus during the neonatal period. Which of the following is correct regarding his likely diagnosis?

(A) Electrolytes demonstrate hypernatremic, hyperchloremic metabolic alkalosis.

(B) His lungs are likely colonized with Staphylococcus aureus.

(C) Pulmonary function studies show increased lung volume consistent with restrictive lung disease.

(D) There is a 50% chance that a subsequent sibling will have the same illness.

(E) Pathophysiology involves abnormal calcium transport.

  1. A 5-year-old girl presents with failure to thrive. Workup reveals a sweat chloride level of 90 mmol/L, which is consistent with cystic fibrosis. Which of the following is true regarding this patient's management?

(A) True malabsorption is uncommon and if it occurs, the malabsorption responds well to good nutrition.

(B) Antibiotic therapy should be avoided to prevent development of resistant organisms.

(C) Bronchodilators are ineffective in this condition.

(D) Replacement of vitamin K is necessary.

(E) Chest physical therapy provides little added benefit.

P.278

 

  1. A male infant born at 29 weeks gestation was diagnosed with surfactant deficiency syndrome. He required 3 months of mechanical ventilatory support and oxygen therapy. Now he is ready for discharge from the neonatal intensive care unit and will go home on 0.25 L/min of oxygen. Which of the following is likely to be correct regarding his lung function?

(A) He will probably develop obstructive lung disease.

(B) Because of the difficulties breathing and swallowing in young premature infants, his caloric intake should be minimized.

(C) His lung function will continue to deteriorate with time and further growth.

(D) His chest radiograph will be normal because he has clinically improved.

(E) His lung disease should not affect his development.

  1. A 3-month-old female infant required mouth-to-mouth resuscitation by her mother when she became blue and limp after feeding. In the emergency department, the physical examination is completely normal. Which of the following is correct regarding her presentation?

(A) A home apnea monitor should be ordered and will prevent sudden infant death syndrome in this high-risk infant.

(B) Her presentation likely represents periodic breathing, and reassurance should be given.

(C) Sweat chloride test should be performed to rule out cystic fibrosis.

(D) Even though no seizure activity was witnessed, an electroencephalogram should be considered as part of the evaluation.

(E) Given a normal examination in the emergency department, the patient may be discharged home with close follow-up.

  1. A 3-year-old boy presents with acute onset of fever to 103.5°F (39.7°C), diminished appetite, and drooling. He has been previously well, and inspection of his immunization records reveals that all are up-to-date for his age. On examination, you note that he appears very ill and prefers to sit leaning forward on his hands with his neck hyperextended. His voice is muffled. Which of the following is correct regarding his likely diagnosis?

(A) This patient likely has bacterial tracheitis and should be started on antistaphylococcal antibiotics.

(B) Racemic epinephrine should be immediately administered.

(C) Anesthesiology should be consulted and should visualize his airway and intubate him in a controlled environment (e.g., operating room).

(D) An anterior-posterior radiograph of the neck will show a “steeple sign.”

(E) The throat should be examined with a tongue depressor to rule out retropharyngeal abscess.

  1. A 6-week-old female infant presents with increased work of breathing and a staccato-type cough for 3 days. On physical examination you note a temperature of 98.8°F (37.1°C), a respiratory rate of 60 breaths/min, and bilateral conjunctival erythema. The lungs are clear except for mild wheezing at the bilateral lung bases. Which of the following is correct regarding her likely diagnosis?

(A) Pneumonia is unlikely given the absence of fever, and therefore a noninfectious cause of the patient's symptoms should be sought.

(B) Eosinophilia will be found on complete blood count.

(C) Blood culture will be positive in 25% of cases.

(D) Corticosteroids are indicated and will improve the patient's clinical course.

(E) Ribavirin should be considered.

P.279

 

  1. A 9-year-old girl with asthma is brought to the office for the first time. On average, she uses her albuterol inhaler three times per week, but for the past 10 days, she has been wheezing both day and night and is using the inhaler three to four times per day. On examination, you note diffuse wheezing and moderate subcostal retractions. Which of the following is the next step in management?

(A) Order a chest radiograph to assess for pneumonia.

(B) Refer her to an allergist for allergen immunotherapy.

(C) Start an oral leukotriene modifier.

(D) Start a low-dose inhaled corticosteroid.

(E) Start a 5-day course of systemic corticosteroids.

The response options for statements 11 and 12 are the same. You will be required to select one answer for each statement in the set.

