Pneumonia with lung abscess

Alternative names:

anaerobic pneumonia; aspiration of vomitus; aspiration pneumonia; necrotizing pneumonia; pyogenic pneumonia

Definition:

Aspiration pneumonia is an inflammation of the lungs and bronchial tubes caused by inhaling foreign material, usually food, drink, vomit, or secretions from the mouth into the lungs. This may progress to form a collection of pus in the lungs (lung abscess).

Causes, incidence, and risk factors:

Aspiration of foreign material (often the stomach contents) into the lung can be a result of disorders that affect normal swallowing, disorders of the esophagus (esophageal stricture, gastroesophageal reflux), or decreased or absent gag reflex ( in unconscious, or semi-conscious individuals). Old age, dental problems, use of sedative drugs, anesthesia, coma, and excessive alcohol consumption are also causing or contributing factors. The response of the lungs depends upon the characteristics and amount of the aspirated substance. The more acidic the material, the greater the degree of lung injury. Aspiration of gastric contents is one of the leading causes of adult respiratory distress syndrome (flooding of the lungs with fluid).

The injured lungs can become infected with multiple species of anaerobic bacteria or aerobic bacteria. A collection of pus, from white blood cells that have been carried to the area to fight infection and from the microorganisms causing the infection, forms in the lung. A protective membrane may form around the abscess. The incidence of pneumonia with lung abscess is 6 out of 100,000 people.