What Is Endometriosis, Exactly?
Endometriosis is a condition in which tissue similar to the lining of the uterus, the endometrium, grows in places outside the uterus. It occurs in around one in ten women of reproductive age and is diagnosed most often in women in their thirties and forties, although it can affect younger women too.
The tissue most commonly grows on the peritoneum, the membrane that lines the abdominal cavity, as well as on the ovaries and fallopian tubes, and occasionally on the outer surface of the bladder, bowel or uterus itself.
What Is Deep Infiltrating Endometriosis?
Most endometriosis sits on the surface of the tissue it affects. Deep infiltrating endometriosis behaves differently. It grows more than five millimetres beneath the surface, forming firm nodules that can invade the ligaments behind the uterus or the walls of nearby organs such as the bowel and bladder. It tends to cause more severe pain and is the form most likely to need specialised surgery.
Deep endometriosis is usually described by where it is found:
- Bowel endometriosis most often affects the rectum and sigmoid colon, the last part of the large bowel. It can cause pain with bowel movements or changes in bowel habit around your period.
- Bladder endometriosis may cause pain or urgency when passing urine, sometimes with blood in the urine during menstruation.
- Ureteric endometriosis affects the ureters, the tubes that drain urine from the kidneys. It may cause no symptoms at all, which is why the kidneys are checked as part of a mapping scan.
- Diaphragmatic endometriosis is found above the pelvis, on the muscle beneath the lungs, and typically causes pain in the right shoulder tip or chest around the time of a period.
Because deep disease can involve more than one organ, endometriosis mapping is used to chart it in detail before treatment. This allows surgery to be planned with a colorectal surgeon or urologist where needed, as explained on the endometriosis surgery page.
Why Does It Cause Pain?
Endometrial tissue responds to the same hormone, oestrogen, that governs your monthly cycle. Wherever it has implanted, it can thicken and bleed in step with your period, even though it has no way to leave the body the way the uterine lining does. The surrounding tissue becomes irritated and inflamed, and repeated bleeding can lead to scar tissue, known as adhesions, which sometimes cause organs to stick together.
This cycle of inflammation and scarring is what produces the chronic pelvic pain that many patients describe, particularly in the days before and during a period.
Who Gets Endometriosis?
There is no single cause that explains why one woman develops endometriosis, and another does not, though hormonal and immune factors both appear to play a role. A family history of endometriosis can raise the likelihood of it, and it is worth mentioning to Dr Groenewald if a mother or sister has been diagnosed.
The condition is also more often picked up in women being investigated for difficulty falling pregnant, since endometriosis and fertility are closely linked. This does not mean every woman with endometriosis will struggle to conceive, but it is one of the reasons an earlier diagnosis is worth pursuing rather than waiting.