For each description of a patient with asthma, select the most appropriate pharmacologic therapy.

  1. A 12-year-old girl with daily wheezing and nighttime symptoms two times per week.

(A) Short-acting inhaled β2-agonist for symptom relief plus medium-dose inhaled corticosteroid

(B) Short-acting inhaled β2-agonist for symptom relief

(C) Short-acting inhaled β2-agonist for symptom relief plus long-acting β2-agonist and high-dose inhaled corticosteroid

(D) Short-acting inhaled β2-agonist for symptom relief plus low-dose inhaled corticosteroid

(E) Inhaled cromolyn sodium for symptom relief

  1. A 10-year-old boy with wheezing every other month associated with cold symptoms.

(A) Short-acting inhaled β2-agonist for symptom relief plus medium-dose inhaled corticosteroid

(B) Short-acting inhaled β2-agonist for symptom relief

(C) Short-acting inhaled β2-agonist for symptom relief plus long-acting β2-agonist and high-dose inhaled corticosteroid

(D) Short-acting inhaled β2-agonist for symptom relief plus low-dose inhaled corticosteroid

(E) Inhaled cromolyn sodium for symptom relief

P.280

 

Answers and Explanations

  1. The answer is A[III.B]. Croup is the most common cause of acute stridor and cough in toddlers, and parainfluenza virus causes the majority of these infections. Foreign body aspiration may cause stridor or cough and should be considered as a cause because in as many as 50% of foreign body aspirations, choking is not witnessed. Albuterol plays no role in management of croup unless associated asthma or wheezing is present. An anterior-posterior radiograph of the neck will show a “steeple sign” characteristic of subglottic narrowing; however, a “thumbprint sign” is associated with epiglottitis. Antibiotics are not indicated for croup.
  2. The answer is C[III.D.3, 4, 5, 6]. This patient's clinical features are consistent with bronchiolitis, a lower respiratory tract infection. Supportive care is the most effective management, although inhaled albuterol and racemic epinephrine may have some benefit for some patients. Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis. Chest radiography usually demonstrates hyperinflation and atelectasis. Chlamydia trachomatispneumonia generally occurs in a young infant, 1–3 months of age, and would be very unlikely in a 5-month-old infant. Erythromycin is not effective for bronchiolitis. Evidence for benefit of ribavirin in the treatment of bronchiolitis is lacking, and ribavirin should only be considered for severely ill infants.
  3. The answer is E[Table 9-2 and III.E.3]. The most common cause of pneumonia in older children and adolescents is infection with Mycoplasma pneumoniaeand Chlamydia pneumoniae. Pneumonia in immunocompromised patients may be caused by Pneumocystis carinii. Although pneumonia as a result of Staphylococcus aureus may occur in adolescents, it is less common than Mycoplasma and Chlamydia infection. Group B streptococcus is an organism unique to the neonatal period. Haemophilus influenzae type b (HIB) typically causes pneumonia in infants and toddlers, although the incidence has declined markedly as a result of effective vaccination against HIB.
  4. The answer is B[IV.B.3, 4, 5, IV.B.7, Table 9-5]. The likely diagnosis is cystic fibrosis (CF). Lung disease eventually develops in all individuals with CF; the lungs are initially colonized with Staphylococcus aureusand subsequently with Pseudomonas aeruginosa. Twenty percent of neonates with CF present with meconium ileus, an impaction of inspissated meconium that causes congenital intestinal obstruction. Classic electrolytes reveal a hyponatremic, hypochloremic, hypokalemic metabolic alkalosis. Pulmonary function studies demonstrate decreased respiratory flow rates consistent with obstructive lung disease early in the disease process. Later, restrictive lung disease patterns are present. The autosomal recessive inheritance of CF means that each subsequent sibling has a 25% chance of having the disease. Pathophysiology involves an altered ion-channel regulator (CFTR) protein, resulting in abnormal sodium and chloride transport in epithelial cells.
  5. The answer is D[IV.B.7]. Pancreatic insufficiency and malabsorption are very common and require pancreatic enzyme replacement and the administration of fat-soluble vitamins (vitamins A, D, E, and K). Nutritional support is very important as patients commonly have failure to thrive with difficulty gaining weight, and high-calorie diets are therefore prescribed. Broad-spectrum antibiotics should be used for treatment of pulmonary exacerbations. Other effective modalities in CF are bronchodilators for wheezing and aggressive pulmonary toilet, including chest physical therapy.
  6. The answer is A[IV.C]. Prematurity and barotrauma from prolonged mechanical ventilation are significant risk factors for the development of bronchopulmonary dysplasia or chronic lung disease. Lung injury typically causes a combination of obstructive (from dysplastic and narrowed airways) and restrictive (from lung tissue fibrosis) lung disease. To meet their metabolic demands and facilitate growth, patients require very high caloric intakes. Pulmonary disease improves with time and lung growth, although chest radiographs may remain abnormal for years. Development is often delayed in children with chronic lung disease.

