see also

• gynaecology
• RIF or pelvic pain
• LIF or pelvic pain
• dysmenorrhoea
• chronic pelvic pain in women

• endometriosis is defined as the presence of endometrial glandular and stromal tissue outside the uterine cavity.
• endometriosis affects about 10% of all women of reproductive age and up to 50% of those with infertility
• It is the most common cause of chronic pelvic pain in adolescent girls, especially those whose pain is not relieved by medical therapy.
• endometriosis is usually found in the pelvis – particularly in the Pouch of Douglas, on the ovaries, on the bladder and on the surface of the bowel (including the appendix).
• It can take a number of forms, such as:
  • active lesions (which look like blood blisters)
  • adhesions (especially around the sigmoid colon and the left adnexae)
  • peritoneal distortion due to the presence of deep deposits (pocket formation)
  • large blood collections (endometriomas).
  • its presence within the bowel itself can cause rectal bleeding.
  • it can also develop in an abdominal scar following Caesarean section or hysterectomy.
• the aetiology, pathophysiology and natural history of this disease are still poorly understood despite extensive research
  • The two most popular theories of causation are that:
    1. Nests of embryonic cells in the pelvic peritoneum become transformed into islands of ectopic endometrium, which then become active after menarche
    2. Reverse menstruation carries small pieces of endometrial tissue into the pelvis via the Fallopian tubes and this tissue becomes implanted into the peritoneum of genetically susceptible individuals.
• the ectopic endometrial tissue is functionally active, invasive, hormone dependent and shows regression with anti-oestrogen therapy.
• endometriosis is an enigma. The severity of the disease is not necessarily matched by the extent of the symptoms.
  • It is not uncommon to find severe endometriosis in asymptomatic women who are being investigated for infertility and yet there are some patients with minimal disease who suffer intense pelvic pain.

• even minimal disease can cause infertility, but the mechanism by which this happens is still poorly understood.
• the quality of an embryo (ie, its ability to develop and implant normally) is reduced by the presence of endometriosis.
• This phenomenon appears to be related to altered concentrations of progesterone, interleukin-6 and vascular endothelial growth factor (VEGF) within the follicle itself. It should be noted that VEGF is vital to the successful implantation of an embryo because it is primarily responsible for the growth of new blood vessels.

• Ovarian Cancer Association Consortium (OCAC)study published in 2012 suggests patients with a history of endometriosis have:
  • 3x risk of clear-cell ovarian cancers
  • more than double the risk of endometrioid tumours
  • 2x risk of low-grade serous ovarian cancers

• largely unknown
• genetic factors
  • Mendelian randomization analysis (MR) suggests a causal effect of depression on endometriosis, and it was found that at least 22 genes associated with both endometriosis and depression (which is twice as high in these patients) appear to be related to genes linked to conditions involving the gastric mucosa, like gastritis, peptic ulcer and gastroesophageal reflux disease, or GERD. These genes were related to 'cell-cell adhesion', 'inositol phosphate metabolism', 'Hippo-Merlin signaling dysregulation' and 'gastric mucosa abnormality'. ¹⁾
    • and the low FODMAP diet seems to help

• The classical symptoms of dysmenorrhoea, pelvic pain, deep dyspareunia, mid-cycle bleeding and infertility may present in any combination, thus causing confusion with pelvic inflammatory disease and inflammatory bowel disorders.
• there may be an association with dysautonomia syndromes but this requires further research to demonstrate

• in 2019, a new DNA blood test, the Mitomic Endometriosis Test, is said to be 90% sensitive in detecting endometriosis even in its early stages

• the only way to prove its presence is by direct visualisation and this is usually achieved by laparoscopy.

• response to a 2 month trial of a GnRH agonist such as inhaled Nafarelin which induces a menopause-like state may be a useful diagnostic option in the older patient
• risk of osteoporosis which is largely reversible upon cessation
• small risk of pulmonary fibrosis

• The serum level of CA-125 is increased in a variety of gynaecological conditions including endometriosis, but this test is of limited value because of its low sensitivity.
• Whilst a high quality transvaginal scan can almost always detect (or exclude) ovarian endometriomas and other pelvic masses, it cannot accurately define adhesions and it cannot 'see' smaller lesions.

• HCG to exclude pregnancy
• consider Ix to exclude pelvic inflammatory disease (PID)
• pelvic USS to exclude other gynaecologic causes

• if symptoms are suspicious of endometriosis then referral to gynaecology for consideration for diagnostic laparoscopy with uterine biopsy (to detect adenomyosis) +/- laparoscopic Rx of endometriosis lesions.
  • The major advantage of laparoscopy is that conservative surgical treatment can be undertaken at the same time during the procedure, but the operation does carry with it a small risk of significant complications, such as an injury to bowel or a ureter.
  • If endometriosis is suspected, a pelvic ultrasound scan is normal and the patient does not wish to conceive, then a trial of drug therapy may be offered as an alternative to laparoscopy
  • There is no role for hormonal drug therapy in the treatment of endometriosis-related infertility.
    • This is not only because such treatment does not improve fertility, but also because it prevents ovulation, which only further delays conception.

• Unfortunately, there is often a significant wait for surgical treatment in a public hospital and thus many patients will require pain management in the meantime.
• use of non-steroidal anti-inflammatory drugs and simple pain, analgesia and analgesics is the most appropriate therapy in these circumstances
• If menorrhagia is an accompanying symptom, then the use of tranexamic acid to reduce blood loss during menstrual periods is also appropriate.

• The amenorrhoea produced by pregnancy and lactation is very effective in suppressing endometriotic deposits and may lead to long-term relief of symptoms.
• The use of a progestogen-only pill, such as norethisterone, as a contraceptive during lactation adds to this effect.
• However, endometriosis is notorious for being a recurring problem and the remission may only be temporary.

• The primary aim of hormone therapy is to suppress the activity of endometriotic implants but this treatment can also lead to atrophy of these deposits in the long term. Unfortunately, all of the available drugs have the potential to cause significant side effects, which can result in non-compliance and thus limit their long-term usefulness.

• combined OCP used continuously
  • to produce amenorrhoea although breakthrough bleeding may occur
• progestogen such as dydrogesterone or dienogest
  • This therapy lacks the potential side effects of oral oestrogen but significant breakthrough bleeding is common, and, if that occurs, most women will stop using the drug.

• Danazol and gonadotrophin releasing hormone agonists (GnRH agonists) are very effective drugs but they are also quite expensive and they are only subsidised through the PBS for visually proven endometriosis.
• Their use is therefore usually limited to those women who have already had a laparoscopy and where there has been a recurrence of symptoms such as dysmenorrhoea. Because the long-term use of these drugs causes osteoporosis, they are generally taken for no longer than 6 months.

• UK RCOG endometriosis update
• endometriosis.org - useful site for patients