Pneumonia is one of the top ten causes of death: number six. It is also the number one cause of death from infection. Respiratory diseases account for approximately 10% of pediatric ER visits and 20% of pediatric admissions. One way to stratify the patients is how or why they acquired the infection: community acquired pneumonia (CAP,) nosocomial, or due to being in an immunocompromised state.

The number one cause of CAP is Streptococcus pneumoniae in children less than five years old. It's also associated with otitis media and sinusitis. The most common other causes of CAP are Mycoplasma pneumoniae, also known as walking pneumonia and Chlamydia pneumoniae. These two may be more common in children older than five years old, but when disease severity is taken into consideration, Streptococcus pneumoniae is again number one for severe cases of pneumonia in children regardless of age.

Pulmonary infections are the number one reason for obtaining a chest radiograph, and it is often described as the reference standard. You may or may not be able to see consolidation with air bronchograms, and pleural effusions can be seen in at least ten percent of patients with pneumonia.

CT studies may help to better characterize complex pneumonias or complications of pneumonia. CT may also help to detect underlying disease, and may also be useful in distinguishing a lung abscess from empyema.