Definition of Aspiration pneumonia:

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

Causes, incidence, and risk factors:

Aspiration pneumonia is caused by breathing foreign materials (usually food, liquids, vomit, or fluids from the mouth) into the lungs. This may lead to:

• A collection of pus in the lungs (lung abscess)
• An inflammatory reaction
• A lung infection (pneumonia)

Aspiration of foreign material into the lungs can be caused by:

• Anesthesia
• Coma
• Decreased or absent gag reflex in people who are not alert (unconscious or semi-conscious)
• Dental problems
• Disorders that affect normal swallowing
• Disorders of the esophagus (esophageal stricture, gastroesophageal reflux)
• Excessive alcohol use
• Medications that affect alertness
• Old age
• Sedatives

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