Early diagnosis of endometriosis can help intercept the course of the disease progression
Endometriosis is the most common cause of chronic pelvic pain in women in industrialised countries. It can be greatly variable in its presentation and can date back to the teenage years in its onset of symptoms.
It is an enigmatic, chronic and potentially recurring disease, with the prevalence estimated at about 10% to 15% in women of reproductive age, but the true prevalence may be higher as the diagnosis can be made definitively only with surgery. The prevalence is up to 50% in women who present with infertility that may or may not be accompanied by pelvic pain.
Awareness of endometriosis has grown among women over the past few decades thanks to magazines, online articles, social media and advocacy groups such as EndoActive. Today, girls and women are more likely to present to a GP seeking an explanation for their dysmenorrhoea and chronic pelvic pain.
The management of endometriosis has also changed significantly over the last few decades, and early diagnosis allows the interception of the natural course of disease progression through timely intervention, sparing young women decades of pelvic pain and preserving their fertility.
Definition and aetiology
The aetiology of endometriosis, defined as ectopic endometrium, is considered multifactorial, with genetics, immunology, environment, anatomy (reproductive tract occlusion such as imperforate hymen), and delay in childbearing1,2 all playing a possible part.
A woman with a sister or a mother with proven disease has eight times the risk of developing endometriosis, compared to a woman with no family history.
There is growing evidence that endometriosis is primarily a disease of the endometrium, as functional and immunological disturbances in the endometrium appear to predate the development of endometriosis lesions in the pelvis. The key anomalies are expression of intercellular adhesion molecules, presence of local aromatase enzyme activity, decreased apoptosis, increased angiogenesis and neurogenesis. These factors are responsible for attachment, viability, growth and innervation of fragments of endometrium at ectopic sites.
A number of theories seek to explain the various types of endometriotic disease that can occur in the pelvis.
The coelomic metaplasia theory refers to the development of endometriosis from embryonic rests, i.e. fragments of embryonic tissues that have been retained following the period of embryonic development. This may explain the deep fibrotic endometriosis that develops in the rectovaginal septum below the peritoneum and causes adhesion of the rectum to the vagina and uterus.
The retrograde menstruation theory stipulates that shed endometrial cells can implant in the pelvis.3 This theory presumes that an abnormality in the endometrium or the immune system
must be present, leading to the failure of the shed endometrial cells to be removed from the pelvis.
Clinical manifestations
Endometriosis causes chronic pelvic pain and infertility in some women. It is highly variable in terms of the severity of pain, incidence of infertility, progression of disease, and rate of recurrence. The majority of women suffer from primary dysmenorrhoea or pelvic pain outside menses, but a minority will have no pain and will present with a history of infertility.
Other common symptoms include abnormal uterine bleeding, pain radiating to the anterior thigh, abdominal bloating and lethargy. Pain on opening bowels usually represents advanced endometriosis involving the rectum or the peritoneum of the Pouch of Douglas overlying and adjacent to the rectum. Cyclical urinary symptoms are rare as the bladder is far less commonly affected by endometriosis than the bowel.
Because of the wide and variable spectrum of the symptoms of endometriosis, a high index of suspicion is advised when a woman presents with pelvic pain, especially when this pelvic pain has atypical characteristics.
It is important to note that two-thirds of women with endometriosis have symptoms that first manifest before the age of 20, therefore the diagnosis should be considered in teenage girls presenting with pelvic pain. In contrast to older women who present with cyclical dysmenorrhoea, 90% of younger women have acyclical pain with or without dysmenorrhoea.
Co-morbidities are common in women with endometriosis, especially in adolescents, because of the chronic nature of the pain and the often lengthy delay in diagnosis. Referral to a gynaecologist should be considered for adolescent and young women for a laparoscopy when:
• The pain is unresponsive to analgesia or the pill, and/or
• She has three or more visits to the GP or hospital with pelvic pain, and/or
• Intermittent bed rest or analgesia has been required for more than three months
With the use of these criteria for specialist referral, about 70% of adolescents undergoing laparoscopy will be diagnosed with endometriosis.
