The Diagnosis and Treatment of Endometriosis



Endometriosis refers to the condition in which cells from the endometrium, the tissue that normally forms the lining of the uterine cavity, become embedded in areas of the body outside of the uterus. When present, small implants of endometriosis, measuring several millimeters in diameter, are most commonly found in the lower abdomen of women, either on the inside lining of the pelvis or on the surface of the ovary, uterus or intestine.

In more advanced cases of pelvic endometriosis, scar tissue, also known as adhesions, may develop between the uterus, ovaries, fallopian tubes and intestines, either bridging the gap between these structures or causing them to be tightly stuck to each other. Occasionally, invasion of endometriosis into the substance of the ovary results in a localized accumulation of blood within a cyst cavity known as an endometrioma. Over time, the blood becomes a dark brown color, resulting in the alternative designation as a "chocolate cyst." Rarely, scar tissue resulting from endometriosis can cause an obstruction of the intestine or the ureter leading from the kidney to the bladder. The combined amount of active endometriosis and adhesion formation can be classified into categories of minimal, mild, moderate or severe disease using a scoring system established by the American Society for Reproductive Medicine. This offers a standardized scheme for comparison among different women with endometriosis.


The most commonly accepted explanation for the development of pelvic endometriosis begins with the flow of endometrial tissue through the fallopian tubes and into the lower abdominal cavity during a woman's menstrual period. There, the cells from the endometrium attach to and grow on the surfaces of the lower abdominal lining and pelvic organs, and sometimes invade more deeply into these structures. Although most women probably experience some flow of menstrual tissue through the fallopian tube during their period each month, we do not completely understand why some women develop endometriosis and others do not. It is thought that individual genetic and immunologic factors may influence the occurrence and progression of endometriosis in each woman. This would explain why some women have a minimal and stable amount of endometriosis for many years while other women may have more extensive and progressive disease that may be more difficult to treat effectively. An increased occurrence of endometriosis has been found in the mothers and sisters of women with endometriosis.

In addition to its typical location within the pelvis, there have been rare cases of endometriosis located in the upper abdominal or chest cavities, the vagina, the nose (resulting in monthly nose bleeds) or within scars from previous abdominal surgery or episiotomy. Endometriosis has even been diagnosed in some men treated with estrogen. There are several theories for how endometriosis might be present in such varied locations. To explain the finding of endometriosis outside of the abdominal cavity, it has been proposed that endometrial tissue may also spread through blood vessels or the lymphatic ducts, or may form in uncharacteristic locations during fetal development.


Because the growth of endometriosis is stimulated by estrogen, it occurs mostly in women of reproductive age and is rarely seen before the onset of menstruation or after the menopause. It is difficult to know how many women actually have endometriosis because women often have no symptoms of its presence and the condition is generally not visible with standard imaging tests such as ultrasound or x-ray. However, cases that are diagnosed occur with equal frequency in women of all races and nationalities. Endometriosis can be found in 30 percent to 50 percent of women undergoing a laparoscopy for infertility but may also be found in women of normal fertility who undergo tubal ligation or other abdominal surgery.



Pain, resulting from a localized inflammatory response triggered by the implants of endometriosis, is generally the most obvious symptom of the disease. Because endometriosis is stimulated by the same hormones that induce a woman's menstrual period, the pain resulting from endometriosis is usually increased for several days before the start of a menstrual period and also during the menstrual period itself. Thus, a history of progressively severe menstrual cramping or pelvic pain in a reproductive-age woman is highly suspicious for the presence of endometriosis.

Unfortunately, the degree of pain does not necessarily correlate with the extent of the disease. A minimal amount of endometriosis, if located over nerve bundles, may cause severe menstrual pain. The presence of an endometrioma can result in more consistent pain on the side of the involved ovary with no effect on menstrual cramping. Traction on the pelvic organs by adhesions may lead to pain with intercourse and/or pain that becomes more constant and persists even after the menstrual period is over. Since endometriosis may rarely implant on the intestines, the bladder, or the ureter, other symptoms can include rectal pain or bleeding, urinary urgency or blood in the urine.

