Endometriosis is a condition where the lining of the womb is outside the womb cavity. Adenomyosis is the term used to describe endometriosis in the muscle of the womb.

Incidence

• Endometriosis occurs in 2 – 4 % of the premenopausal female population.
• Endometriosis is 10 times more common in infertile women.

Age

• The onset of endoemtriosis is usually 2 - 8 years after menarche.
• Symptoms resolve spontaneously in the menopause. However, symptoms can persist in HRT users.

Geographic

• Diagnosis is more commonly made in Western women.
• This may be a real racial difference or due to access to medical care.

Aetiology

• There are two theories for the aetiology of endometriosis.
• Aetiology is probably a combination of both mechanisms.
• Sampson’s implantation theory;
  • Retrograde menstruation and implantation into pelvis.
  • Does not account for endometriosis found in distant sites (e.g. lung).
• Meyer’s coelomic metaplasia theory;
  • Cells from coelomic membrane transform to endometrial cells.
  • Transformation by a process known as metaplasia caused by a stimulus such as hormones or inflammation.

 

Pathology

• Classically seen as red and inflamed lesions or small ‘gun-shot’ spots.
• Most commonly occurs in the pelvis.
• Can occur in other sites such as the lung or bowel.
• Can cause fibrosis and pelvic adhesions.
• When endometriosis occurs on an ovary it can cause a cyst.
  • As bleeding occurs into an endometriotic cysts it enlarges.
  • As the blood in an endometriotic cysts breaks down it becomes the colour and consistency of melted chocolate – Chocolate cysts.
• Endometriosis is associated with infertility for the following reasons;
  • Can cause Fallopian tube and fimbrial damage.
  • May also cause anovulation due to adhesions or luteinisation of unruptured follicles preventing the release of an oocyte.
  • There may also be an effect of inactivating spermatozoa by antibodies in women with endometriosis. Furthermore, there are many macrophages associated with endometriosis that may phagocytose sperm.
  • Painful intercourse (dyspareunia) in women with endometriosis may result in a reduced frequency of coitus and therefore sub-fertility.

Staging

• Staged according to the American Fertility Society scoring system based on laparoscopic findings.
• This complete scoring system is beyond the scope of that required for finals but a student should know that the score increases with;
  • ‘Deep’ over ‘superficial’ endometriosis.
  • Obliteration of the Pouch of Douglas
  • ‘Dense’ over ‘Filmy’ adhesions
• Dependant on the score, women are classified as having either ‘minimal’, ‘mild’, ‘moderate’ or ‘severe’ endometriosis.
  • Women with obliteration of the Pouch of Douglas automatically get a score consistent with ‘severe’ endometriosis.
  • Women with ‘minimal’ or ‘mild’ endometriosis can have quite severe symptoms. Equally, women with ‘severe’ endometriosis can be asymptomatic. However, symptoms are usually worse with more severe endometriosis.

