The uterus is comprised of 3 layers – the outer layer is called the serosa, the middle layer is the uterine muscle (myometrium), and the inner layer, which is located in the uterine cavity, is called the endometrium. The endometrium is the layer that is shed during a period. When the cells of the endometrium implant in the pelvic and/or abdominal cavity outside of the uterine muscle, it is called endometriosis. The hormone estrogen is produced by the ovary and stimulates endometriosis.
Endometriosis is an inflammatory state and can cause distortion of the pelvic and/or abdominal anatomy with implants or development of adhesions. Symptoms of continuous or cyclic pelvic pain, painful periods, painful intercourse, and infertility can be experienced. If the bowel or bladder is involved, symptoms of bleeding in the stool or urine, bloating, painful bowel movements or urination and/or altered habits may be present. Endometriosis can implant along the ureter causing urinary obstruction, flank pain and dilated kidney. However, most women with endometriosis do not experience any symptoms.
There are several theories as to why and how endometriosis occurs. One theory suggests that the menstrual blood flows backwards through the fallopian tubes into the pelvic cavity and the cells of the endometrium implant on pelvic structures. A theory to understand why endometriosis can occur outside of the pelvic cavity suggests that the endometrial cells travel through the blood stream or lymphatic channels to get to their location of implantation. Some suggest that there may be a genetic predisposition to endometriosis. A few more theories exist, however, no one definitive cause can be identified.
Endometriosis is staged from 1 through 4 depending on the amount of disease present when visibly inspected. Stage 1 is minimal disease where a few, small implants are identified without adhesions in the pelvis. Stage 2 is mild disease where there are more implants located in the pelvis and on the ovaries without adhesions. Stage 3 is moderate disease where the implants are multiple and deep with small endometriomas (cysts of ovaries containing old blood from endometriosis) and pelvic adhesions. Stage 4 is severe disease containing large endometriomas, adhesions, and multiple implants. There is a greater chance for infertility the higher the stage of endometriosis is diagnosed. The amount of pain or symptoms, however, does not correlate with the amount of disease present. For example, a woman with stage 4, severe endometriosis may have no symptoms, but a woman with stage 1, minimal disease may be experiencing severe pain or dysfunction. Therefore, it may be difficult to diagnose the cause of pelvic pain as endometriosis and further work-up may be needed to rule out other causes of pelvic pain depending on the symptoms experienced. Please see link for Chronic Pelvic Pain.
How is Endometriosis diagnosed?
On physical exam, the physician will perform a bimanual exam of the pelvis. The uterus is palpated to check for mobility and tenderness. The tubes and ovaries on both sides are assessed to check if they are enlarged, tender and mobile. A finger in the rectum may be inserted during a pelvic exam to assess behind the uterus where endometriosis can also deposit causing nodules with or without tenderness. Women can still have endometriosis even if the pelvic exam is completely normal. If the pelvic exam is inconclusive, a transvaginal ultrasound may be performed to check if there are any endometriomas (ovarian cysts with endometriosis), otherwise, an ultrasound may not be helpful in visualizing endometrial implants and adhesions.
The most definitive method for diagnosis is laparoscopy. This provides the surgeon direct visualization of the amount of implants, adhesions and size of endometriomas if present. Endometrial implants have many different colors and shapes. Implants can be clear vesicles and/or red, purple, dark brown or black spots or nodules. There can be areas where a “window” is created in the lining of the pelvis (peritoneum). Adhesions can be thin and filmy or thick causing organs to stick together. Endometriomas are cysts identified within the ovary and contain dark blown fluid, commonly called a “chocolate cyst”. The appendix is also inspected because endometriosis can implant there, but also to make sure that it appears normal to rule out as a cause of pain. When no disease is found on laparoscopy, endometriosis may be ruled out as a factor for infertility and pain, however, implants that are too small for the human eye to detect can be present and the woman is treated based on her symptoms.
How is Endometriosis treated?
Therapy for endometriosis varies greatly based on symptoms, extent of disease, age and fertility wishes. The least invasive therapy is to do nothing. If minimal disease is found incidentally during surgery and no or mild symptoms are experienced, then no treatment is reasonable. Also, if a woman is close to menopause, then no treatment is accepted knowing that the endometriosis will not continue to grow due to lack of ovarian hormone stimulation.
Medical therapy may be advised to young women with minimal disease to prevent further growth of endometriosis or to woman with symptoms who do not desire pregnancy at the time. Oral contraceptive pills (OCPs) are commonly prescribed to control ovarian hormone production and the stimulation of endometriosis. If mild pain is also experienced, nonsteroidal anti-inflammatory drugs (NSAIDS, i.e. Ibuprofen) can be used alone or in combination with OCPs. OCPs have minimal side effects and are a good initial approach, as well as NSAIDs, in treating pain caused by endometriosis. Another medication called Letrozole can also be prescribed to help with symptoms of pain. This medication, however, has to be prescribed with OCPs to suppress the ovary from producing too many follicles and may cause bone loss with prolonged use. Therefore, if OCPs with or without NSAIDS do not seem to help, Letrozole can be added to help provide relief. If there is no surgical confirmation of endometriosis and OCPs and NSAIDs are not effective, a trial of Lupron may be recommended to suppress ovarian function if endometriosis is highly suspected as a cause of pelvic pain. After surgical confirmation, Lupron can be given from three to six months. If given longer, low doses of estrogen or progesterone are prescribed to help with side effects, such as hot flashes, insomnia, and bone loss. Other medications that can be used are Progestins and Danazol. Progestins are good for those patients who cannot take OCPs with estrogen, but can cause irregular bleeding, weight gain and worsen depression. Danazol has progestin type effects and is effective however women may experience progestin type side effects as well as an increase in facial hair, acne and deepening of the voice.
Surgery is recommended if medical therapy fails, the disease is severe and/or for infertility treatment. We perform laparoscopy to treat endometriosis. Please see the link for Laparoscopy for a description of this procedure. When a woman desires to preserve her uterus and/or ovaries, any visible lesions of endometriosis are excised or ablated, endometriomas (ovarian cysts containing endometriosis) and scar tissue are removed, and anatomy restored to as normal as safely possible without causing injury to vital tissue or significant blood loss. Some patients have undergone previous surgeries for endometriosis and may require another procedure to help with pain. Another option added to the surgery may be a presacral neurectomy. A presacral neurectomy resects nerves that innervate the pelvis and may alleviate midline pelvic pain. If a woman has completed childbearing or does not desire to retain her uterus, deifinitive surgery would be to undergo a hysterectomy. Please see linkHysterectomy for a description of this procedure. Retaining or removing the ovaries is an individual decision that is discussed with your surgeon.