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Midwestern University, Arizona College of Osteopathic Medicine
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A 34-year-old Caucasian female presents to the emergency department with acute onset breathing difficulty and right-sided, stabbing chest pain. Physical exam reveals decreased breath sounds over the right hemithorax and chest x-ray confirms a right pneumothorax. This is her third occurrence of right-sided pneumothoraces.
What can be considered a cause of recurrent pneumothoraces?
Upon further questioning, the patient’s past medical history consists of clinically diagnosed endometriosis treated with NSAIDs. She has no history of asthma, COPD, chest injury, or history of smoking. The patient has no history of Marfan’s syndrome, which may increase the risk of pneumothoraces due to apical blebs or bullae.
What is the significance of the patient’s history of endometriosis?
Although uncommon, endometrial tissue can be found in extra-pelvic sites, such as the lung. This presentation is known as thoracic endometriosis and is confirmed when endometrial tissue is identified on histological specimens. Up to 60% of cases will be associated with pelvic endometriosis.
How will thoracic endometriosis present?
Typically presents with cyclical episodes of chest pain and dyspnea beginning in the 3rd-4th decade of life, 2-3 days after the start of menstruation.
- Catamenial (occurring during menstruation) pneumothorax
- Catamenial hemoptysis
- Catamenial hemopneumothorax
There are several theories on how this can occur. Pathogenesis theories include retrograde menstruation entering the pleural space through lymphatic channels, diaphragmatic fenestrations, or hematogenous spread. During ovulation, the elevated prostaglandin F2 levels may lead to vasospasm and ischemia in the lung, resulting in subsequent alveolar rupture and pneumothorax. An additional theory, the anatomic model, suggests that the loss of the cervical mucus plug during menses leads to communication between the environment and the pleural space.
Why do the pneumothoraces most often present on the right side?
This is thought to be secondary to the peritoneal current in which fluid moves clockwise from the pelvis to the right paracolic gutter to the subphrenic space. Endometrial tissue is likely to follow this same pattern. The falciform ligament prevents further movement of fluid to the left.
How do we diagnose thoracic endometriosis?
Imaging modalities: Chest radiograph, MRI, CT, thoracentesis, and bronchoscopy.
Gold standard: Video-assisted thoracoscopic surgery (VATS).
- “Blueberry spots” or fenestrations in the central tendon of the diaphragm
- Endometrial lesions
- Bullae, blebs, scarring can be visualized
What are the treatment options?
- Oral contraceptives
- Non-Steroidal Anti-Inflammatory Drugs
- Progesterone therapy
- Danazol or GnRH agonists can be added as secondary agents
- VATS can be therapeutic and diagnostic
- Nezhat C, King LP, Paka C, Odegaard J, Beygui R. Bilateral Thoracic Endometriosis Affecting the Lung and Diaphragm. JSLS : Journal of the Society of Laparoendoscopic Surgeons. 2012;16(1):140-142. doi:10.4293/108680812X13291597716384.
- Azizad-Pinto P, Clarke D. Thoracic Endometriosis Syndrome: Case Report and Review of the Literature. The Permanente Journal. 2014;18(3):61-65. doi:10.7812/TPP/13-154.