Diagnostic approach
A timely consideration of the possibility of endometriosis is perhaps the most important aspect of a woman’s management. Endometriosis requires ongoing management until menopause, so a good relationship between patient and GP has a real potential to significantly influence her quality of life.
The following approach by the GP would give a woman the best chance of early diagnosis of endometriosis:
1. Discuss the possibility that dysmenorrhoea or pelvic pain may be due to endometriosis. A pelvic examination and ultrasound can help to make the diagnosis of advanced disease. However, for most women, the examination and ultrasound will be normal. Early endometriosis is not palpable on examination and there are no specific changes on ultrasound.
2. Perform a thorough bimanual pelvic examination. On pelvic examination in a normal pelvis, the uterus is mobile and the posterior vaginal fornix, when palpated deep behind the cervix in a slow sweeping motion, is smooth and mobile.
In advanced endometriosis, there is nodularity of the posterior vaginal wall indicating endometriosis of the uterosacral ligaments and/or vaginal wall. Nodularity palpable in the vagina deep behind the cervix would suggest advanced endometriosis of the rectovaginal septum and hence rectal disease.
In some women, the examination may elicit only tenderness in the vagina without palpable nodularity, as the lesions are too small. As the examination may elicit pain, it is important to explain the reason and purpose of the examination to the patient first and to obtain informed consent. In most women, the pelvic examination will be normal.
3. A specialised transvaginal endometriosis ultrasound complements the pelvic examination. It is performed following bowel preparation with an enema to empty the rectum and sigmoid colon. It may reveal markers of advanced disease such as endometrioma (typical homogeneous echogenic appearance of an ovarian cyst), nodularity of the uterosacral ligament(s), or nodule(s) on the rectum. Normally, the rectum slides freely behind the vagina during the ultrasound examination. A “negative sliding sign” means that the rectum is adherent to the vagina by a nodule of endometriosis, and hence the Pouch of Douglas is obliterated by the adherent rectum. The indications for this ultrasound are:
• Routine investigation of pelvic pain to assess presence of the above markers for advanced endometriosis when there is high suspicion of endometriosis;
• Assessment of the extent of rectal endometriosis when a nodule is palpable in the posterior vaginal fornix on bimanual examination. This will assist in planning for surgery with a colorectal surgeon and discussing bowel surgery and its implications with the woman.
4. A referral for laparoscopy to a gynaecologist specialising in endometriosis is indicated when:
• Positive findings on examination and/or ultrasound are highly suggestive of endometriosis;
• High index of suspicion of endometriosis based on history, i.e. severity of dysmenorrhoea, symptomatology typical of endometriosis, positive family history, chronicity of pelvic pain;
• Investigation of infertility with or without a history of pelvic pain.
Treatment in general practice
As discussed above, pelvic examination and ultrasound are usually normal in endometriosis, despite moderate to severe pelvic pain. A discussion with the woman may start with the fact that she may have endometriosis but it’s hard to know for sure at this stage.
The relationship between endometriosis and infertility in some women should be explained. This could help her make a decision as to whether she would consider a diagnostic laparoscopy at some stage. Risks and benefits should be explained, along with the expectations of outcomes of the medical and surgical options. This discussion can span a number of consultations, as a woman may prefer to pursue conservative options with analgesia and hormonal therapy first.
Generally, if pelvic pain persists after treatment with the pill or hormonal intrauterine device, she will return to discuss surgery. Fortunately for many women, the above treatment may adequately control their pain, and they may choose to continue with this approach.
Medical therapeutic options
Analgesia is instituted with nonsteroidal anti-inflammatory medications. These can be supplemented by paracetamol or compound codeine alternatives. Medical therapy of endometriosis requires suppression of ovulation and/or inducing a state of amenorrhoea/hypomenorrhoea with the continuous regimen of the combined contraceptive pill or the Levonorgestrel-releasing intrauterine device (Mirena).4 Etenogestrel subdermal implant (Implanon) and medroxyprogesterone acetate (Depo-Provera) are acceptable alternatives. For some young women with aggressive and advanced disease, simultaneous use of the Mirena and Implanon has been advocated.5
Following laparoscopic excision of endometriosis, the Mirena IUD is recommended for long-term suppression of endometriosis and reduction of the risk of recurrence, unless infertility was the presenting symptom.
