Respiratory infections: community-acquired pneumonia.

Pneumonia causes substantial morbidity and mortality. Older age, suppressed immune function, and certain drugs increase the risk of community-acquired pneumonia (CAP), whereas adequate dental care and high socioeconomic status decrease the risk. For patients without other significant cardiopulmonary disease, the diagnosis of pneumonia can be straightforward. Common symptoms include fever, chills, pleuritic chest pain, and a cough with mucopurulent sputum. Bacterial and viral infections are the most common etiologies. Fungal and parasitic etiologies are less common. Illness severity scores and new diagnostic methods, including procalcitonin, proadrenomedullin, and bacterial diagnostic testing, are being used increasingly for CAP diagnosis. Antibiotic selection and treatment duration for CAP have become more standardized to decrease rates of bacterial antibiotic resistance. Still, CAP causes significant expense in human life and cost expenditures worldwide.