Case Files Pediatrics, (LANGE Case Files) 4th Ed.

CASE 10

A 4-year-old boy has a 2-day history of runny nose, productive cough, and wheezing. Subjective fever and decreased appetite also were noted today. He has no known cardiorespiratory disease, and his immunizations are current. His two younger siblings are recovering from “chest colds.” On examination, he is febrile to 103.2°F (39.6°C), with a respiratory rate of 22 breaths/min. His examination is remarkable for congested nares, clear rhinorrhea, coarse breaths sounds in all lung fields, and bibasilar end-expiratory wheezes.

Image What is the most likely diagnosis?

Image What is the next step in evaluation?

ANSWERS TO CASE 10: Pneumonia

Summary: A toddler presents with cough, fever, and an abnormal chest examination.

• Most likely diagnosis: Pneumonia.

• Next step in evaluation: A chest x-ray (CXR) often is indicated to ascertain if radiographic changes support clinical findings. In addition to chest radiography, pulse oximetry and selected laboratory tests (complete blood count [CBC], blood culture, and nasal wash for selected viral antigens) may help elucidate the etiology and extent of infection, as well as direct possible antimicrobial therapy.

ANALYSIS

Objectives

1. Describe the etiologies of pneumonia and their age predilections.

2. Describe various clinical and radiographic findings in pneumonia.

3. Describe the evaluation and treatment of pneumonia.

Considerations

The most important initial goal in managing this patient is to ensure adequacy of the ABCs (maintaining the Airway, controlling the Breathing, and ensuring adequate Circulation). A patient with pneumonia may present with varying degrees of respiratory compromise. Oxygen may be required, and in severe cases respiratory failure may be imminent, necessitating intubation and mechanical ventilation. The patient with pneumonia and sepsis also may have evidence of circulatory failure (septic shock) and require vigorous fluid resuscitation. After the basics of resuscitation have been achieved, further evaluation and management can be initiated.

APPROACH TO:

The Child with Pneumonia

DEFINITIONS

RALES: Wet or “crackly” inspiratory breath sounds due to alveolar fluid or debris; usually heard in pneumonia or congestive heart failure (CHF).

PLEURAL RUB: Inspiratory and expiratory “rubbing” or scratching breath sounds heard when inflamed visceral and parietal pleurae come together.

STACCATO COUGH: Coughing spells with quiet intervals, often heard in pertussis and chlamydial pneumonia.

PLEURAL EFFUSION: Fluid accumulation in the pleural space; may be associated with chest pain or dyspnea; can be transudate or exudate depending on results of fluid analysis for protein and lactate dehydrogenase; origins include cardiovascular (congestive heart failure), infectious (mycobacterial pneumonia), and malignant (lymphoma).

EMPYEMA: Purulent infection in the pleural space; may be associated with chest pain, dyspnea, or fever; usually seen in conjunction with bacterial pneumonia or pulmonary abscess.

PULSE OXIMETRY:Noninvasive estimation of arterial oxyhemoglobin concentration (SPO2) using select wavelengths of light.

CLINICAL APPROACH

Pneumonia or lower respiratory tract infection (LRTI) is a diagnosis made clinically and radiographically. The typical pediatric patient with pneumonia may have traditional findings (fever, cough, tachypnea, and toxicity) or very few signs, depending on the organism involved and the patient’s age and health status.

Pathophysiology

Lower respiratory tract infection (LRTI) typically begins with organism acquisition via inhalation of infected droplets or contact with a contaminated surface. Depending on the organism, spread to distal airways occurs over varying intervals. Bacterial infection typically progresses rapidly over a few days; viral pneumonia may develop more gradually. With infection progression, an inflammatory cascade ensues with airways affected by humoral and cellular mediators. The resulting milieu adversely affects ventilation–perfusion, and respiratory symptoms develop.

Clinical and Radiologic Findings

The pneumonia process may produce few findings or may present with increased work of breathing manifested as nasal flaring, accessory muscle use, or tachypnea, the latter being a relatively sensitive indicator of pneumonia. Associated symptoms may include malaise, headache, abdominal pain, nausea, or emesis. Toxicity can develop, especially in bacterial pneumonia. Fever is not a constant finding. Subtle temperature instability may be noted in neonatal pneumonia. Clinically, pneumonia can be associated with decreased or abnormal breathing (rales or wheezing). Chest examination may be equivocal, especially in the neonate. Hypoxia can be seen. Pneumonia complications (pleural effusion) may be identified by finding localized decreased breath sounds or rubs.

