Endometriosis

Possible sites for endometriosis.Source: National Institutes of Health.

Endometriosis, a common health problem in women, occurs when tissue that looks and acts like the lining of the uterus grows outside of the uterus, in other areas of the pelvis.^[1] These areas are often refered to as implants, lesions, or nodules. Endometriosis can cause pelvic pain and infertility. The condition is named for the endometrium, or tissue that lines the uterus.

Types

Endometriosis can be divided into three categories according to the location and type of lesions: peritoneal endometriosis, ovarian endometrial cysts and deep nodular endometriosis.

Peritoneal endometriosis

These lesions, which occur on the peritoneum, the membrane which lines the abdominal cavity and covers many of the organs, often bleed at the time of menstruation. The lesions tend to cycle through recurrent bleeding, followed by scarring and healing. They vary in color from red to black to white.

Ovarian endometrial cysts

These lesions, often referred to as chocolate cysts or endometriomas, occur when the outermost lining of the ovary encloses the misplaced endometrial lining. These cysts can become large (>3 cm) and can be multilocular (have many parts or cavities).

Deep nodular endometriosis

In this type of endometriosis, the endometrial tissue implants itself deep in the pelvis, especially on fibrous structures like the pelvic ligaments. Nodules are formed by smooth muscle and fibrous tissue that enclose the endometrial tissue. Because the tissue is enclosed, bleeding is not usually an issue with this type of disease.

Staging

Another way to classify endometriosis is by a clinical staging system, updated in 1996 by the American Fertility Society. ^[2] This system assigns points based on the size and depth of the implants and the amount of adhesions (internal scarring) present. The categories are: Stage I (minimal), Stage II (mild disease), Stage III (moderate disease), and stage IV (severe disease).

Signs and Symptoms

Symptoms of endometriosis include:

• Pain with menstrual periods that gets worse over time
• Chronic pain in the lower back and pelvis
• Pain during or after sex
• Intestinal pain
• Painful bowel movements or painful urination during menstrual periods
• Infertility (not being able to get pregnant)

Women with endometriosis may also have gastrointestinal problems such as diarrhea, constipation, or bloating, especially during the menstrual cycle.

The two most common symptoms of endometriosis are pain and infertility.

Usually the pain is in the abdomen, lower back, and pelvis. The amount of pain does not depend on how much endometriosis is present. Some women have no pain, even though their disease affects large areas. Other women with endometriosis have severe pain even though they have only a few small growths.

Many women with endometriosis are infertile.

Causes

Every month, hormones made by the ovaries cause the lining of a woman's uterus to build up with tissue and blood vessels. If a woman does not get pregnant, the uterus sheds this tissue and blood. This blood comes out of the uterus through the vagina as menstrual flow.

The lesions of endometriosis are made of similar cells to those found normally in the uterine lining, but they grow in the wrong place. Instead of growing inside the uterus, they can grow on the ovaries, fallopian tubes, intestines or bladder.

Both inside and outside the uterus, endometrial tissue responds to hormones by building up extra tissue and blood. Lesions tend to get bigger as they fill with blood and can eventually rupture from the increased pressure. That causes blood and inflammatory substances to be released into the abdomen. Tissue and blood that is released by the implants can cause inflammation, scar tissue, and pain, which can sometimes be severe. As the misplaced tissue grows, it can cover or grow into the ovaries and block the fallopian tubes. This can make it hard for women with endometriosis to get pregnant. The implants can also cause problems in the intestines and bladder.

No one knows for sure what causes this disease, but scientists have a number of hypotheses.

• Genetic factors may play a role in the development of endometriosis, as many women who have the condition also have close relatives with endometriosis.^[3]
• Another hypothesis is that during a woman's monthly periods, some endometrial tissue backs up into the abdomen through the fallopian tubes. This transplanted tissue then grows outside the uterus. This process is called retrograde menstruation.^[4]
• A faulty immune system may play a part in endometriosis. In women with the disease, the immune system may fail to find and destroy endometrial tissue growing outside of the uterus.^[5]
• Finally, some scientists believe that the tissues that line the abdomen and pelvis can somehow transform themselves into another type of endometrial tissue.

Diagnosis

The two most common imaging tests to diagnose endometriosis are ultrasound and magnetic resonance imaging (MRI).

However, because many lesions are small (3-5 mm) and may not be seen on radiologic studies, the best method to diagnose endometriosis is to undergo laparoscopy.

