2020 Aug 15. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–.
The severe form of acute lower respiratory tract infection that affects the pulmonary parenchyma in one or both lungs is known as pneumonia. It is a common disease and a potentially serious infectious disease with considerable morbidity and mortality. Pneumonia is the sixth leading cause of death and the only infectious disease in the top ten causes of death in the United States.
Pneumonia can be classified into 2 types based on how the infection is acquired:
Community-acquired pneumonia is diagnosed in non-hospitalized patients or a previously ambulatory patient within 48 hours after admission to the hospital. CAP is further divided into "typical" and "atypical."
HAP develops more than 48 hours after hospital admission. Patients who are mechanically ventilated for more than 48 hours after endotracheal intubation can develop pneumonia known as VAP. HCAP occurs in ambulatory patients who are not hospitalized and have had extensive healthcare contact within the last 3 months.