Bullous lung disease

Learning objectives

Bullous lung disease is an uncommon cause of respiratory distress
Characterized by the development of bullae within the lung parenchyma
A bulla is a permanent, air-filled space within the lung parenchyma that is at least 1 cm in size and has a thin or poorly defined wall
The term giant bulla is used for bullae that occupy at least 30 percent of a hemithorax
Bullae do not take part in gas exchange and cause hypoxia and dyspnea
Bullae are to be distinguished from other air-filled spaces within the lung:
- Blebs are air-filled collections within the layers of the visceral pleura and are <1 cm in diameter
- Cysts are round, well-circumscribed collections that have an epithelial or fibrous lining
- Cavities are usually thick-walled collections formed by focal necrosis within a consolidation, mass, or nodule
- Pneumatoceles are temporary tents in the lung parenchyma that usually arise from blunt trauma or over-distension of the lung
Bullae grow in size over time
If positive pressure is used, the intra-bulla pressure will rise in relation to surrounding lung regions with a concomitant risk of hyperinflation and rupture
Bulla rupture could be life-threatening due to hemodynamic collapse from a tension pneumothorax or inadequate ventilation due to a resultant bronchopleural fistula

Shortness of breath or chest tightness, particularly with exertion
Cough
Sputum production
Abdominal fullness or bloating, usually associated with severe obstruction and prominent air-trapping on pulmonary function testing

If symptoms are absent, bullae do not require intervention
Perform surgical extraction when the patient has incapacitating dyspnea or for patients who have complications related to bullous diseases, such as infection or pneumothorax