Endometriosis is a common chronic condition in reproductive-aged women. It is simply defined as the presence of endometrial tissue outside of the uterus. Endometriosis can be found anywhere in the body, but is most commonly seen in the ovaries and lower pelvis.
There are several theories as to the cause of endometriosis, but none has been established with certainty. The three principal theories include 1) retrograde menstruation through the fallopian tubes leading to abnormal implantation of endometrial tissue in the pelvis, 2) spread of endometrial tissue in the blood vessels and lymphatics, 3) coelomic metaplasia or the ability of cells in the pelvic cavity to develop into endometrial tissue.
Endometriosis tends to be seen most commonly in women who have a long duration of uninterrupted menstrual cycles. Such women include those who have never been pregnant, those with an early onset of their menstrual cycle, and those with menopause at a late age. Accordingly, endometriosis is seen less frequently in women who have interruptions in their menstrual cycle – those with multiple pregnancies and long periods of breastfeeding. Endometriosis does have a genetic component as well. Women with first-degree family members diagnosed with endometriosis have a 7% likelihood of developing the disease compared to 1% chance without a family history. Endometriosis also tends to be more common in women of a Caucasian ethnicity compared to African-American and Asian. There is a significantly higher prevalence of endometriosis in women with infertility compared to fertile women. However it is not clear whether endometriosis causes infertility. Proposed mechanisms for how endometriosis may affect fertility include 1) physical distortion of pelvic anatomy; 2) increase in pelvic inflammation; 3) altered pelvic immunology; 4) hormonal dysfunction.
Endometriosis may be associated with pelvic pain, painful periods and/or infertility; however it may also be asymptomatic.
The definitive diagnosis of endometriosis requires surgical biopsy or clear laparoscopically visible pelvic lesions; however the presence of an endometrioma (ovarian cyst of endometriosis) on a pelvic sonogram can help in establishing a strong clinical diagnosis.
There are both medical and surgical options for the treatment of endometriosis. Medical treatment options relieve pain associated with endometriosis, but do not eliminate the disease. Essentially they all work by suppressing endometriosis. Additionally, there is no evidence to suggest that medical treatment improves fertility. Medical therapy includes hormonal treatments and anti-inflammatory medications that can be used separately or in combination. The efficacy of these various medical treatment options is comparable. Surgical treatment of endometriosis is recommended to restore normal pelvic anatomy that is often altered by resultant adhesive disease and to ablate or excise as much visible endometriosis as possible. Furthermore, surgery is suggested for the removal of endometriomas, especially once these cysts are greater than 2 cm.