P.281

 

  1. The answer is D[IV.E]. This patient had an apparent life-threatening event (ALTE). The evaluation of an ALTE should include attempts to identify an underlying cause, and workup may include an electroencephalogram to rule out a seizure disorder, an electrocardiogram to rule out a dysrhythmia such as long QT syndrome, electrolytes, a barium esophagogram or pH probe study to rule out gastroesophageal reflux disease, and a sleep study. An ALTE is not a presentation of cystic fibrosis (CF), and therefore a sweat chloride test is not indicated. Patients with CF generally present with failure to thrive, repeated pulmonary infections, or evidence of pancreatic insufficiency. After an ALTE, many experts recommend observation and monitoring of the infant in the hospital and, sometimes, discharge home on an apnea monitor. However, the effectiveness of an apnea monitor in preventing sudden infant death syndrome has not been established. The patient's presentation is not consistent with periodic breathing, which is defined as a breathing pattern with three or more respiratory pauses lasting 3 seconds each, with less than 20 seconds of normal respirations in between.
  2. The answer is C[III.A.7]. This patient's presentation with fever, toxic appearance, muffled speech, tripod positioning when seated, drooling, and neck hyperextension all point to epiglottitis as a possible diagnosis. Epiglottitis is now a very uncommon infection as a result of the successful immunization of children against Haemophilus influenzaetype b (HIB); however, epiglottitis may still occur secondary to infection with streptococcal and staphylococcal species. Management includes avoidance of excessive stimulation, including examination of the pharynx with a tongue depressor, because this may induce respiratory distress. Evaluation of the airway and intubation by experienced personnel in a controlled setting is necessary. Racemic epinephrine is not effective in epiglottitis. A “steeple sign” on a radiograph of the neck is consistent with the diagnosis of croup, not epiglottitis (which demonstrates a “thumbprint sign” on lateral radiograph of the neck). Bacterial tracheitis presents with fever and stridor (rather than a muffled voice), and drooling and neck hyperextension are unlikely to be present.
  3. The answer is B[III.E.3, III.E.4.c, Table 9-2]. This patient's clinical features point to a likely diagnosis of pneumonia secondary to infection with Chlamydia trachomatis, which is a common cause of pneumonia in patients 1–3 months of age. Patients are afebrile, have a characteristic staccato-type cough, and may have a history of conjunctivitis (in 50% of cases). Diagnosis is suggested by the presence of elevated eosinophils on complete blood count. Blood cultures are not positive in this infection. Management includes oral erythromycin or azithromycin. Neither corticosteroids nor ribavirin are effective treatments for C. trachomatispneumonia.
  4. The answer is E[IV.A.7, Table 9-4]. This patient presents with a moderate exacerbation of her chronic asthma and therefore would benefit from a 5- to 10-day course of systemic corticosteroids. Both inhaled corticosteroids and leukotriene inhibitors are effective management options for the prevention and long-term management of asthma, and these agents should be considered for this patient after the systemic corticosteroids. Allergen immunotherapy may also be beneficial but would not be the initial step in management. Pneumonia is unlikely, and therefore a chest radiograph is not indicated.

11 and 12. The answers are A and B, respectively [Table 9-4 and IV.A.7]. Asthma is graded on a severity scale on the basis of the frequency of asthma symptoms during the day and night and also on pulmonary function testing. The 12-year-old girl's asthma would be characterized as moderate persistent asthma because of the presence of daily symptoms and nighttime wheezing more often than once per week. The best treatment for moderate persistent asthma is medium-dose inhaled corticosteroids added to as needed inhaled β2-agonists. The 10-year-old boy's asthma would be characterized as intermittent asthma because his asthma symptoms occur twice weekly or less, and nighttime symptoms twice monthly or less. The best treatment for intermittent asthma is short-acting inhaled β2-agonist medication.