An infection or inflammatory condition affecting lung tissue, particularly the parts of the lungs involved in gas exchange.
Pneumonia can be caused by bacteria, viruses, fungi, and other infectious agents. Inflammation and fluid or other material within the affected lung areas can interfere with the movement of oxygen into the blood.
Symptoms may include cough, fever, difficulty breathing, chest discomfort, and fatigue, although presentation varies considerably. Pneumonia can range from mild illness to a life-threatening condition.
QUICK FACT
Pneumonia is not caused only by bacteria. Viruses and fungi can also cause pneumonia.
COMMONLY CONFUSED WITH
Bronchitis: Bronchitis primarily involves inflammation of the bronchi, whereas pneumonia involves infection and inflammation of lung tissue.
SEE ALSO