Definition of Aspiration pneumonia:

Aspiration pneumonia is inflammation of the lungs and bronchial tubes due to breathing in a foreign material.

Causes, incidence, and risk factors:

Aspiration pneumonia is caused by inhaling foreign material (usually food, liquids, vomit, or secretions from the mouth) into the lungs. This may lead to an inflammatory reaction, a lung infection (pneumonia), or a collection of pus in the lungs (lung abscess).

Aspiration of foreign material (often the stomach contents) into the lung can occur with disorders that affect normal swallowing or disorders of the esophagus (esophageal stricture, gastroesophageal reflux). It also can be caused by a decreased or absent gag reflex in people who are not alert (conscious or semi-conscious).

Old age, dental problems, sedatives, anesthesia, coma, and excessive alcohol use can also lead to this problem. The more acidic the material breathed into the lungs, the more severe the lung injury -- although it may not necessarily lead to pneumonia.