Symptoms are related to the endometrial tissue at aberrant sites undergoing changes in response to cyclical hormonal fluctuations which occur throughout the reproductive life of the woman
Endometriosisisacommon and painful condition affecting women. The normal lining of the uterus or womb is called endometrium. When endometrium is present as implants or deposits at locations other than the cavity of the uterus the condition is called endometriosis. Estimates of its prevalence vary from about 1% to 10% of all women in their reproductive age. Endometriosis is the cause for much pain and misery with pain and infertility being the leading complaints. Endometriosis is often overlooked with an average time from initial symptoms to diagnosis of endometriosis being as much as 10 years. The wide variance in prevalence reported in different studies is partly due to endometriosis being overlooked as the true cause of symptoms.
Women during their reproductive period of life have a menstrual period except during pregnancy or when breastfeeding. This is evident as menstrual flow for 2 to 7 days on a more or less monthly basis. Menstrual flow represents shedding of the superficial layer of the endometrium, the internal lining of the cavity of the uterus, in response to cyclical hormonal changes. The uterus is a pear shaped organ with an upper body and fundus and a lower part called the cervix which opens into the vagina. The two fallopian tubes open into the uterus on each side at the fundus. The fallopian tubes serve to convey the ovum or egg from the ovary to the body of the uterus for implantation after fertilization by spermatozoa. In endometriosis, endometrium is present at sites other than the uterine cavity. This aberrantly located endometrium too responds to cyclical hormonal changes and this is the reason that symptoms too tend to be cyclical corresponding to the menstrual cycle. How and why endometrial tissue manages to be located at these aberrant sites is not too clear. One theory is that menstrual blood may flow in a retrograde manner through the fallopian tubes and contained endometrial tissue gets implanted at aberrant sites. Since such retrograde menstrual flow has been noted normally also, it is likely that immune factors that allow such implantation are also involved. In addition to retrograde flow through the fallopian tubes endometrial tissue may also travel to distant sites like the lung or other organs through lymph channels or the blood stream for subsequent implantation. Another theory is that rather than implantation of endometrial tissue, existing tissue at aberrant sites gets converted to endometrial tissue as a result of cyclical hormonal stimulation or that endometrial tissue arises due to a developmental abnormality.
A number of risk factors for endometriosis have been identified. A family history of endometriosis increases risk. Start of menstruation at an early age is another risk factor. Some characteristics of the menstrual cycle such as shorter duration, heavy bleeding or longer duration of bleeding during the period too are associated with a higher incidence of endometriosis. Women who have had more pregnancies appear to be somewhat protected from development of endometriosis while women who have never been pregnant or become pregnant relatively late are at greater risk. Developmental abnormalities related to the uterus and fallopian tubes too impart a risk for endometriosis. Low weight is also a risk factor for endometriosis.
Symptoms are related to the endometrial tissue at aberrant sites undergoing changes in response to cyclical hormonal fluctuations which occur throughout the reproductive life of the woman. Not all women with endometriosis deposits have symptoms. In fact a third of them have no symptoms. The more deeply impacted the deposits, the higher the likelihood of pain and its severity too is linked to the depth of deposits. Like normal endometrial tissue, there is minor bleeding in endometriosis tissue too. This causes an inflammatory response which manifests as pain and tenderness. The inflammatory response may also cause fibrosis with distortion of tissues. Symptoms usually start around the age of 25 years or later. They too occur cyclically, starting a few days before the menstrual period, building up gradually to then subside in a day or two once menstrual flow starts. Site of pain depends mainly on the location of deposits. The pelvis is the usual location for endometriosis and areas close to the uterus such as the ovaries, urinary bladder, ureters, the rectum and colon and the folds and crevices around the uterus are common sites. Less commonly, endometriosis occurs in the upper abdomen and sometimes in the lungs and very rarely in totally unexpected sites such as the brain. Commoner symptoms include menstrual pain, back pain, painful intercourse, pain when passing stools or urine, abdominal discomfort and bloating. The characteristic of these symptoms is the onset or exacerbation of symptoms a few days before the menstrual period and relief once it starts. Some patients may complain of passing blood in urine or in stools, again in a cyclical manner in association with their period. Over time recurrent inflammation may result in scarring and if this involves critical areas such as a bowel loop or the ureter, it could cause intestinal obstruction or damage to a kidney from obstruction to urine flow. Another major problem with endometriosis is that about a third of affected women suffer impaired fertility. Endometriosis also increases risk for cancer of the ovary by a small degree. Since this is a relatively less common cancer the impact is not too great.
The definitive diagnostic test is visualization of endometriosis deposits at laparoscopy along with biopsy. This involves introduction of a slender telescope through a tiny incision in the abdomen. Surgical instruments to manipulate the organs and to carry out surgery are introduced through additional small incisions. This form of keyhole surgery is widely practiced for a variety of gynaecological problems as well as for general surgical procedures for gall bladder stones, appendicitis, hernia, weight loss surgery, etc. Laparoscopy is a surgical procedure and like any surgical procedure there is a small but definite risk associated with it and with the administration of anaesthesia. In well trained and experienced hands this risk is very small. Advantage of laparoscopy is that tissue for histopathology confirmation can also be obtained and therapeutic procedure to destroy problematic endometriosis lesions can also be carried out at the same time. Other tests such as blood tests and imaging tests like ultrasonography and MRI scan are supportive rather than diagnostic in cases of endometriosis, the latter tests being particularly helpful when complications of endometriosis such as bowel obstruction are suspected.
Regarding treatment, the two main issues are preventing or controlling pain and improving fertility where this is affected. Treatment can be medical or surgical. In general, except when there are complications, the primary line opted for is medical with surgery being reserved for refractory cases or for specific indications. Medical therapy is targeted at the cyclical hormonal influences to which endometrium responds. Medical therapy only suppresses endometriosis and there is no possibility of achieving a cure with this line of treatment. Oral contraceptives are one of the treatment options. One type of oral contraception involves taking a pill containing the hormones for 21 days followed by placebo tablets for a week while the other type involves taking the hormones containing pill daily. The continuous type of pill gives better response in controlling endometriosis. An alternative is progestin therapy alone. This may be administered as a tablet, in an intrauterine device containing the hormone or as a depot injection. The menstrual period and the endometriosis lesions are suppressed by this therapy with resultant relief of symptoms. Gonadotrophin releasing hormone therapies which work at the pituitary level is another option. They suppress secretion of LH (leutinizing hormone) and FSH (follicle stimulating hormone) which in turn causes reduction in secretion of oestrogen and progesterone in the body. The result is a premature menopause which is reversed once these medicines are withdrawn. However, this treatment can cause discomforting menopausal symptoms such as hot flashes and also loss of bone and replacement hormonal therapy may have to be considered. Danazol is another hormonal drug fairly effective in endometriosis. A major drawback is potential for androgenic effects like development of acne, oily skin, hair on the face, deepening of voice, weight gain, etc.
Surgically, the endometrial deposits maybe destroyed by laser or electro-cautery, usually during laparoscopy. This sort of surgery does not interfere with future reproduction. If no further pregnancies are desired the uterus may also be removed with or without the ovaries. In the latter case hormonal replacement therapy may be indicated depending on the age of the woman. Women with fertility problems who are desirous of future pregnancies may benefit from corrective surgery in case of fibrosis or other structural abnormalities related to endometriosis.