Radiographic findings in LRTI may be limited, nonexistent, or lag the clinical symptoms, especially in the dehydrated patient. Findings may include single or multilobar consolidation (pneumococcal or staphylococcal pneumonia), air trapping with a flattened diaphragm (viral pneumonia with bronchospasm), or perihilar lymphadenopathy (mycobacterial pneumonia). Alternatively, an interstitial pattern may predominate (mycoplasmal pneumonia). Finally, pleural effusion and abscess formation are more consistent with bacterial infection.

Causative Organisms

LRTI occurs more frequently in the fall and winter and with greater frequency in younger patients, especially those in group environments (large households, day care facilities, and elementary schools). When all age groups are considered, approximately 60% of pediatric pneumonias are bacterial in origin, with pneumococcus topping the list. Viruses (respiratory syncytial virus [RSV], adenovirus, influenza, parainfluenza, enteric cytopathic human orphan [ECHO] virus, and coxsackie virus) run a close second.

Identifying an organism in pediatric pneumonia may prove difficult; causative organisms are identified in only 40% to 80% of cases. Routine culturing of the nasopharynx (poor sensitivity/specificity) or sputum (difficulty obtaining specimens in young patients) usually is not performed. Thus, diagnosis and treatment usually are directed by a patient’s symptoms, physical and radiographic findings, and age.

In the first few days of life, Enterobacteriaceae and group B Streptococcus (GBS) are the primary bacterial etiologies; other possibilities include Staphylococcus aureus, Streptococcus pneumoniae(pneumococcus), and Listeria monocytogenes. In the newborn with pneumonia, broad-spectrum antimicrobials (ampicillin with either gentamicin or cefotaxime) are customarily prescribed. During the first few months of life, Chlamydia trachomatis is a possibility, particularly in the infant with staccato cough and tachypnea, with or without conjunctivitis or known maternal chlamydia history. These infants also may have eosinophilia, and bilateral infiltrates with hyperinflation on chest radiograph; treatment is erythromycin. Viral etiologies include herpes simplex virus (HSV), enterovirus, influenza, and RSV; of these, HSV is the most concerning and prevalent viral pneumonia in the first few days of life. Intravenous acyclovir is an important consideration if HSV is suspected.

Beyond the newborn period and through approximately 5 years of age, viral pneumonia is common; adenovirus, rhinovirus, RSV, influenza, and parainfluenza are possibilities. Bacterial etiologies include pneumococcus and nontypeable Haemophilus influenzae. Patients with nasal and chest congestion with increased work of breathing, wheezing, and hypoxemia regularly present to the emergency room during the winter months and are admitted for observation, oxygen, and bronchodilator therapies. The diagnosis of a viral process may be made clinically or with CXR findings (perihilar interstitial infiltrates). Nucleic acid polymerase chain reaction (PCR) amplification of secretions from a nasal swab or wash often is performed to confirm a viral etiology. A mixed viral and bacterial pneumonia can be present in approximately 20% of patients. Antibacterial coverage should be considered if the clinical scenario, examination, or x-ray findings suggest bacterial infection.

The pediatric patient older than approximately 5 years of age with LRTI typically has Mycoplasma. However, most of the viral and bacterial etiologies previously listed are possible, except GBS and Listeria.Antibiotics in this age group are directed toward Mycoplasma and typical bacteria (pneumococcus). Treatment options include macrolides (azithromycin) or cephalosporins (ceftriaxone or cefuroxime).

Pneumonia in the intubated intensive care patient with central lines may be related to Pseudomonas aeruginosa or fungal species (Candida). Pseudomonas and Aspergillus are possibilities in the patient with chronic lung disease (cystic fibrosis). Varicella-zoster virus should be considered in the patient with typical skin findings and pneumonia; cytomegalovirus (CMV) if concomitant retinitis is present; Legionella pneumophila if the patient has been exposed to stagnant water; and Aspergillus if a patient has refractory asthma or a classic “fungal ball” on chest radiograph. Travel to the southwestern United States may expose patients to Coccidioides immitis, infected sheep or cattle to Coxiella brunetti, and spelunking or working on a farm east of the Rocky Mountains to Histoplasma capsulatum.

