Endometriosis is generally thought of as a reproductive system disease, probably owing to the fact that one common symptom is painful menstrual periods, and that it can cause infertility. The truth is that this is not solely a reproductive disease at all. It can affect the reproductive organs, but it also commonly affects other organ systems such as the intestines and bladder. More rarely, it can also affect areas outside of the pelvis altogether such as the sciatic nerve, the diaphragm, and lungs, and even the calf muscle. In addition to pelvic-specific symptoms such as pelvic pain, bowel and bladder dysfunction, and painful intercourse, many women with endometriosis report systemic symptoms such as fatigue and general malaise, and women with endometriosis have a higher incidence of many diseases such as autoimmune diseases, allergies, inflammatory bowel disease, and even a slightly increased risk of ovarian cancer. The links between endometriosis and these other diseases are not well understood.
Many people may be familiar with the fact that endometriosis is caused by misplaced tissue in the pelvis that forms lesions, cysts, and nodules. However, given its reputation as a reproductive disease, most people expect that it usually grows on the reproductive organs—the ovaries and the uterus. This has been found not to be the case, and even though the work demonstrating that the most common locations for lesions are not the ovaries or uterus was published in the medical literature 24 years ago, the misconception still persists to this day, even among physicians.
Dr. David Redwine, a pioneering laparoscopic surgeon, published a study of the distribution of endometriosis in the pelvis by age group and fertility in 1989. This study described the locations of endometriosis in the pelvis in 132 consecutive patients undergoing laparoscopic surgery. The most common area where endometriosis was found, in all age groups, was the cul-de-sac, which is the area behind the uterus, between the uterus and the rectum. The next most common areas were the ligaments of the pelvis (the broad ligament, and uterosacral ligament, with the right side being involved more often than the left). After the ligaments, the bladder was most commonly involved, and then the left ovary. Then the fundus of the uterus (the top end, opposite the cervix), the sigmoid colon, the right ovary, then finally the Fallopian tubes, the round ligaments, and the abdominal wall.
This study also suggested that, contrary to the popularly held belief that endometriosis spreads to more pelvic areas over time, it does not in fact spread. Lesions can grow and deepen over time, leading to more significant symptoms and potentially organ damage. However, in this study, older women as a group did not have more areas of the pelvis involved by endometriosis than younger women, which is what would be expected if endometriosis did spread in location over time.
The most interesting thing about this study is perhaps not the results themselves, but the fact that 24 years later, the results and their implications for treatment have not been incorporated into practice by many physicians treating this disease. First of all, endometriosis as a multisystem disease requires surgical expertise that often goes beyond what most gynecologists are trained to deal with. And yet many gynecologists who do not have the surgical skills to remove endometriotic tissue from sensitive areas like the sigmoid colon still continue to treat these patients, even those with complex disease, rather than refer them to specialists.
More importantly though, the dismissal of endometriosis as simply a reproductive system disease seems to lead to a lack of understanding of the debilitating symptoms it can cause. Studies on the quality of life for women with endometriosis have shown that women still continue to suffer from frequent symptoms including chronic pain, that impair their quality of life, even after treatment for their endometriosis. The severe pain experienced by many patients with this disease is dismissed in a way that pain from other diseases doesn’t get dismissed. Nancy Petersen, a recognized patient advocate, and Founding Director of the first Endometriosis Excision Treatment Program in the U.S., has compared the pain of endometriosis to the pain of acute appendicitis. During acute episodes of endometriotic pain, patients are often offered Tylenol or naproxen by physicians—would physicians even consider offering those medications to a patient with acute appendicitis? How long will the undertreatment of endometriosis pain persist by many physicians because of the misguided perception that it’s just a “women’s problem” and therefore can’t be that serious or painful?