Laparoscopy is performed under general anesthesia. First, one or more small cuts are made in the abdomen. A tiny camera with a light is placed inside the abdomen to see if there is endometriosis. Sometimes doctors can diagnose endometriosis just by seeing the growths. Other times, they need to take a small sample of tissue, or a biopsy, and study it under a microscope to confirm the diagnosis.

Treatment

Treatment for endometriosis depends on the patient's symptoms, age and plans for getting pregnant.

Pregnancy itself helps to stop the growth of endometriosis since during the nine months of pregnancy, and often during breastfeeding a woman does not menstruate. Because of hormone changes in pregnancy, the endometriosis does not have a trigger to bleed and the implants often become dormant.

The types of treatment for endometriosis include:

• Pain medication to relieve symptoms
• Hormone therapy to control the growth of endometriosis
• Surgery to remove growths or control the size of very large endometriosis and to relieve pain. In many cases, surgery increases a woman's ability to get pregnant.

Medication

For some women with mild symptoms, doctors may suggest taking over-the-counter medicines for pain. These include ibuprofen (Advil, Motrin) or naproxen (Aleve). When these medicines don't help, doctors may advise using stronger pain relievers available by prescription. However, usually birth control pills are tried before narcotics are prescribed.

When pain medicine is not enough, doctors often recommend hormone medicines to treat endometriosis. Only women who don't want to become pregnant can use these drugs. Hormone treatment is best for women with smaller growths who don't have severe pain.

The following hormones are used to treat endometriosis.

• Birth control pills block the effects of natural hormones on endometrial growths. They prevent the monthly build-up and breakdown of endometriosis lesions. This can make endometriosis less painful. Birth control pills also can make a woman's periods lighter and less uncomfortable. Most birth control pills contain two hormones, estrogen and progestin. This type of birth control pill is called a "combination pill." Once a woman stops taking the pills, the ability to get pregnant returns, but so may the symptoms of endometriosis.
• Progestins or progesterone medicines work much like birth control pills and can be taken by women who cannot take estrogen. When a woman stops taking progestins, she can get pregnant again, but her symptoms may also return.
• Gonadotropin releasing hormone agonists (GnRH agonists) slow the growth of endometriosis and relieve symptoms. They work by greatly reducing the amount of estrogen in a woman's body, which stops the monthly cycle. Leuprolide (Lupron) is a GnRH agonist often used to treat endometriosis. GnRH agonists should not be used alone for more than six months, as they can lead to osteoporosis. If a woman takes another medication along with GnRH agonists, she can use them for a longer time. As with the birth control pills and progestins, when leuprolide is discontinued, symptoms of endometriosis often return.
• Danazol is a weak male hormone. Today, doctors rarely recommend this hormone for endometriosis because of its side effects.

Surgery

Surgery is usually the best choice for women with endometriosis who have many growths, a great deal of pain, or fertility problems.

• Laparoscopy can be used to diagnose and treat endometriosis. During this surgery, doctors surgically remove growths and scar tissue or destroy them with intense heat. The goal is to treat the endometriosis without harming the healthy tissue around it. Women recover from laparoscopy much faster than from major abdominal surgery.

• Hysterectomy should only be considered by women who do not want to become pregnant in the future. During this surgery, the doctor removes the uterus. The ovaries and fallopian tubes may be removed at the same time if they have been damaged by the endometriosis.

Prevention

Being on the birth control pill may decrease the growth of endometriosis.

Chances of Developing Endometriosis

Endometriosis is one of the most common gynecological diseases, affecting more than 5.5 million women in North America. An estimated 10% of women of reproductive age have endometriosis.^[6] It is one of the most common health problems for women.

In general, women with endometriosis have regular monthly periods and are an average of 25 to 29 years old at the time of diagnosis.^[7] Many women have symptoms for two to five years before finding out they have the disease. After menopause (when a woman stops having her period), women rarely have symptoms from endometriosis.

Risk factors

A woman is more likely to develop endometriosis if she:

• began menarche (date of first menses) at an early age,
• has heavy menstrual periods,
• has periods that last more than seven days,
• has a short monthly cycle (27 days or less), or
• has a close relative (mother, aunt, sister) with endometriosis.

Clinical Trials

Endometriosis.org: Clinical trials in endometriosis

ClinicalTrials.gov: clinical trials sponsored by the American government.

