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Pneumonia, infection of the lower respiratory tract, is one of the leading causes of pediatric morbidity and mortality throughout the world. The etiologic agent, clinical presentation, and severity of illness vary greatly based on the age of the child. In neonates (age 0 to 30 days), group B streptococci and other gram-negative enteric bacteria are common pathogens. Pneumonia caused by Chlamydia trachomatis has largely been eliminated in developed countries, but should be considered when the mother had little or no prenatal care. In infants and toddlers (1 month to 2 years), respiratory syncytial virus (RSV), influenza virus, parainfluenza virus, and human metapneumovirus are some of the common viral pathogens. Streptococcus pneumoniae and Haemophilus influenzae are the most common bacterial pathogens. Pneumonia in children aged 2 to 5 years is most likely caused by respiratory viruses, followed by S. pneumoniae, H. influenzae, and Staphylococcus aureus. In children 5 to 13 years of age, Mycoplasma pneumoniae is the most likely etiology of community-acquired pneumonia followed by S. pneumoniae and Chlamydophila pneumoniae. Adolescents typically follow the same seasonal and epidemiologic patterns of healthy adults with community-acquired pneumonia.
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The clinical presentation of pneumonia varies with the age of the patient, although most pediatric patients will have some combination of fever, preceding viral illness, tachypnea, respiratory distress, rales, and diminished breath sounds. Tachypnea is the most sensitive finding in pediatric patients with pneumonia (see Table 71-1). Symptoms of pneumonia may be subtle in neonates and infants, but these patients may be more severely ill. Fever or hypothermia, apnea, tachypnea, poor oral intake, vomiting, lethargy, grunting, or shock may be present in these patients. In older children and teens, community-acquired pneumonia presents more similarly to adult patients with a viral prodrome, fever, cough, abnormal lung sounds, vomiting, pleuritic chest pain, tachypnea, or hypoxemia. In younger children, particularly with lower lobe pneumonias, abdominal pain may be a predominant complaint. The clinical manifestations of bacterial and viral pneumonias overlap in all age groups, making the clinical distinction very challenging.
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DIAGNOSIS AND DIFFERENTIAL
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For most pneumonias, the etiologic agent is never determined. The diagnosis of pneumonia should primarily be made on clinical grounds; chest radiography is not required and not considered the gold standard for diagnosis. Chest radiography is not 100% sensitive, nor specific for the diagnosis of pneumonia, and does not distinguish between bacterial or viral etiologies. The presence of fever plus tachypnea, decreased breath sounds, or fine crackles predicts ...