Clinical features

• Symptoms that women have include;
  • Dysmenorrhoea (pelvic pain during or around menstruation). Classically, this is worse during the first few days of menstruation and a few days before the onset.
  • Pelvic pain. A pelvic pain unrelated to the menstrual cycle can occur as a result adhesion formation. There is also evidence that women with Irritable Bowel Syndrome (IBS) have exacerbations of there IBS related symptoms due to cyclical irritatation from endometriosis.
  • Dyspareunia. Painful intercourse is a classical feature of endometriosis. This is a particular problem in women with endometriosis over the uterosaccral ligaments and in the Pouch of Douglas. It is normally worse just before and during menstruation.
  • Menorrhagia. Women with endometriosis are more likely to complain heavy periods. This may be related to annovulatory cycles.
  • Symptoms from endometriosis at distant sites. Rarely, endometriosis can occur at distant sites such as the lung or bowel. This can cause cyclical bleeding from these sites resulting in symptoms such as haemoptysis and malaena.
• Clinical signs are not pathognomonic as there are many differentials in the diagnosis of pelvic pain (causes boxE1). However, certain signs may aid diagnosis;
  • Abdominal tenderness. Many women have lower abdominal tenderness on abdominal examination. This is predominantly suprapubic and worse just before and during menstruation.
  • Retroverted uterus. On vaginal examination, the uterus may be fixed and retroverted in women with severe endometriosis.
  • Uterosacral nodularity & tenderness. When endometriosis is present on the uterosaccral ligaments, vaginal examination may reveal thickening or nodularity. There is often tenderness around the ligaments just before or during menstruation.
  • Pelvic mass. If an endometrioma is present this may be palpated during pelvic examination.
• Endometriosis is diagnosed at laparoscopy. However, other radiological tests can be useful in making the dagnosis;
  • Ultrasound. This can often identify endometriomas but most endometriosis is not visible on ultrasound. Subtle signs caused by endometriosis are sometimes visible to the trained eye such as reduced mobility of pelvic organs.
  • MRI. MRI can occasionally identify large nodules deep in the rectovaginal septum. As with ultrasound, most endometriosis is not visible on MRI scans.
  • Laparoscopy. This is the mainstay for diagnosing endometriosis. Endometriotic lesions can be seen as black spots, ‘chocolate cysts’, reddened areas, new vessel formation, and clear ‘sago’ blisters. Classical sites include the ovary, para-ovarian fossae, Pouch of Douglas, uterosaccral ligaments, other pelvic surfaces.

Management

• All medical treatments suppress ovulation and are unsuitable for women wishing to conceive.

• To avoid inadvertent administration of drugs during pregnancy it is advised to commence treatment within the first two days of menstruation.

• Medical treatments used are as follows;

  • Progesterones. High dose progesterones such as Provera and Nor-ethisrerone can be taken to obliterate the menstrual cycle. This causes decidualisation of the endometriotic deposits and also helps by removing cyclical symptoms.

  • Combined oral contraceptive pill. The combined pill often helps with symptoms from endometriosis. Monophasic pills (those with the same dose of oestrogen and progesterone for the 21 pill days) can be taken continuously (without a seven day break) to prevent the occurrence of withdrawal bleeds. When three packets are taken in a row it is called ‘tri-cycling’. This obliterates cyclical symptoms.

  • GnRH analogues. GnRH analogues can be taken as a nasal spray or as an inection. They cause a temporary medical menopause by preventing the release of gonadotrophins. The can cause hot flushes and night sweats which can be relieved with taking hormone replacement therapy in conjunction. This is called ‘add back HRT’ and causes reactiviation of endometriosis in 15% of cases.

  • Aromatase inhibitors. Examples include anastrozole and letrozole. They prevent peripheral aromatisation of androgens to oestrogens. It works by withdrawal of the oestrogen stimulus to endometriosis and is usually prescribed in conjunction with GnRH analogues.

  • Danazol & Gestrinone. Danozol and Gestrinone are drugs with androgenic, anti-oestrogenic, and anti-progestogenic properties. They have side effects of hirsuitism and voice deepening and are rarely used now.

• Surgical treatment involves either direct treatment to endometriosis or removal of the hormonal stimulus.

  • Laparoscopic ablation. This can be done by LASER, diathermy, Helica, or harmonic energy during laparoscopy. Often patients have to undergo a number of operations over a number of years.

  • Laparoscopic excision. When large nodules of endometriosis exist, they can be excised and sent for histology.

  • Ovarian cystectomy. Endometriomas can be removed by ovarian cystectomy. If the endometrioma is drained, it invariably recurs and the base of the cyst should either be ablated or excised.

  • Hysterectomy and bilateral salpingoophorectomy. Hysterectomy and bilateral salpingo-oophorectomy removes local endometriosis and the hormonal stimulus from the ovaries.

Prognosis

• Endometriosis is a self-limiting condition that resolves during the menopause.