Definition of Atelectasis:

Atelectasis is the collapse of part or all of a lung. It is caused by a blockage of the air passages (bronchus or bronchioles) or by pressure on the lung.

See also: Pneumothorax

Causes, incidence, and risk factors:

Risk factors for atelectasis include anesthesia, prolonged bed rest with few changes in position, shallow breathing, and underlying lung diseases. Mucus that plugs the airway, foreign objects (common in children) in the airway, and tumors that obstruct the airway may lead to atelectasis.

In an adult, small regions of atelectasis are usually not life-threatening. Unaffected parts of the lung can compensate for the loss of function in the affected area. Large-scale atelectasis may be life-threatening, especially in someone who has another lung disease or illness. In a baby or small child, lung collapse due to a mucus obstruction or other causes can be life-threatening.

Massive atelectasis may result in the collapse of a lung.