2020 Nov 21. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan–.
The word "pneumonia" takes its origin from the ancient Greek word "pneumon," which means "lung," so the word "pneumonia" becomes "lung disease." Medically it is an inflammation of one or both lungs' parenchyma that is more often, but not always, caused by infections. The many causes of pneumonia include bacteria, viruses, fungi, and parasites. This article will focus on bacterial pneumonia, as it is the major cause of morbidity and mortality. According to the new classification of pneumonia, there are four categories: community-acquired (CAP), hospital-acquired (HAP), healthcare-associated (HCAP) and ventilator-associated pneumonia (VAP).
Types of Bacterial Pneumonia
CAP: The acute infection of lung tissue in a patient who has acquired it from the community or within 48 hours of the hospital admission.
HAP: The acute infection of lung tissue in a non-intubated patient that develops after 48 hours of hospitalization.
VAP: A type of nosocomial infection of lung tissue that usually develops 48 hours or longer after intubation for mechanical ventilation.
HCAP: The acute infection of lung tissue acquired from healthcare facilities such as nursing homes, dialysis centers, and outpatient clinics or from a patient with a history of hospitalization within the past three months.
Some articles include both HAP and VAP under the category of HCAP, so defining HCAP is problematic and controversial.