Some women, even with multiple endometriosis implants and extensive scar tissue formation, are remarkably pain-free. In these women, endometriosis may only be found as part of an evaluation for infertility or by the coincidental finding of an endometrioma during an ultrasound, CT scan or MRI of the pelvis that was performed for other reasons.


Because pain is not always present, the only symptom of endometriosis in some women is infertility. Even the presence of only a few small implants of endometriosis appears to reduce a woman's conception rate for reasons that are not completely understood. It is theorized that the increased pelvic inflammation caused by endometriosis may affect the ovulation process, the function of the fallopian tube and/or the function of the sperm that have swum into the tube, preventing fertilization of the egg.

The presence of adhesions that distort the normal anatomic relationships between the uterus, fallopian tubes and ovaries in more severe cases of endometriosis results in a more obvious and treatable cause of infertility. For example, scar tissue may cover the ovary or cause it to adhere to the wall of the pelvis, preventing the egg from escaping from the ovary at the time of ovulation. Alternatively, scar tissue may fix the fallopian tube in a position remote from the ovary, making it difficult for the released egg to enter the tube and be fertilized.


The presence of endometriosis is suggested by a history of increasing pelvic pain or by the inability to achieve pregnancy over a reasonable period of time. Physical examination is often normal but may show nodularity within the vagina or lower pelvis from scar tissue formation, ovarian cysts, or, in the case of severe disease, a uterus which is fixed in position by adhesions.

Unfortunately, endometriosis is not visible on x-ray and cannot be seen with ultrasound unless a chocolate cyst is present within the ovary. For this reason, the diagnosis of endometriosis must be confirmed by laparoscopy, an outpatient surgical procedure, performed under general anesthesia, during which a telescope-like instrument is inserted through a small incision in the belly button to visualize the implants of endometriosis and any adhesions that may be present within the pelvis. In most cases, removal of endometriosis implants, endometriomas and scar tissue can also be performed during the same procedure. More advanced cases, which may not be technically feasible or safe to correct with laparoscopy, may require more extensive surgery through a larger incision. Other tests that may be helpful in selected cases include CT or MRI imaging of the pelvis, intravenous pyelography (IVP) and cystoscopy to examine the ureter and bladder, and barium enema or colonoscopy to evaluate the intestinal tract.

General Treatment Considerations


The painful symptoms of endometriosis are generally manageable with medical therapy or surgical removal of the endometriosis. Medical treatment will generally shrink endometriosis implants while in use and for a variable period of time after it is discontinued. However, medications are not effective in removing any pelvic adhesions that may be present and have limited effectiveness in shrinking ovarian endometriomas. In these settings, surgery is generally the treatment of choice. There is an estimated pain recurrence rate of five percent to 20 percent per year following medical treatment and one percent to 10 percent per year following corrective surgery.


Surgical treatment is preferred for the treatment of endometriosis in the setting of infertility because the available medical treatments for endometriosis will suppress ovulation while they are in use and will not be effective against any scar tissue that may contributing to the infertility. Although women with minimal to mild endometriosis have a lower monthly pregnancy rate than women without the disease, there does not seem to be any clear improvement in pregnancy rates when this degree of endometriosis is treated medically or surgically. The surgical treatment of moderate to severe cases of endometriosis does appear to offer some degree of success, especially with the removal of ovarian endometriomas, the removal of scar tissue and the restoration of normal pelvic anatomy.

Women with infertility due to endometriosis, especially when pain relief is not an objective, may be candidates for in vitro fertilization (IVF). The pregnancy rate that results from IVF in women with endometriosis, regardless of the extent of their disease, appears to be similar to the results of IVF performed for other infertility-related diagnoses.

