Community-acquired pneumonia (
CAP) refers to
pneumonia (any of several lung
diseases) contracted by a person with little contact with the healthcare system. The chief difference between
hospital-acquired pneumonia (HAP) and CAP is that patients with HAP live in long-term care facilities or have recently visited a hospital. CAP is common, affecting people of all ages, and its symptoms occur as a result of
oxygen-absorbing areas of the lung (
alveoli) filling with fluid. This inhibits lung function, causing
dyspnea,
fever,
chest pains and
cough.