One important subset of LRTI is tuberculosis (TB). Mycobacterium tuberculosishas become more problematic over the past decade; multidrug resistance is increasingly seen. Patients may present with symptoms ranging from a traditional cough, bloody sputum, fever, and weight loss to subtle or nonspecific symptoms. A positive purified protein derivative (PPD) is defined by induration diameter in the context of a patient’s exposure history, radiographic findings, and immune status. For instance, 5-mm induration may be considered a “positive PPD” at 48 to 72 hours in a patient with confirmed exposure, abnormal chest radiograph, or immunodeficiency. This same measurement in an otherwise healthy child without exposures would not be considered positive. Possible sources for acid-fast bacilli for stain and culture (depending on the age of the patient) include sputum samples, first-morning gastric aspirates, cerebrospinal fluid, bronchial washes or biopsy obtained through bronchoscopy, and empyema fluid analysis or pleural biopsy if surgical intervention is required. Standard antituberculous therapy, while awaiting culture and sensitivities, includes isoniazid, rifampin, and pyrazinamide. For possible drug-resistant organisms, ethambutol can be added temporarily as long as visual acuity can be followed. The typical antibiotic course consists of an initial phase of approximately 2 months’ duration on three or four medications, followed by a continuation phase of 4 to 10 months on isoniazid and rifampin. Therapy for 9 to 12 months is recommended for CNS or disseminated TB. Ultimately, total therapy duration is dependent upon the extent of imaging abnormalities, resistance patterns, and results of follow-up sputum samples in the age-appropriate patient. Directly observed therapy should be routinely advised.

COMPREHENSION QUESTIONS

10.1 A 6-week-old boy, born by vaginal delivery after an uncomplicated term gestation, has experienced cough and “fast breathing” for 2 days. His mother relates that he has a 1-week history of nasal congestion and watery eye discharge, but no fever or change in appetite. He has a temperature of 99.4°F (37.4°C) and a respiratory rate of 44 breaths/min. He has nasal congestion, clear rhinorrhea, erythematous conjunctivae bilaterally, and watery, right eye discharge. His lungs demonstrate scattered crackles without wheezes. Which of the following is the most likely pathogen?

A. C trachomatis

B.L monocytogenes

C. Respiratory syncytial virus

D. Rhinovirus

E.S pneumoniae

10.2 A 2-year-old girl has increased work of breathing. Her father notes she has had cough and subjective fever over the past 3 days. She has been complaining that her “belly hurts” and has experienced one episode of posttussive emesis, but no diarrhea. Her immunizations are current, and she is otherwise healthy. Her temperature is 102°F (38.9°C). She is somnolent but easily aroused. Respirations are 28 breaths/min, and her examination is remarkable for decreased breath sounds at the left base posteriorly with prominent crackles. Which of the following acute interventions is the next best step in your evaluation?

A. Blood culture

B. Chest radiography

C. Pulse oximetry

D. Sputum culture

E. Viral nasal swab

10.3 You are evaluating a previously healthy 8-year-old boy with subjective fever, sore throat, and cough over the past week. There has been no rhinorrhea, emesis, or diarrhea, and his appetite is unchanged. According to your clinic records, his immunizations are current and his weight was at the 25th percentile on his examination 6 months ago. Today, he is noted at the 10th percentile for weight. He is a febrile, with clear nares and posterior oropharynx, and a normal respiratory effort. He has bilateral cervical and right supraclavicular lymphadenopathy. Chest auscultation is notable for diminished breath sounds at the left base. Beyond obtaining a chest radiograph, which of the following is the best next step in your evaluation?

A. Rapid strep throat swab

B. Viral nasal swab

C. PPD placement

D. Lymph node biopsy

E. Bordetella pertussis direct fluorescent antibody testing

10.4 A 13-year-old adolescent female complains of dry cough, slight fever, and fatigue over the past 2 weeks. She noted increased chest congestion and coughing yesterday when walking outside in the cold air. She denies nasal congestion, rhinorrhea, emesis, or diarrhea. Her mother declares her daughter is generally healthy with a history of only summertime allergies. Her vital signs, respiratory effort, and chest examination are normal. Which of the following is the most likely pathogen?

