The endometrium is the tissue that lines the inside of the uterus. Endometriosis occurs when endometrial tissue moves to other areas of the body.
The endometrium is the tissue that lines the inside of the uterus. Endometriosis occurs when endometrial tissue moves to other areas of the body. These growths are generally not cancerous; they are normal tissue, but outside the normal location.
Most of these tissue growths, also referred to as nodules, lesions or implants, are found in the ovaries and fallopian tubes. However, they can also occur in or on the intestine, bladder, bowel, vagina, rectum, cervix and vulva. Rarely, endometriosis can occur outside the abdomen, in the lung, arm, thigh, skin and even the brain.
The endometrial growths respond to menstrual-cycle hormones in the same way as the uterus lining. Each month the tissue builds up, breaks down and sheds. While blood from the uterine lining can leave the body through the cervix and vagina, bleeding from endometrial implants at all ectopic (out-of-place) sites becomes trapped.
This results in internal bleeding, inflammation (swelling and irritation), and the formation of scar tissue and blood-containing cysts. With each menstruation, these cysts expand and cause pain. Endometriosis may also result in nodules that are associated with pain during intercourse, scarring and/or infertility.
The growths can also rupture and spread to new areas. If they are on or near the bladder, bowels or intestine, they can interfere with these organs’ functions.
The cause of endometriosis is not known: no single theory seems to account for all cases.
During menstruation, pieces of uterine lining or endometrial tissue may get pushed backwards up the fallopian tubes towards the ovaries and abdominal cavity. This tissue then implants itself and develops into endometriosis.
Another theory suggests that endometrial tissue is distributed to other parts of the body by the lymph or blood system.
Endometriosis is often found in abdominal surgical scars, giving rise to the theory that it is somehow transplanted during surgery. However, it has also been found in scars where this seems unlikely.
The symptoms of endometriosis are various, inconsistent and non-specific. It is possible to have some, all, or none of the complaints listed below. Some women show no symptoms, especially in the early stages, while others suffer from discomfort, debilitating pain and/or infertility.
Endometriosis is classified according to where the endometrial tissue is located, whether it is on or buried beneath an organ’s surface, and whether growths are thin or dense. The presence and intensity of symptoms are not related to the extent or size of the tissue growths, but rather to where the implants are and how deeply they have penetrated into normal tissue.
The most common symptom of endometriosis is pain, usually in the lower abdomen, pelvic or lower back area. Pelvic pain may be caused by the collection of menstrual blood in the abdominal cavity, causing inflammation.
Pain may be experienced at various times:
- Before and during menstruation (dysmenorrhoea). Pain can begin a few days before the start of menstruation and is usually at its worst during the heaviest flow.
- During or after sexual intercourse (dyspareunia)
- During urination or bowel movements while menstruating
Other symptoms may include:
- Heavy or irregular periods
- Backache during menstruation. This usually occurs when endometrial tissue implants on the intestine.
- Gastrointestinal upsets such as diarrhoea, cramping, constipation and nausea
- Rectal bleeding or blood in stool
- Blood in urine
- Coughing up blood, particularly during menstruation (rare)
- Shortness of breath or accumulation of air in the chest (rare)
- Leg or hip pain
- Pain in the right lower abdomen, as with appendicitis. This can occur if endometrial tissue implants on the appendix.
- Fatigue, allergies and other immune system-related problems
The course of endometriosis is unpredictable. It is a chronic (long-term) condition and the symptoms usually worsen with time, although the rate of progression varies from woman to woman. Symptoms may remain stable, decrease or increase, with or without treatment. They may also disappear with treatment, but return later. Cycles of remission and recurrence occur in some cases.
Generally, the onset of menopause usually results in the decrease of endometriosis. However, severe endometriosis can be reactivated by hormone-replacement therapy or continued hormone production after menopause.
Endometriosis can be classified as minimal, mild, moderate or severe, based on the AFS/ASRM scoring system:
- Stage one endometriosis is mild, where tissue growth is slight, scattered around the pelvic cavity and easy to treat.
- Stage two is still mild, but is situated more deeply in the tissue.
- Stage three endometriosis is moderate, with larger patches of endometrial tissue that is more widely spread. Cysts may be present.
