Catamenial pneumothorax

Specialty: Gynecology and breast.

• Menstrual recurrent pulmonary collapse
• female cyclic pneumothorax
• thoracic endometriosis syndrome

Why it occurs

• Pleural or diaphragmatic endometriosis (implants suffer necrosis and cyclical peeling, opening communications between the peritoneal/alveolar and pleural spaces)
• Congenital diaphragmatic microperforations associated with transperitoneal migration of gas through the fallopian tubes during menstruation
• Passage of uterine air bubbles that ascend through the tubes and migrate through defects in the right diaphragm (90-95% of cases occur in the right lung)

Initial workup

Chest x-ray with immediate forced expiration to diagnose and quantify the degree of lung collapse. High-resolution chest CT to detect associated diaphragmatic nodules or subpleural bullae. Diagnostic and therapeutic video thoracoscopy (VATS) to visualize pleural endometriotic implants (typical brown or bluish color) and perforations in the hemidiaphragm.

Standard management

• There is no exclusive medical treatment for recurrent catamenial pneumothorax. Initial treatment consists of placement of a pleural drainage tube if the collapse is clinically significant (>20% lung volume). Adjuvant medical treatment with GnRH analogs (such as Leuprorelin 3.75 mg/month) uninterrupted for 6-12 months after VATS to prevent recurrences (note: optimal definitive surgical management requires excision of diaphragmatic endometriotic foci plus talc pleurodesis or pleural mechanical abrasion).