In the United States, the incidence of community-acquired
pneumonia (CAP) is estimated to be between three and four million cases each year (2). It is the sixth most important cause of death, and the estimated cost of treatment, including patient care and lost wages, is $20 billion per year (4, 10). Treatment of pneumonia represents the largest consumption of antibiotics of all the diseases for which they are used. The disease is most prevalent in hospitalized patients, the elderly, and patients with compromised immune systems (e.g. AIDS patients). This paper will look at the epidemiology, etiology, clinical presentation, prognosis, treatment, and complications of pneumonia.
Pneumonia is defined as an infection of the lung parenchyma (6:1S). Pneumonia is now the leading cause of death due to infectious diseases in the United States (10). Community-acquired pneumonia frequently develops in the elderly, and 90 percent of deaths from CAP are in the aged (4:1295). Hospital-acquired pneumonia is now the second most common nosocomial infection in the Unites States and is associated with high morbidity, mortality, and increased hospital costs (6). Although approximately 77 percent of patients with pneumonia in the United States are treated in outpatient settings, the majority of pneumonia-related morbidity, mortality and health care expenditures occurs among persons who are hospitalized at some point during the illness (10:1709). Pneumonia cases have increased in recent years with the spread of HIV disease, the increase of homeless people crowded into unsanitary shelters, and the increase in numbers of elderly patients with chronic diseases living in nursing homes (4, 6).
CAP is usually caused by Streptococcus pneumoniae and other bacterial infections, but may be caused by other bacteria, Legionella, Mycobacterium tuberculosis, viruses, or fungi (6). A chest xray is the most definitive diagnostic test, and sputum cult...