Endometriosis is a condition where tissue similar to the lining of the uterus grows outside of the uterine cavity. Diaphragmatic endometriosis (DE) is a rare form of this disease, where this tissue implants on the diaphragm, the dome-shaped muscle separating the chest and abdominal cavities. This article clarifies the risks, complications, and management strategies associated with DE.
Understanding Diaphragmatic Endometriosis
Diaphragmatic endometriosis is estimated to affect between 0.6% and 1.5% of individuals undergoing surgery for endometriosis. When endometrial-like tissue implants on the diaphragm, the primary muscle involved in breathing, it responds to hormonal fluctuations like uterine tissue. This cyclical growth and bleeding cause inflammation and pain on the surface of the diaphragm.
This misplaced tissue is most frequently found on the right side of the diaphragm, often concealed behind the liver. Theories for how the tissue reaches the diaphragm include migration through the lymphatic system, spread through the bloodstream, or movement during retrograde menstruation. Characteristic symptoms involve pain that cycles with menstruation, often described as upper abdominal, chest, or pleuritic pain, which worsens with deep inhalation.
A common symptom leading to diagnosis is cyclical right shoulder pain, which is considered referred pain. This occurs because the phrenic nerve, which supplies the diaphragm, connects to nerves that supply the shoulder area. While the pain can be severe, small or superficial implants may be entirely asymptomatic, making diagnosis challenging.
Direct Mortality Risk
The direct mortality risk from endometriosis itself, including the diaphragmatic form, is extremely low. Endometriosis is not considered a primary, life-ending systemic disease like cancer. Fatal outcomes are not a direct result of the mere presence of the endometrial implants on the diaphragm.
The tissue growth causes chronic pain and impacts quality of life, but the disease process itself does not immediately cause organ failure. Death associated with endometriosis is almost always due to rare, secondary complications from advanced-stage disease affecting other organs, such as severe bowel obstruction or acute respiratory compromise. The risk is linked to the location and subsequent complications, not the underlying tissue growth alone.
Diaphragmatic endometriosis is a risk factor for specific acute emergencies where life-threatening potential emerges. However, with modern diagnostic tools and prompt medical intervention, the risk of death remains statistically rare. The focus shifts from the chronic disease to the acute mechanical complications it can trigger in the chest cavity.
Severe Complications and Medical Emergencies
The primary danger of diaphragmatic endometriosis lies in the acute complications it can cause within the chest cavity. The cyclical response of the tissue can lead to the formation of small holes, or fenestrations, in the diaphragm muscle. These defects allow air or blood to pass from the abdominal cavity into the pleural space surrounding the lungs.
The most recognized high-risk complication is Catamenial Pneumothorax, a collapsed lung that occurs within 72 hours of the onset of menstruation. This happens when air travels through the diaphragmatic defects, accumulating in the pleural space and causing the lung to collapse. This respiratory event requires immediate intervention to re-inflate the lung.
Another complication is Catamenial Hemothorax, which involves the accumulation of blood in the chest cavity from bleeding implants in the thoracic space. Both pneumothorax and hemothorax can lead to respiratory distress and, in severe cases, compression of the lung and heart, necessitating emergency care. These events, arising from the mechanical effects of the lesions, are why diaphragmatic endometriosis carries a serious risk.
Managing High-Risk Cases
Management, especially in high-risk cases that have experienced acute complications, focuses on definitive diagnosis and surgical excision. Specialized diagnostic imaging, such as magnetic resonance imaging (MRI) or computed tomography (CT) scans, help locate the lesions. However, a definitive diagnosis often requires visual confirmation during surgery.
The gold standard for treatment is the surgical removal of the lesions, often performed using minimally invasive techniques like laparoscopy or video-assisted thoracoscopic surgery (VATS). Since the disease can involve the full thickness of the diaphragm, this procedure may require a multidisciplinary team, including gynecological and cardiothoracic surgeons, to ensure complete removal and proper repair.
For full-thickness defects caused by deeper lesions, surgical repair is necessary, sometimes involving suturing or using a surgical patch or mesh to reinforce the muscle. Following excision, hormonal therapy is recommended to suppress any remaining microscopic disease and minimize recurrence risk. This combined surgical and medical approach mitigates the risk of life-threatening respiratory emergencies.