Community-acquired pneumonia

Community-acquired pneumonia (CAP) refers to pneumonia contracted by a person outside of the healthcare system. In contrast, hospital-acquired pneumonia (HAP) is seen in patients who are in a hospital or who have recently been hospitalized in the last 48 hours. Those who live in long-term care facilities or who had pneumonia after 48 hours of hospitalization for another cause are also classified as having CAP (they were previously designated as having HCAP (healthcare associated pneumonia)). CAP is common, affecting people of all ages, and its symptoms occur as a result of oxygen-absorbing areas of the lung (alveoli) becoming colonized by a pathogenic microorganism (such as bacteria, viruses or fungi). The resulting inflammation and tissue damage causes fluid to fill the alveoli, inhibiting lung function and causing the symptoms of the disease. Common symptoms of CAP include dyspnea, fever, chest pains and cough.

10% of those with CAP are hospitalized. The 30 day mortality for those hospitalized with CAP is 2.8% for adults younger than 60 and 26.8% for adults older than 60 with other medical conditions.

CAP, the most common type of pneumonia, is a leading cause of illness and death worldwide. Its causes include bacteria, viruses, fungi and parasites. CAP is diagnosed by assessing symptoms, performing a physical examination, by x-ray or by sputum examination. Some form of chest imaging, usually in the form of a chest x-ray, showing characteristic findings is required for the diagnosis. Most cases can be treated on an outpatient basis, but some patients with CAP require hospitalization. CAP is treated primarily with antibiotics, antivirals or antifungals depending on the confirmed or suspected microorganism pathogen. Some forms of CAP can be prevented by vaccination and by abstaining from tobacco products. Vaccination against influenza, Covid, respiratory syncytial virus and the pneumococcal conjugate vaccine can all prevent CAP.