Catamenial pneumothorax often involves endometriosis of the diaphragm, which causes the lung to collapse during a woman's menstrual cycle. It primarily effects women in their 30's and 40's, and is almost always right-sided. Many women afflicted with this condition have been previously diagnosed with pelvic endometriosis. Symptoms include chest and back pain, dizziness and shortness of breath, often accompanied by a crackling sound upon inhalation. Treatments include repair of holes in the diaphragm or removal of endometrial implants from the lung or pleura. Pleurodesis often accompanies video assisted thoracic surgery (VATS) to accomplish this repair. Additional treatments include hormonal suppression therapy using continuous birth control pills or gonadotropin releasing hormone agonists. Hysterectomy with the removal of the ovaries has also been a treatment of choice among patients and has shown some long term success. My twin sister and I were diagnosed with catamenial pneumothorax five years ago. We endured many thoracic treatments and continued to have collapses, until our hysterectomies. Since then, we have been collapse-free! Our experiences and additional information on this rare condition can be found at www.catamenial-pneumothorax.com Lizzieanddarcy