Endometriosis is a condition whereby tissue similar to the inside lining of the uterus is found outside the uterus. Worldwide it is estimated this condition affects 10% of women, from puberty to menopause.
Endometriosis is the most common cause of pelvic pain and it is responsible for about 25% of cases of infertility. The pain for some women is so debilitating that it impacts heavily on their lives. This pain usually occurs during the menstrual period but in severe cases may be present throughout the month. Another common symptom is deep pelvic pain with or following intercourse. Some women with significant endometriosis have no symptoms until they try to achieve a pregnancy.
Endometriosis lesions are usually found in the inner linings of the pelvis. Other sites include the uterus, fallopian tubes, ovaries, appendix, bowels and diaphragm. In the ovaries, endometriosis can form cysts that can grow to a large size. These are called endometriomas or “chocolate cysts”.
A thorough gynaecological examination can often detect lesions and replicate the pain of endometriosis. Tests such as ultrasound, CT scans and MRI may also be useful in detecting endometriosis especially where chocolate cysts are present. But mostly, these tests do not show any lesions and the only definitive way to make the diagnosis of endometriosis is to perform laparoscopic (keyhole) surgery.
There are multiple medical treatments available for the control of the symptoms of endometriosis. As the growth of endometriotic lesions is driven by oestrogen levels, most treatments rely on hormonal manipulation.
For most women, starting a low dose oral contraceptive pill (OCP) is enough to reduce the symptoms to manageable levels. Some women do not tolerate the OCP and may require a progesterone loaded intrauterine device (IUD) such as the Mirena. For some women these treatments eventually fail and surgical excision of the endometriosis is needed. Other therapies for recurrent disease are sometimes used. A class of drugs called gonadotrophin releasing hormone agonists are used and come as implants (Zoladex) or a nasal spray (Synarel). These can only be used for a short period of time as they bring on symptoms of the menopause and can have permanent long term effects if used for more than 6 months (e.g. osteoporosis). These may also be used to decrease the size of lesions prior to surgical excision.
Laparoscopic (keyhole) surgery is the only definitive way to confirm a diagnosis of endometriosis. Endometriotic lesions can have many different appearances and require a skilled and experienced laparoscopic surgeon to detect all lesions. It is believed you only get one really good chance of curing endometriosis and that is to excise all visible lesions at the first laparoscopic procedure. Recurrence of disease will occur in about 4% of women and these women often require multiple laparoscopies until the condition settles after the menopause.
Endometriosis has been linked with infertility. The mechanism by which endometriosis causes infertility is not well understood. It is thought that endometriosis releases certain chemicals which are toxic to eggs and embryos. In general, the more endometriosis there is, the more likely the woman will be infertile. This is not always true as some women with minimal disease may also be infertile and are then able to achieve a pregnancy naturally once the endometriosis is excised.