Laparoscopy
Referral to a gynaecologist does not necessarily have to be for a laparoscopy. It can also be for a second opinion on the aetiology of pelvic pain and the likelihood of endometriosis. The gynaecologist would proceed with the same steps for the diagnosis and management as a GP.
Indications for laparoscopy are investigation of pelvic pain and the diagnosis or exclusion of endometriosis. If endometriosis is present, indications for surgical excision are as follows:
1. Management of pelvic pain and other symptoms;
2. Prevention or management of infertility;
3. Exclusion of the rare risk of ovarian cancer in endometriomas.
The risk of recurrence of endometriosis after excision is about 30% at three years.
The outcome of laparoscopy in endometriosis depends on the surgical skills of the gynaecologist. It should be performed by a specialist in the excision of endometriosis with considerable experience in complex pelvic surgery.
If endometriosis is found at laparoscopy, it should be excised and not diathermy ablated. Partial excision usually results in persistent or worsening pain, anxiety and depressive symptoms as the woman may have to undergo multiple laparoscopies.
An untrained eye can miss early endometriosis in adolescent girls, as it can be subtle and appear merely as small vesicular lesions on the peritoneum.
Similarly, advanced disease with deeply infiltrating fibrotic endometriosis underneath the peritoneum in the Pouch of Douglas may be missed by an inexperienced surgeon.
The laparoscopy should be planned carefully and may require the expertise of a colorectal and/or urologist surgeon in cases of rectal, ureter, or bladder involvement.
The woman should be informed of all potential surgical risks, postoperative expectations in regards to pregnancy and the degree of expected alleviation of her pelvic pain.
The improvement in dysmenorrhoea is variable but can be at least 50% with complete excision of the endometriosis. Women with infertility may or may not become pregnant naturally following surgery, and hence IVF should be discussed as a future option.
Long-term care
As endometriosis is an oestrogen-dependent disease, women need a holistic long-term management plan through the lifetime until menopause.
Such a plan can be tailored to the woman with her GP and will include the gynaecologist and possibly a combination of other healthcare professionals depending on her symptoms.
Women often develop vaginismus secondary to dyspareunia from endometriosis, and surgery alone is unlikely to resolve this symptom, which requires sexual counselling by a medical sex therapist. Chronic pelvic pain may also require ongoing support by a pain specialist and a physiotherapist, as well as advice on regular exercise and healthy nutrition.
Clinical Associate Professor Nesrin Varol is a gynaecologist at Royal Prince Alfred Hospital, Sydney and Director at Sydney Gynaecology and Endometriosis Centre
References:
1. Garry R. Is insulin resistance an essential component of PCOS? The endometriosis syndromes: a clinical classification in the presence of aetiological confusion and therapeutic anarchy. Hum Reprod 2004; 19: 760-768.
2. Treloar SA, O’Connor DT, O’Connor VM, et al. Genetic influences on endometriosis in an Australian twin sample. Fertil Steril 1999; 71: 701-710.
3. Sampson JA. Peritoneal endometriosis due to the menstrual dissemination of endometrial tissue into the peritoneal cavity. Am J Obstet Gynecol 1927; 14: 422-469.
4. Wong AY, Tang LC, Chin RK. Levonorgestrel-releasing intrauterine system (Mirena) and depot medroxyprogesterone acetate (Depo-Provera) as long-term maintenance therapy for patients with moderate and severe endometriosis: a randomised controlled trial. Aust N Z J Obstet Gynaecol 2010;50:273-9.
5. Al-Jefout M, Palmer J, Fraser IS. Simultaneous use of a levonogestrel intrauterine system and an etonogestrel subdermal implant for debilitating adolescent endometriosis. Aust N Z J Obstet Gynaecol 2007;47:247-9.
