Lung Abscess Health Article

Definition

Lung abscess is an acute or chronic infection of the lung, marked by a localized collection of pus, inflammation, and destruction of tissue.

Description

Lung abscess is the end result of a number of different disease processes ranging from fungal and bacterial infections to cancer. It can affect anyone at any age. Patients who are most vulnerable include those weakened by cancer and other chronic diseases; patients with a history of substance abuse, diabetes, epilepsy, or poor dental hygiene; patients who have recently had operations under anesthesia; and stroke patients. In children, the most vulnerable patients are those with weakened immune systems, malnutrition, or blunt injuries to the chest.

Causes and symptoms

The immediate cause of most lung abscesses is infection caused by bacteria. About 65% of these infections are produced by anaerobes, which are bacteria that do not need air or oxygen to live. The remaining cases are caused by a mixture of anaerobic and aerobic (air breathing) bacteria. When the bacteria arrive in the lung, they are engulfed or eaten by special cells called phagocytes. The phagocytes release chemicals that contribute to inflammation and eventual necrosis, or death, of a part of the lung tissue. There are several different ways that bacteria can get into the lung.

Aspiration

Aspiration refers to the accidental inhalation of material from the mouth or throat into the airway and lungs. It is responsible for about 50% of cases of lung abscess. The human mouth and gums contain large numbers of anaerobic bacteria; patients with periodontal disease or poor oral hygiene have higher concentrations of these organisms. Aspiration is most likely to occur in patients who are unconscious or semi-conscious due to anesthesia, seizures, alcohol and drug abuse, or stroke. Patients who have problems swallowing or coughing, or who have nasogastric tubes in place are also at risk of aspiration.

Bronchial obstruction

The bronchi are the two branches of the windpipe that lead into the lungs. If they are blocked by tissue swelling, cancerous tumors, or foreign objects, a lung abscess may form from infection trapped behind the blockage.