Lung agenesis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Lung agenesis is defined as partial or complete failure of the lung to form with absence of the lung parenchyma, the bronchus and the pulmonary vessels.

The condition can be unilateral (compatible with life) or bilateral (fatal).

The trachea begins to develop at about 4 weeks of gestation as an outpouching from the foregut. Lung agenesis develops as a result of the bronchial analogue to develop into tow lung buds.

On the affected side, the pleural cavity is absent, and the healthy lung occupies the entire thorax. If a left lung develops, it is often trilobed.

Symptoms are due to due to tracheal compression and kinking of the trachea, shift of the mediastinal contents, posterior dislocation of the trachea as a result of a dislocated aortic arch and somtimes an associated truncus arteriosus.

• Truncus arteriosus ^[1][2][3]
• Dextrocardia with situs solitus may be present among patients with agenesis or hypoplasia of the right lung ^[4]

Lung agenesis is extremely rare and is observed in 1:15,000 autopsies.

There is a slight female preponderance.

The natural history is variable.

There can be kinking of the trachea and compression of the trachea by the aorta.

Although 50% of patients may die before the age of 5, the remainder of the individuals may be asymptomatic throughout their lives. Bilateral lung agenesis is a lethal anomaly.

• Cough
• Cyanosis
• Repeated respiratory infections
• Respiratory distress
• Stridor
• Tachypnea
• Wheezing

Symptoms are due to due to tracheal compression and kinking of the trachea, shift of the mediastinal contents, posterior dislocation of the trachea as a result of a dislocated aortic arch and somtimes an associated truncus arteriosus.

Indications for surgery include:

• Chronic unproductive cough
• Cyanosis
• Dyspnea
• Harsh breath sounds
• Tachypnea

The surgical procedure varies and includes aortopexy and diaphragmatic translocation which improve mediastinal shift and reduce heart rotation. Relief of tracheal compression is critical as is reduction in hyperinflation of the remaining lung.

Prophylactic surgery is not necessary.