- Stage four is severe, where tissue growth is large and deep and most of the organs in the pelvic cavity are affected. The uterus and ovaries are often covered in scar tissue and the fallopian tubes may be blocked.
Endometrial tissue attached to an ovary or inside an ovary can form an endometrioma, or ovarian cyst lined by endometrial tissue:
- These cysts are also called chocolate cysts, because of the dark, red-brown blood inside.
- As the endometriosis grows and sheds every month, the fluid inside the cysts accumulates and the cysts grow.
- An endometrioma can rupture or leak, causing sudden, sharp abdominal pain. The material inside the cyst can adhere to surfaces within the abdominal cavity and may cause irreversible damage to the fallopian tubes. They may get infected and cause abscesses.
Other less common complications of endometriosis may include:
- Kidney impairment due to scar tissue build-up, blocking urine flow or bowels
- The growth of endometrial tissue in the lungs, which can cause the collapse of a lung
- Growths in the brain or spinal cord, which can lead to seizures or paralysis
Infertility and pregnancy
Infertility may be associated with endometriosis. Possible reasons include:
- Abnormal hormonal function
- Infrequent intercourse due to pain
- Abnormal ovulation
- Affected sperm transportation
- Anatomical distortion with tubal blockage
- Impaired immunological function
- Ovarian damage following surgical treatment
Women with endometriosis are often advised not to postpone pregnancy, as the more the disease progresses, the more likely it is to cause infertility. This is a highly personal and life-changing decision. The likelihood of genetic links plays a role in this choice, as women could pass on the risk of developing the disease to their offspring.
Pregnancy often causes a remission of endometriosis, as ovulation ceases, causing the growths to shrink. But it is not a definitive cure – some women report relief from pain during pregnancy, while others report no relief at all. In many cases, endometriosis can return after pregnancy.
Risk factors include:
- Genetic inheritance
- Race (more common in white women)
- Abnormal menstrual disorders
- Delayed childbearing
- Outflow obstruction
- Impaired immune function
When to see a doctor
A woman should consult a doctor if she:
- Has pain during intercourse
- Experiences pain during urination or bowel movements
- Sees blood in her urine or stools
- Experiences pain that interferes with daily activities
- Is unable to fall pregnant after trying for 12 months
Women who experience only mild symptoms of endometriosis, or who are approaching menopause, may decide to adopt a “watch and wait” approach. This involves waiting through several menstrual cycles to monitor the symptoms, and then discussing them with their doctor.
It is important to give your doctor a good description of your symptoms, menstrual periods and how long you have had problems. Describe all risk factors, including any family history of endometriosis.
The severity of endometriosis is determined after studying the uterus, fallopian tubes, ovaries, and the entire abdomen and pelvis. The doctor can perform a pelvic examination to feel whether any growths are detectable. It is important to visit the doctor during menstruation, or when the pain is greatest. Although this can be embarrassing, this is when the endometrial implants will be at their largest and easiest to feel.
There are three common types of endometriosis: peritoneal endometriosis, ovarian endometriosis (only on the surface or with cysts), and recto-vaginal endometriosis. Ovarian cysts (endometrioma) are often seen on ultrasound. Diagnosis of recto-vaginal endometriosis may need a combination of rectal examination, ultrasound and/or colonoscopy. Peritoneal endometriosis is best diagnosed with laparoscopy.
Laparoscopy is a surgical procedure done under general anaesthesia. An incision (small cut) is made through the navel and a telescopic instrument, called a laparoscope, is inserted so that the doctor can see the abdominal cavity. One or two more 1cm incisions are made to put instruments through, so that the internal organs can be manipulated and inspected. This procedure helps to determine the location, size, and extent of the growths.
If growths are found, a small tissue sample may be taken for examination at a laboratory. Generally, this is not necessary, as endometriosis can be diagnosed on naked-eye inspection. Photographs may be taken (by a camera on the laparoscope) to allow the doctor to visually compare findings before and after treatment, should another laparoscopy be necessary later on.
The patient may go home a few hours after the procedure (although she may not drive a vehicle for 24 hours after anaesthetic). Because carbon dioxide gas is used to inflate the abdomen so that organs can be safely visualised, there may be some abdominal discomfort and shoulder pain (the gas irritates nerves leading to the shoulders), but this will disappear in 24 to 48 hours.