A. H influenzae

B. M pneumoniae

C. Respiratory syncytial virus

D. S aureus

E. S pneumoniae

ANSWERS

10.1 A. Cough and increased respiratory effort in an afebrile infant with eye discharge are consistent with Chlamydia. Transmission typically occurs during vaginal delivery. Approximately 25% of infants born to mothers with Chlamydia develop conjunctivitis; about half of these develop pneumonia. Most infants present with respiratory infection in the second month of life, but symptoms can be seen as early as the second week. Inner eyelid swabs are sent for PCR, and oral erythromycin or sulfisoxazole (latter only in infants older than 2 months of age) is given for 2 weeks for either conjunctivitis or pneumonia.

10.2 C. Tachypnea and lethargy are prominent in this patient with clinical pneumonia. Pulse oximetry should urgently be performed to ascertain whether oxygen is required. Sputum culturing is reasonable for an older patient who can produce sputum, but an adequate and diagnostically useful specimen can only be obtained from a 2-year-old by endotracheal aspirate or bronchoscopy. In this otherwise healthy toddler for whom concerns for atypical pneumonia are high, invasive maneuvers are not indicated. Viruses (RSV and adenovirus) are prominent at this age; one might consider performing a nasal swab for viral antigens. Abdominal pain, as noted in this question, can be seen as a presenting symptom in pneumonia, probably as a result of irritation of the diaphragm by pulmonary infection.

10.3 C. The scenario is typical for pediatric tuberculosis. Neck and perihilar or mediastinal lymphadenopathy and pulmonary or extrapulmonary manifestations can occur, with miliary disease and meningitis more common in infants and younger children. Fever, weight loss, and lower respiratory tract signs and symptoms (possible left pleural effusion in this patient) are archetypal TB findings. A purified protein derivative (PPD) (usually with control) should be placed, and consideration given to hospitalizing this patient in negative pressure isolation for further evaluation beyond PPD placement (pleurocentesis, bronchoalveolar lavage, gastric aspirates) and possible antituberculous treatment.

10.4 B. All of these findings are consistent with mycoplasmal infection (“walking pneumonia”). The incubation period for Mycoplasma is 5 to 7 days, and most symptoms are noted during the second to third week of infection. Hemolysis occurs as antibodies attach to red blood cells, prompting reticulocyte production. If necessary, nasopharyngeal aspirate for PCR or measurement of cold agglutinins may help aid in the diagnosis. Auscultatory and radiographic findings vary in this infection; a normal CXR or one with an interstitial pattern, effusion, or atelectasis could be seen.


CLINICAL PEARLS

Image The etiology of pneumonia varies according to the patient’s age. Neonates have the greatest risk of group B Streptococcus, toddlers are more likely to have respiratory syncytial virus, and adolescents usually contract Mycoplasma.

Image Efforts in tuberculosis management should be directed toward isolating an organism and obtaining sensitivities, thus allowing selection of the optimal antituberculous regimen.


REFERENCES

American Academy of Pediatrics. Tuberculosis. In: Pickering LK, ed. 2009 Red Book: Report of the Committee on Infectious Diseases. 28th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2009:680-701.

Kennedy WA. Disorders of the lungs and pleura. In: Osborn LM, DeWitt TG, First LR, Zenel JA, eds. Pediatrics. 1st ed. Philadelphia, PA: Elsevier-Mosby; 2005:803-818.

Moscona A, Murrell MT, Horga M, Burroughs M. Respiratory infections. In: Katz SL, Hotez PJ, Gerson AA, eds. Krugman’s Infectious Diseases of Children. 11th ed. Philadelphia, PA: Mosby; 2005:493-524.

Roosevelt GE. Acute inflammatory upper airway obstruction. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: WB Saunders; 2011:1445-1449.

Sandora TJ, Sectish TC. Pneumonia. In: Kliegman RM, Stanton BF, St. Geme JW, Schor NF, Behrman RE, eds. Nelson Textbook of Pediatrics. 19th ed. Philadelphia, PA: WB Saunders; 2011:1474-1479.