Definition of Aspiration pneumonia:

Aspiration pneumonia is inflammation of the lungs and airways to the lungs (bronchial tubes) from breathing in foreign material.

Aspiration pneumonia occurs when foreign materials (usually food, liquids, vomit, or fluids from the mouth) are breathed into the lungs or airways leading to the lungs.

This may lead to:

• A collection of pus in the lungs (lung abscess)
• Swelling and inflammation in the lung
• A lung infection (pneumonia)

Causes, incidence, and risk factors:

Risk factors for aspiration or breathing in of foreign material into the lungs are:

• Being less alert due to medicines, illness, or other reasons
• Coma
• Disorders of the esophagus, the tube that moves food from the mouth to the stomach (esophageal stricture, gastroesophageal reflux)
• Drinking large amounts of alcohol
• Medicine to put you into a deep sleep for surgery (general anesthesia)
• Old age
• Poor gag reflex in people who are not alert (unconscious or semi-conscious) after a stroke or brain injury
• Problems with swallowing

Acidic material that is breathed into the lungs can cause severe lung injury. However, it may not necessarily lead to pneumonia.