Although there is no cure for endometriosis, a variety of treatment options exist. Medication can shrink the endometrial growths, or surgery may be necessary to remove the implants. A combination of surgery and medical therapy may be used. A specialist doctor can suggest the most appropriate option. It is important to evaluate:
- Whether the symptoms are serious enough to require treatment
- Whether you prefer to treat your symptoms with medication or surgery
- Whether you plan to have a child or more children. Medical therapy (hormonal or non-hormonal) does not improve fertility.
- Whether you are close to menopause, when symptoms should stop naturally. If so, it may be worthwhile to control the symptoms with medication until then.
- Whether a second opinion from a doctor would be useful
For mild symptoms, where infertility is not a threat, home treatment (as a supplement to professional care) may ease the discomfort of endometriosis:
- Adopting a healthier lifestyle – good nutrition, regular exercise – may improve symptoms.
- For painful menstrual periods, try an over-the-counter painkiller such as aspirin or ibuprofen. In some cases, prescription painkillers may be necessary.
- Apply heat to the abdomen: use a hot-water bottle or take warm baths. The heat will improve circulation and blood flow, and relieve pain.
- Regular exercise also improves circulation and encourages the production of endorphins, the body’s natural pain relievers.
- Traditional methods, such as Chinese medicine, homeopathy, massage and acupuncture have been suggested, but a large body of evidence has failed to prove their benefit.
Hormone treatment aims to stop ovulation for as long as possible. There are several medications available:
- Oral contraceptives that include oestrogen and progesterone, or progesterone alone (injectable contraceptives). These may control endometriosis as long as they are being used, and may force endometriosis into remission for months or years afterwards.
- Testosterone derivatives (danazol and gestrinome). Danazol suppresses oestrogen levels and increases testosterone in the body. This prevents ovulation and menstruation, and shrinks the uterine lining, preventing new endometrial implants. However, it is rarely used: the side effects (weight gain, acne, muscle cramps, vaginal dryness, body or facial hair growth, deepening of the voice and water retention) are a problem for some women. The drug increases the risk of birth defects, and should be prescribed together with contraceptives.
- Gonadotropin-releasing hormone drugs (GnRH agonists). These should never be the first option. They are expensive and the side effects (eg. menopause symptoms, osteoporosis) are problematic.
- Levonorgestrel intra-uterine system may be effective in management of endometriosis pain.
- Newer agents such as aromatase inhibitors, receptor modulators, vascular disruptive agents and invasion inhibitors are still largely experimental.
Surgery may be necessary to remove endometrial growths if they are causing infertility or intestinal or bladder problems. (Surgery does not always cure infertility, however.)
- Surgery can be performed through a laparoscope (key hole) or laparotomy (open operation). The benefits of laparoscopy are quick recovery and less scarring.
- Surgery for minimal or mild endometriosis does improve a woman’s chance of having a baby, but this is not clear for moderate and severe endometriosis.
- For an endometrioma, cystectomy (removing the cyst) reduces the chance of the cyst coming back and increases chances of conception. However, if the cyst is large, to avoid damage to the ovary, it is better to drain the cyst and prescribe GnRH agonist for three months before removing the cyst.
- In recto-vaginal endometriosis, surgical removal of the nodule will alleviate pain, and may also improve the chance of conception by allowing more frequent intercourse.
- Hysterectomy is not recommended for treatment of endometriosis, and should only be done in women who have other problems associated with the uterus (womb).
A woman who has had surgery for endometriosis and is trying to conceive should be offered assisted reproductive therapy (insemination, in vitro fertilization or ICSI) if there is no pregnancy six to 12 months after surgery (depending on the age of the woman, the duration of infertility, and other possible causes of infertility).
Endometriosis cannot be prevented, especially if there is a family history of the disease. However, using oral contraceptives may reduce the risk of developing endometriosis or prevent it from becoming worse.
Although lifestyle modification and certain nutritional supplements have been suggested to alleviate the symptoms, further research is required to support their use.
Pregnancies before the age of 35 may be protective in some women.
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