Case Presentation: A 35 year old female with asthma, endometriosis and three prior right sided pneumothoraces presented to the emergency department with dyspnea and chest pain without recent trauma, and was again admitted with right sided pneumothorax. Her exam was notable for thin, young adult female, non-smoker, with decreased breath sounds on the right. Her lab workup to include alpha-1-antitrypsin, COVID PCR, CBC; was only notable for mild anemia with hemoglobin of 10.9. A pigtail catheter was placed in the emergency department for decompression.She was evaluated by cardiothoracic surgery who recommended she undergo VATS pleurodesis for definitive treatment at which time endometrial deposits were noted in the central tendon of the diaphragm. Once she had recovered from her procedure she was discharged home and has not been readmitted with recurrent pneumothorax.
Discussion: Catamenial pneumothorax is associated with endometriosis which is caused by the development of endometrial-like glands and stroma outside of the uterus. Although the most common site of endometriosis is within the pelvic cavity, the second most common location of these aberrant endometrial glands is within the thoracic cavity. It has been cited that pneumothorax occurs in up to 72% of women with known thoracic endometriosis. The gold standard for the diagnosis of thoracic endometriosis is the histological triad of endometrial glands, stroma, and hemosiderin laden macrophages. However, in thoracic endometriosis, endometrial glands are often absent, with 56% of cases showing “stromal only” endometriosis in the thoracic cavity.Spontaneous pneumothorax is not uncommon in younger patients and it is important to differentiate between primary (absence of underlying lung disease) or secondary (presence of underlying lung disease). Primary pneumothorax typically occurs within a younger population and has a variable recurrence rate from 17-54%. Catamenial pneumothorax is considered a subset of primary pneumothorax, which most commonly presents in young, reproductive age women and typically occurs within 72 hours prior to or after the start of the menstrual cycle, as was the case with our patient. It is thought that catamenial pneumothorax may account for 3-6% of spontaneous pneumothorax cases. Primary management of primary spontaneous pneumothorax includes aspiration of air from the thoracic cavity, VATS, and chemical pleurodesis. A few options that are unique to catamenial pneumothorax are menstrual cycle cessation through hormonal contraceptives and even salpingo oophorectomy in severe cases. Interestingly, prior case studies have found high rates of recurrent pneumothorax even after surgical intervention, however there is still limited data regarding alternative methods that may yield longer periods without recurrence.
Conclusions: Spontaneous pneumothorax is a relatively common problem encountered in the hospital and management is often straightforward. However, in reproductive age female patients, a thorough gynecologic history may help uncover endometriosis and potentially catamenial pneumothorax. If identified, these patients can be offered hormonal contraception to help suppress their menstrual cycles with the goal of diminishing pneumothorax recurrence. This is a cost-effective alternative to invasive surgical intervention and if successful can reduce morbidity in this patient population.