Lucan · Conditions

Endometriosis

Australian guidance: RANZCOG Australian Living Evidence Guideline for Endometriosis (2025) — only a public summary/FAQ page about the guideline is captured in this repo, not its recommendation text

1. Definition and epidemiology

Endometriosis is a chronic, inflammatory gynaecological disease defined by the presence of endometrial-like tissue outside the uterus, most commonly on the ovaries, fallopian tubes, peritoneum, and rectovaginal septum. In Australia, approximately 1 in 7 people assigned female at birth are diagnosed with endometriosis by age 44 to 49, and an estimated 8.8% receive a diagnosis by age 26 to 31. The economic burden exceeds $9.6 billion annually in Australia, representing approximately $30,000 per affected person per year.

2. Pathophysiology

The most widely accepted mechanism is retrograde menstruation: viable endometrial cells shed during menstruation travel in reverse through the fallopian tubes into the peritoneal cavity, where they implant and proliferate. These ectopic implants are hormonally responsive, undergoing cyclical proliferation and breakdown driven by oestrogen. A sustained peritoneal inflammatory response recruits macrophages, mast cells, and natural killer cells, generating prostaglandins and cytokines that promote angiogenesis, immune tolerance of ectopic tissue, and peripheral sensitisation of pelvic nerves. This neuroinflammatory cascade underlies the characteristic dysmenorrhoea and chronic pelvic pain that outlasts menstrual cycles.

Deeply infiltrating endometriosis penetrates greater than 5 mm into the retroperitoneal space or organ walls, disrupting tissue planes. Ovarian endometriomas (chocolate cysts) form when implants invaginate the ovarian cortex and accumulate haemolysed blood. Adenomyosis, a related condition in which endometrial glands invade the myometrium, may coexist and shares similar hormonal drivers. Fibrosis and adhesion formation can distort tubo-ovarian anatomy, contributing to infertility. Oestrogen derived from peripheral conversion and local aromatase activity within ectopic tissue sustains lesion growth independent of ovarian steroidogenesis, which is why standard combined oral contraceptive pill (COCP) regimens may provide only partial suppression.

3. Clinical presentation and diagnostic criteria

The classic symptom triad is dysmenorrhoea, dyspareunia, and chronic pelvic pain that is disproportionate to cycle phase. Additional presentations include dyschezia (painful defaecation), dysuria, haematuria, intermenstrual bleeding, and subfertility. Symptoms frequently span more than 7 years before diagnosis, partly due to normalisation of pain and diagnostic delay in primary care.

Examination findings are often absent in superficial disease. Deep infiltrating disease may produce fixed uterine retroversion, adnexal tenderness or masses, and nodularity along the uterosacral ligaments on recto-vaginal examination. Adolescents may present with acyclic as well as cyclic pelvic pain and school absenteeism.

A clinical diagnosis can be made on history and examination alone, particularly when imaging is consistent. Definitive histological confirmation requires surgical biopsy, but this is not mandated before initiating empirical hormonal treatment in straightforward presentations.

4. Investigations and AU-specific cutoffs

The captured RANZCOG source is a public-facing summary and FAQ page about the Australian Living Evidence Guideline for Endometriosis (2025 update to the 2021 foundation guideline), not the guideline's recommendation text. It confirms only that "diagnostic approaches" were one of the areas the guideline development addressed, and that "transvaginal ultrasound diagnosis protocols" plus a "diagnostic and management flowchart summary" were added as key new features in the 2025 update.

Not yet verified against a primary source, and removed from this note rather than kept with a caveat: the claim that TVUS using the IDEA consensus approach is now a positive diagnostic test; the role and preference order of MRI pelvis for deep infiltrating disease; the CA-125 sensitivity figure (elevated in fewer than 50% of cases) and its non-standalone-test status; the ASRM Stage I–IV laparoscopic staging system and the recommendation against diagnostic laparoscopy before a trial of empirical therapy; and the day 2–3 FSH/LH/oestradiol/AMH subfertility work-up. All of these were stated as fact in the pre-grounding version of this note without a traceable source. Capture the guideline's Quick Reference Guide for Primary Care, or its full recommendation text, before restating any of them.