Research

There are several intriguing areas of research in the field of endometriosis.

• There may be a link between endometriosis and breast cancer, although it may be that a third factor causes both, rather than one causing the other.^[8]
• A number of possible immunological and inflammatory factors have been identified that may be involved in the development of endometriosis.^[9]
• Methods of treating ovarian endometriomata (excision of the cyst capsule or or drainage and cautery of the cyst wall) were compared for recurrence of symptoms and future fertility. ^[10] Excisional surgery was judged to be more effective in certain circumstances.
• There may be a relationship between exposure to toxic chemicals, such as dioxins and PCBs, and the development of endometriosis.^[11]

Notable Experts

Endometriosis Zone: Physician Advisory Board

Camran Nezhat, MD

Robert N. Taylor, MD, PhD; Emory University, Atlanta, Georgia, U.S.

C.Y. Liu, MD; Chattanooga, Tennessee, U.S.

Tommaso Falcone, MD; Cleveland Clinic

Dan Lebovic, MD, MA; University of Michigan, Ann Arbor, Michigan, U.S.

Simone Ferrero, University of Genoa, Genoa, Italy.

Serdar E. Bulun, MD, Northwestern University, Feinberg School of Medicine, Division of Reproductive Biology Research

References

1. ↑ Bulun SE. (2009) Endometriosis. Mechanisms of Disease Review Article. N Engl J Med 360:268-79. Extract | Full Text
2. ↑ Revised American Fertility Society classification of endometriosis. Fertil Steril. 1985;43:351-2.
3. ↑ Stefansson H, Geirsson RT, Steinthorsdottir V et al. Genetic factors contribute to the risk of developing endometriosis. Hum Reprod. 2002 Mar;17(3):555-9. Abstract | Full Text
4. ↑ D'Hooghe TM, Debrock S. Endometriosis, retrograde menstruation and peritoneal inflammation in women and in baboons. Hum Reprod Update. 2002 Jan-Feb;8(1):84-8. Abstract | PDF
5. ↑ Kyama CM, Debrock S, Mwenda JM, D'Hooghe TM. Potential involvement of the immune system in the development of endometriosis. Reprod Biol Endocrinol. 2003 Dec 2;1:123. Abstract | Full Text
6. ↑ Jackson B, Telner DE. Managing the misplaced: approach to endometriosis. Can Fam Physician. 2006 Nov;52(11):1420-4. Abstract | Full Text
7. ↑ Wellbery C. Diagnosis and treatment of endometriosis. Am Fam Physician. 1999 Oct 15;60(6):1753-62, 1767-8. Erratum in: Am Fam Physician 2000 May 1;61(9):2614. Abstract | Full Text
8. ↑ Bertelsen L, Mellemkjaer L, Frederiksen K, et al. Risk for breast cancer among women with endometriosis. Int J Cancer. 2007 Mar 15;120(6):1372-5. Abstract
9. ↑ Kyama CM, Mihalyi A, Simsa P, et al. Non-steroidal targets in the diagnosis and treatment of endometriosis. Curr Med Chem. 2008;15(10):1006-17. Abstract
10. ↑ Hart RJ, Hickey M, Maouris P, Buckett W. Excisional surgery versus ablative surgery for ovarian endometriomata. Corchrane Database Syst Rev. 2008 Apr 16;(2):CD004992. Abstract
11. ↑ Rier SE. Environmental immune disruption: a comorbidity factor for reproduction? Fertil Steril. 2008 Feb;89(2 Suppl):e103-8. Abstract

Additional Reading

Stephen J. McPhee, Maxine A. Papadakis, Lawrence M. Tierney. (2008) Current Medical Diagnosis and Treatment: 2008. Edition: 47. McGraw-Hill Professional. ISBN 0071494308, ISBN 9780071494304.| Full Text Section on Endometriosis (on Pages 645-646)

ADAM. "Endometriosis In-Depth." 03 April 2007. HowStuffWorks.com. http://healthguide.howstuffworks.com/endometriosis-in-depth.htm 08 March 2009.

External Links

The American College of Obstetricians and Gynecologists: Endometriosis

The National Women’s Health Information Center Endometriosis FAQs

American Society of Reproductive Medicine (ASRM)

The Endometriosis Research Center

Gallery of Images Related to Endometriosis