Cystic Swellings of the Posterior Triangle: Pneumatoceles

Abstract

Pulmonary pneumatoceles are thin-walled, air-filled cysts that develop within the lung parenchyma, usually in patients with emphysema, and as a sequela to acute pneumonia, commonly caused by Staphylococcus aureus. It may appear as a cystic swelling at the root of the neck; it increases in size with straining and cough and decreases with compression. Because they commonly develop as a complication of staphylococcal pneumonia, pneumatoceles are found more frequently in infants and young children. Noninfectious etiologies associated with pneumatocele formation include hydrocarbon ingestion, trauma, and positive pressure ventilation (PPV). Complications include the development of a tension pneumatocele (if air trapping continues), pneumothorax, and bronchopleural fistula. Other reported complications include pyopneumothorax, hemothorax, hemopneumothorax, pneumomediastinum, and secondary infection. A pneumatocele should be differentiated from a cystic or compressible mass on the lateral side of the neck. Treatment options include observation, antibiotic therapy, unilateral ventilation, high-frequency oscillation ventilation (HFOV), percutaneous needle decompression, decubitus positioning with the affected side down, selective intubation of the main bronchus on the uninvolved side, and injection of an intrapleural fibrin sealant. In general, a noncomplicated pneumatocele carries an excellent prognosis. The natural course is slow, but complete resolution with no further clinical sequelae usually occurs within 3 months to 2 years. This chapter discusses the epidemiology, etiology, pathophysiology, clinical picture, complications, investigations, differential diagnosis, treatment options, and prognosis of pneumatoceles.