Community-acquired pneumonia.

Community-acquired pneumonia (CAP) remains an important cause of morbidity and mortality. Streptococcus pneumoniae is the most common pathogen and respiratory syncitial virus the most important viral pathogen in children. The role of urinary antigen testing and PCR for the diagnosis forS. pneumoniae infection has been an important adjunct to clinical examination, showing good sensitivity and specificity. Host-related immune responses play an important role in defining the severity of illness. Other than the use of Activated Protein C and immunization, the clinical use of therapies designed to modulate these abnormal responses remains largely experimental. The 7-valent vaccine represents a major advance in the prevention of invasive pneumococcal disease. The importance of effective triage and the deleterious effects of deviation from protocols are underscored. Continuous positive pressure ventilation and noninvasive mechanical ventilation are available as options for respiratory support in cases of severe CAP and require further evaluation.