Community-acquired pneumonia (CAP) is a significant cause of morbidity and mortality in the United States. Most episodes occur after the sixth decade of life in patients with one or more chronic underlying diseases. Mortality from CAP averages 14% and has not decreased significantly since the early 1950s, despite advances in antibiotic and intensive care therapy.

Making the diagnosis of pneumonia is usually not difficult; deciding which patients should be admitted to the hospital and selecting appropriate therapy, however, can be challenging. The purpose of this chapter is to assist the clinician in deciding which patients should be admitted to the hospital and in selecting antibiotic therapy for CAP in immunocompetent patients who are not residents of chronic care facilities.

DIAGNOSIS AND TREATMENT

The diagnosis of pneumonia is suspected when one or more of the following clinical findings are present: cough, purulent sputum, dyspnea, pleuritic pain, fever, leukocytosis, chest auscultation findings consistent with pneumonia, or a new pulmonary inifiltrate. Once the diagnosis is made, the physician must decide whether hospitalization is necessary and, if hospitalized, whether intensive care unit (ICU) monitoring is advised.

A number of risk factors predict a complicated course (Table 31.1). Two published sets of criteria may assist the physician in deciding if hospitalization is necessary: the CURB-65 score from the British Thoracic Society and the Pneumonia Severity Index (PSI) from the Pneumonia Patient Outcomes Research Team (PORT).