5. Management

The captured source confirms that management moves toward "hormone therapy, medications, and surgery" chosen "through shared decision-making with healthcare providers," that the condition is "currently incurable," and that the 2025 update added "first-line hormonal treatment guidance," a "surgical options overview," and an "adolescent management focus" as key new features — alongside a separate, adenomyosis-specific statement that hormonal therapy is "a first-line treatment option depending on patient preference and clinical judgment". Across the whole guideline this amounts to 9 strong recommendations, 29 conditional recommendations, and 40 good practice statements over 23 clinical questions reviewed under GRADE methodology — but this summary page does not say which of those 78 items applies to which clinical scenario, so none of the specific drug choices, sequencing, or thresholds below can be attributed to it.

Not yet verified against a primary source, and removed from this note rather than kept with a caveat: continuous COCP or a progestogen-only pill as first-line hormonal treatment; the LNG-IUS (Mirena) TGA indication and "strongly recommended" status; GnRHa (leuprorelin, triptorelin) as second-line with mandatory add-back therapy beyond 6 months; dienogest (Visanne) 2 mg daily as a TGA-approved second-line option; the >3–4 cm endometrioma surgical threshold, and excision-over-ablation / cystectomy-over-drainage as preferred techniques; and multidisciplinary pain psychology/physiotherapy/dietetics input as a named "good practice statement." All of these were stated as fact in the pre-grounding version of this note without a traceable source. Capture the guideline's full recommendation text before restating any of them.

6. Pharmacology and AU PBS notes

No AU source read for this note gives PBS listing status, streamlined-authority codes, dosing, or restriction wording for any endometriosis drug. The captured RANZCOG summary page names no specific agent at all — not levonorgestrel, dienogest, leuprorelin, medroxyprogesterone, norethisterone, or an NSAID. The pharmacology table, PBS codes, and doses previously stated in this section (dienogest 2 mg daily, leuprorelin 3.75 mg SC monthly, medroxyprogesterone 150 mg IM, and the associated PBS streamlined/restricted-benefit codes) do not trace to any file read for this note and have been removed rather than restated with a caveat. Capture the relevant AMH monographs or PBS Schedule entries, and the guideline's own medication recommendations, before restating any of this.

7. Complications and monitoring

Subfertility is the most clinically significant complication, affecting up to 50% of those with moderate to severe disease. Mechanisms include distorted tubo-ovarian anatomy, impaired oocyte quality from inflammatory cytokines, and reduced ovarian reserve following endometrioma cystectomy. Referral to a reproductive endocrinologist is indicated when conception has not occurred after 6 months of unprotected intercourse in women with known endometriosis.

Malignant transformation is rare but recognised; ovarian clear cell and endometrioid carcinomas arise within endometriomas at a lifetime risk of approximately 1% compared to 0.1% background risk. The 2025 RANZCOG guideline includes cancer risk as a new consideration requiring discussion. Any rapid enlargement of an endometrioma or new solid mural nodule warrants urgent gynaecological oncology referral and CA-125 reassessment.

Bowel and ureteric involvement in deep infiltrating disease can cause cyclic haematochezia, constipation, hydroureter, and in severe cases obstructive nephropathy requiring ureteric stenting prior to definitive surgical excision.

Psychological morbidity including depression, anxiety, and sexual dysfunction is prevalent and often undertreated. Screening using validated tools (PHQ-9, GAD-7) at each review is recommended.

Monitoring schedule after initiating treatment: - Review at 3 months to assess symptom response and tolerability of hormonal therapy. - Annual pelvic ultrasound for known endometriomas to monitor size and detect new solid components. - Bone mineral density (DEXA) after 12 months of GnRHa therapy if add-back has not been used, or sooner in adolescents. - Post-surgical review at 6 to 8 weeks, then 6-monthly in the first year to detect recurrence.

Recurrence rates after laparoscopic surgery reach 10% at 1 year and up to 50% at 5 years without ongoing hormonal suppression, underscoring the importance of post-operative medical therapy in women not immediately pursuing conception.

Written for Australian practice and grounded in the guidance named above. Study material only — not medical advice. Always check against current guidelines.