A 31-year-old woman presents with three episodes of self-limiting right-sided chest pain and breathlessness occurring exclusively within 24 hours of onset of menstruation. Chest radiograph during an episode shows a small right pneumothorax. She has a history of stage III endometriosis. The MOST likely diagnosis is:

• A Pulmonary embolism
• B Primary spontaneous pneumothorax
• C Catamenial angina
• D Thoracic endometriosis syndrome ✓

Explanation

Thoracic endometriosis syndrome encompasses catamenial pneumothorax (the most frequent form, right-sided in over 90 percent of cases), haemothorax, catamenial haemoptysis and lung nodules. Symptoms cluster within 24 to 72 hours of menstruation, driven by cyclical implant activity or fenestrations in the diaphragm allowing peritoneal air passage. Primary spontaneous pneumothorax is unrelated to menses and typically apical in tall young men. Pulmonary embolism gives persistent rather than strictly catamenial symptoms.

Reference: Berek and Novak's Gynecology, 16th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.