Endometriosis: Diagnosis and Management

Definition and Epidemiology

• Endometriosis: presence of endometrial-like tissue outside the uterus
• Affects approximately 10% of women of reproductive age
• Common sites: ovaries (endometriomas / "chocolate cysts"), peritoneum, uterosacral ligaments, pouch of Douglas, rectovaginal septum, bladder
• Rare sites: diaphragm, lungs, surgical scars
• Average diagnostic delay: 7-8 years from symptom onset

Symptoms

• Dysmenorrhoea: cyclical pelvic pain, often worsening over time
• Dyspareunia: deep pain during intercourse (particularly with deep infiltrating endometriosis)
• Chronic pelvic pain: non-cyclical pain that may be constant
• Dyschezia: pain on defecation (rectovaginal/bowel endometriosis)
• Dysuria: cyclical urinary symptoms (bladder endometriosis)
• Subfertility: affects 30-50% of women with endometriosis
• Cyclical rectal bleeding: if bowel wall involved
• Fatigue: common and often underappreciated

Diagnosis

Clinical Assessment

• Pelvic examination: tenderness, nodularity in posterior fornix, fixed retroverted uterus, adnexal masses
• Examination may be normal — does not exclude endometriosis

Investigations

• Pelvic USS: first-line imaging; can detect endometriomas (>90% sensitivity) and deep endometriosis
• MRI: useful for deep infiltrating endometriosis, rectovaginal nodules, ureteric involvement
• Laparoscopy: gold standard for definitive diagnosis; allows biopsy and simultaneous treatment
• CA-125: may be elevated but NOT recommended for diagnosis (poor sensitivity and specificity)
• Do NOT delay empirical treatment while awaiting diagnostic laparoscopy

Medical Management

Analgesics

• Paracetamol and NSAIDs (e.g. mefenamic acid, ibuprofen, naproxen) — first-line
• Neuropathic pain agents (amitriptyline, gabapentin) for chronic pain component

Hormonal Treatments

• Combined oral contraceptive (COC): cyclical or continuous use; suppresses ovulation and reduces menstrual flow
• Progestogens: medroxyprogesterone acetate, norethisterone, dienogest — induce decidualisation and atrophy
• Levonorgestrel IUS (Mirena): effective for pain; considered for at least 2 years
• GnRH agonists (leuprorelin, goserelin): induce pseudo-menopause; effective but limited to 6 months without add-back HRT (bone loss risk); add-back therapy extends use up to 2 years
• GnRH antagonists (elagolix, relugolix): oral medications, newer option with dose-dependent oestrogen suppression
• Do NOT use danazol (androgenic side effects) or gestrinone routinely

Treatment Approach

• Empirical hormonal treatment can be started without laparoscopic confirmation
• Trial for 3-6 months; if no improvement, consider alternative or surgical management
• Hormonal treatments suppress but do not cure endometriosis — recurrence on cessation

Surgical Management

Laparoscopic Surgery

• Excision preferred over ablation for peritoneal endometriosis (lower recurrence rate, better histological confirmation)
• Endometrioma excision (cystectomy): preferred over drainage/ablation (lower recurrence); but may reduce ovarian reserve
• Deep infiltrating endometriosis (DIE): complex surgery — should be performed in specialist endometriosis centres (BSGE accredited centres)
• Bowel endometriosis: may require segmental bowel resection (multidisciplinary with colorectal surgeon)
• Ureteric endometriosis: ureterolysis or reimplantation (with urologist)

Surgical Considerations

• Inform patients about impact on ovarian reserve (especially bilateral cystectomy)
• Post-operative hormonal treatment may reduce recurrence
• Recurrence rate after surgery: approximately 20-40% within 5 years
• Hysterectomy with bilateral salpingo-oophorectomy: definitive treatment for women who have completed their family (but endometriosis can rarely recur even after BSO)

Fertility and Endometriosis

• Endometriosis reduces fertility through multiple mechanisms: anatomical distortion, chronic inflammation, altered peritoneal environment, reduced oocyte quality
• Mild-moderate endometriosis: surgical treatment may improve spontaneous conception
• Severe endometriosis: IVF often required
• Do NOT use hormonal suppression as a fertility treatment (delays conception)
• Endometriomas >4cm: consider cystectomy before IVF (but counsel about ovarian reserve)

Adenomyosis

• Endometrial tissue within the myometrium
• Associated with: heavy menstrual bleeding, dysmenorrhoea, subfertility
• Diagnosis: MRI (junctional zone >12mm) or TVUS (asymmetric myometrial thickening, heterogeneous echotexture)
• Management: similar to endometriosis (hormonal suppression, IUS, or hysterectomy)

Important Facts for MRCOG

• 10% of reproductive-age women; average diagnostic delay 7-8 years
• Excision preferred over ablation for peritoneal disease
• Laparoscopy is gold standard for diagnosis
• GnRH agonists: maximum 6 months without add-back HRT
• LNG-IUS effective for endometriosis pain
• CA-125 NOT recommended for diagnosis
• Surgical excision of endometriomas preferred but may reduce ovarian reserve
• Deep endometriosis surgery: specialist centres only
• Hormonal suppression does not improve fertility

Source: NICE NG73 (2024)

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Clinically reviewed by NHS obstetricians and gynaecologists · Source last updated 2024

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