Endometriosis is one of the most enigmatic diseases1 which is characterized by debilitating pain for many of those who have been diagnosed with it2. While endometriosis derives its name from the endometrium (tissue that lines the uterus), it is defined as the presence of endometrial-like deposits (lesions or implants) outside of the uterus. Functionally, these deposits act similarly to the endometrium. Cellularly and molecularly however, these deposits are different to the tissue that is found in the uterus and induce an inflammatory response through which scarring, adhesions and other physiological changes can occur. Due to these changes which occur in many cases, endometriosis has been associated with chronic pelvic pain, painful menstruation, and painful intercourse. Endometriosis is also implicated in up to 50% of women who have infertility.
In 1927, Dr. John Sampson posited that endometriosis was due to retrograde menstruation. Meaning, instead of exiting the body, menstrual tissue would flow backwards into the fallopian tube and enter the pelvic cavity. These cells, if viable would implant in and around the pelvis, forming lesions which could then grow. As endometriosis is typified by painful menstruation and chronic pelvic pain, this theory of its pathogenesis was accepted for many years. However, as the condition has been studied many years since the initial theory, other theories have been proposed. One reason for this is that Sampson’s theory does not provide enough evidence to explain the fact that retrograde menstruation is common among women; however not all women have endometriosis3. Another reason why this theory does not adequately account for the development of endometriosis, is that endometriosis has been found outside of the pelvis and more specifically, has been found in and on other non-reproductive system organs.
Understandably for many, the initial introduction endometriosis has been based on its characterization as a benign gynaecological condition4. This is due to the most common symptom of painful menstruation as well with it being a risk factor of infertility in women5. Thus, there is more awareness of endometriosis affecting the organs and structures of the female reproductive system including the ovaries, uterus and fallopian tubes2. Typically, women experiencing complaints of painful periods or difficulty falling pregnant will eventually seek the services of healthcare providers and in most cases be seen by a gynaecologist. This is important as these complaints are valid and there is an array of psychosocial negative outcomes associated with chronic pelvic pain and dealing with subfertility/infertility.
However, endometriosis is an inflammatory systemic condition and deposits are found on or in other organs outside of the reproductive system. As early as 1989, scientific literature has outlined the presence of endometriosis in and on organs in the digestive, urinary, respiratory, nervous, integumentary (skin), and cardiovascular systems6. Extra pelvic endometriosis is the overarching term which describes endometriosis found in and on organs outside of the pelvis and reproductive system. When endometriosis lesions are found in the pelvis but not on organs associated with reproduction, this is known as extragenital endometriosis7.
The most common extra pelvic location of endometriosis is the thorax (or within the chest). Thoracic endometriosis syndrome (TES) typically can occur with pelvic endometriosis and in fact, this is the case with is most patients. Symptoms and clinical manifestations of TES vary but persons typically complain of chest pains during menstruation as well as outside of their cycle. One very serious outcome of TES is catamenial (menstruation) pneumothorax9- or lung collapse. For persons with TES who experience pneumothorax, air is thought to enter the pleural space due to the endometriosis on the membrane which surrounds the lungs and diaphragm, disrupting regular function and requiring immediate medical attention.
The digestive system- specifically, the gastrointestinal tract, has been identified as the most common location of endometriosis outside of the reproductive system with the bowels (large intestines) being the most common site of extragenital pelvic endometriosis. Bowel endometriosis can present with endometrial lesions located on the bowel (superficial) or penetrate the walls of the colon (deep infiltrating endometriosis-DIE). Symptoms of bowel endometriosis can resemble symptoms of many other digestive system ailments, including irritable bowel syndrome. These include pain when defaecating, constipation and diarrhoea. Some persons may also experience pain during intercourse. Typically, the pain with defecation with bowel endometriosis tends to be worse during menstruation. Another site of extragenital pelvic endometriosis is the urinary system. Bladder endometriosis, where endometriosis can also be present on or within the walls of the bladder is the most frequently reported location of urinary tract endometriosis (UTE). Symptoms of bladder endometriosis can include frequent and painful urination. Additionally, while considered rare and generally asymptomatic, ureteral endometriosis can be a precursor for kidney disease and renal failure as the ureters are the structures through which urine flows from the kidneys to the bladder. Blockage of the ureters can lead to enlarge kidneys because of the impaired function and lack of drainage and then potentially kidney failure8.
These examples of extragenital and extra pelvic endometriosis underscore the need for a greater awareness and understandingendometriosis is a systemic inflammatory condition with potentially far-reaching consequences. While the most common sites of disease are those of the reproductive system, it must be understood that these are not the only sites endometriosis can be found and not only cause pain, but also disrupt the physiology and function of vital organs. What
ongoing research of endometriosis has shown is that because it can affect other organs, the multidisciplinary approach to treatment and management is a potential best practice, with improved patient outcomes. Medical and health care specialists from various fields can collaborate on a customized approach to the diagnosis, treatment, and long-term management of the patient. We must consider that with almost 200 million women and girls from all backgrounds affected, it may be time to reframe how we think about endometriosis- it is more than a reproductive health issue.