Medical Therapy

Medical therapy is usually recommended for symptomatic women who are not currently desirous of pregnancy because all of the available medications will prevent ovulation and can cause problems if taken during pregnancy. Since endometriosis appears to be stimulated by estrogen, medical therapy is directed towards reducing the estrogen effect on endometriosis or by reducing the overall production of estrogen by the ovaries. The response of endometriosis to medical treatment may vary among different women.

Oral Contraceptives

Birth control pills are commonly used as initial therapy for women suspected of having endometriosis who wish to defer laparoscopy or to prevent recurrence of the disease after surgical treatment. Women who take birth control pills tend to have lighter menstrual periods with less cramping and may be less likely to reseed new areas of endometriosis within the pelvis. Low-dose birth control pills can be used in a cyclic fashion, with a rest period to allow a menstrual period to occur, or can be given continuously to avoid menstruation for women with persistent pain during their periods. Although there is a theoretic concern that the estrogen component of the birth control pill may potentially stimulate growth of the endometriosis, this effect appears to be balanced by the progestin component of the pill, which tends to inhibit the estrogen effect on endometriosis.


Progestins are synthetic versions of progesterone hormone that oppose the effect of estrogen. For women who cannot take birth control pills, a progestin alone can be tried, either orally in pill form or as an intramuscular injection given every three months (Depo-Provera). The irregular bleeding, weight gain and depression that can result from the use of progestins alone have made the use of this agent less attractive.


Women with more severe cases of endometriosis that do not respond to birth control pills or progestins and who wish to defer surgery can be treated with a class of medication known as gonadotropin releasing hormone agonists. These drugs are a modification of gonadotropin releasing hormone (GnRH), a hormone normally produced by the brain that acts via the pituitary gland to stimulate estrogen production by the ovaries. Instead of stimulating estrogen, however, the modified hormone suppresses estrogen concentrations down to levels seen during the menopause. Both Lupron and Synarel are GnRH agonists that are currently approved by the FDA for the treatment of endometriosis. Lupron is available as a long-acting depot preparation that is given by intramuscular injection by a physician, either monthly or every three months, and also as a daily subcutaneous injection that a woman may self-administer. Synarel is a nasal spray that is also self-administered on a daily basis.

GnRH agonists are generally given for six months and will relieve symptoms in up to 85 percent of women during their use. Although some women may obtain long-lasting relief after the completion of treatment, symptoms will often return within several months. A concern about the eventual development of osteoporosis with long-term estrogen suppression by these medications has generally limited the use of GnRH agonists to short-term treatment intervals. But women with recurrent pain may be maintained on long-term GnRH agonist therapy with regular bone density scans and the addition of other medications to prevent bone loss. The side effects of GnRH agonists generally include hot flashes along with the potential for vaginal dryness and mild depression as a result of the marked decrease in estrogen levels that occur. The side effects of the Synarel nasal spray appear to be less severe than with the use of Lupron injections.

Surgical Therapy

Surgery is usually recommended to relieve endometriosis-related pain in women who do not respond to or cannot tolerate medical treatment, or to improve the fertility potential of women with endometriosis who are actively trying to conceive a pregnancy. Surgery is the only treatment option in the presence of pelvic adhesions or ovarian endometriomas. A surgeon experienced in operative laparoscopy may, in many cases, provide adequate treatment by directly treating endometriosis implants and removing scar tissue during an outpatient procedure. In some cases, however, there may be a need for inpatient surgery through a larger incision to properly repair the damage caused by severe disease. Pregnancy rates following surgery range from 35 to 60 percent, depending on the extent of disease.

Symptomatic patients beyond the stage of childbearing, who do not respond to medical therapy or more conservative surgery, may wish to consider removal of both ovaries to eliminate the source of estrogen production. This is the only true cure for recurrent endometriosis. This decision requires careful thought and consultation and is usually an option of last resort after the failure of other treatment modalities. If the resulting hot flashes after surgery are problematic, estrogen replacement therapy may be carefully started at low doses several months after surgery, with close observation for evidence of recurrence of the endometriosis.

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