Description
Characteristic clinical findings of fever, cough, and rhonchi, together with a new infiltrate on chest films and documentation of a pathogen, establish a diagnosis of infectious pneumonia. Several factors have had an impact on the approach to diagnosis of community-acquired pneumonia by the primary care physician. These include the expanding number of possible pathogens as well as their increasing resistance to antimicrobial therapy. Although the clinical presentation may suggest a specific cause, findings often overlap too much for reliable identification of the specific agent on clinical grounds alone. Isolation of the microorganism or determination of the presence of a specific antigen or antibody is necessary. However, even after extensive studies are performed, the pathogen remains unidentified in 30% to 50% of cases. The primary care physician therefore needs to balance reasonable use of diagnostic tests with empirical therapy.