Just about every woman I see with Endometriosis has been told at one time or another that she has an "irritable bowel syndrome" or a "spastic colon" or one of a dozen other terms often used to describe GI symptoms for which there was no obvious diagnosis. Women with endometriosis frequently have gastrointestinal symptoms and, until relatively recently, these symptoms were attributed to either an irritable bowel syndrome, a spastic colon, or, to those of us knowledgeable about endometriosis, to actual intestinal involvement from the disease itself.
It has become increasingly apparent over the past few years that many women with Endometriosis have intestinal involvement. In other words, there are actual implants of Endometriosis either on or in the bowel wall. The medical literature reports an incidence of intestinal involvement ranging from 3 to 34 percent, the average being about 12%. Based on all the figures, a report in the New England Journal of Medicine estimates that 5% of all women have intestinal Endometriosis.
Pelvic Endometriosis is usually (but not always) limited to pre-menopausal women - those with functioning ovaries. Intestinal Endometriosis is different. It is not rare in post-menopausal women. In fact, when a post-menopausal woman develops Endometriosis, it almost always presents with intestinal involvement. Because 70% of intestinal Endometriosis involves the sigmoid colon or rectum, these women are initially believed to have colon or rectal cancer.
The other intestinal sites ( in decreasing order of frequency ) are: appendix, cecum ( the initial portion of the colon), ileum ( the last portion of the small intestine), and lastly, the transverse colon.
Women with intestinal Endometriosis very often have symptoms but, in most cases, the correct diagnosis is not made. In order to diagnose intestinal Endometriosis, it is necessary to ask the right questions. When the proper questions are asked, the diagnosis is easy. The diagnosis is usually made by history, because x-rays of the intestines do not show it and other studies such as colonoscopy do not show it either. Laparoscopy may or may not demonstrate implants on the bowel wall but you have to know where to look for them. Endometriosis implants in the bowel wall may not be detectable except at the time of open abdominal surgery.
Diagnosing intestinal Endometriosis is relatively easy. A woman with intestinal Endometriosis will tell me that she has significant GI symptoms that vary with her menstrual cycle. The symptoms may be present only at the time of the menstrual period or they may be present all month long and worsen at the time of the period. The most common symptoms include loss of appetite, nausea (but vomiting is rare), diarrhea, increased gas, significant bloating, crampy abdominal pain, painful bowel movements, and sharp stabbing rectal pain. Many women also complain of constipation that seems to vary with the menstrual cycle. Unexplained iron-deficiency anemia may also be a clue to the presence of intestinal Endometriosis. Menstrually associated rectal bleeding is diagnostic of intestinal Endometriosis.
In many instances, it is obvious that the woman has intestinal Endometriosis. Either she has menstrually associated rectal bleeding or she has visible implants of Endometriosis on the intestine (either to the large intestine or the small intestine) at the time of laparoscopy. However, there is a sizable group of women who have all of these symptoms but who do not have rectal bleeding and whose intestinal surfaces appear normal at the time of laparoscopy. I was always willing to attribute the symptoms to either microscopic implants of Endometriosis in the bowel wall or perhaps larger implants that were also presumed to be hidden. Keep in the mind that it is the exception, not the rule, to find a woman who has a large mass of endometriosis in the bowel wall.
Recent studies have now shown that rather than attributing the gastrointestinal symptoms to hidden Endometriosis, there is in fact an associated intestinal abnormality that is seen in women with Endometriosis - abnormalities that are not found in women without this disease.
Interestingly, they also showed that the women with Endometriosis had reactive hypoglycemia during a glucose tolerance test.. The blood sugars dropped to an abnormally low level despite having normal insulin levels. This would indicate that women with Endometriosis may be inordinately sensitive to the actions of insulin such that they end up with lower blood sugar levels for a given amount of insulin. One mechanism that has been proposed is that the nerves that help regulate the function of the intestines overreact to the amount of insulin present..
How this will all play out is uncertain at this time. However, it does clearly indicate that women with Endometriosis have intestinal symptoms which do not appear to be related to actual intestinal involvement from Endometriosis but rather an associated intrinsic abnormality in the intestinal wall. This immediately opens the door to the concept that women who develop Endometriosis have underlying endocrine and metabolic abnormalities that differ significantly from women who do not have Endometriosis leading to the conclusion that Endometriosis is a far more complex disease than simply the implants of endometrium where they do not belong.
Many of the symptoms I have just listed are those of the irritable bowel syndrome so it is easy to see why this label is often put on women. Remember that the irritable bowel syndrome is considered to be largely a psychosomatic disorder with an organic component. However, when a woman tells me that her symptoms vary with her menstrual cycle, it is almost certainly intestinal Endometriosis.