Endometriosis
Exam Tips
- Normal pelvic examination or ultrasound does not rule out endometriosis, especially superficial peritoneal disease.
- Think endometriosis in adolescents with severe dysmenorrhoea not responding to simple analgesia/COCP.
- Cyclical bowel or urinary symptoms (for example dyschezia, dysuria, haematuria) are red flags for deep infiltrating disease.
- Pain severity correlates poorly with laparoscopic stage; mild visible disease can still cause major symptoms or infertility.
- In OSCEs, always combine symptom control with fertility planning and psychosocial impact assessment.
- For prescribing stations, state key safety checks: exclude pregnancy before hormonal suppression, screen CHC contraindications, and counsel on NSAID and GnRH adverse effects.
Definition
Endometriosis is a chronic, oestrogen-dependent inflammatory condition in which endometrium-like tissue is found outside the uterine cavity, most often within the pelvis (for example ovaries, uterosacral ligaments, pouch of Douglas, bowel or bladder surfaces). It commonly presents with cyclical or persistent pelvic pain and is associated with reduced fertility, with disease burden not always correlating with lesion size.
Pathophysiology
The mechanism is multifactorial rather than a single-cause disorder. Retrograde menstruation probably allows viable endometrium-like cells to reach the peritoneal cavity, but only a subset develop disease, implying additional contributors such as altered immune clearance, local inflammatory cytokine signalling, neuroangiogenesis, and genetic susceptibility (familial risk is increased). Ectopic implants respond to ovarian hormones, causing repeated bleeding, chronic inflammation, fibrosis, adhesions, and in some patients central sensitization that sustains pain even after lesion removal. Deep disease can infiltrate structures such as bowel, bladder, or ureter, explaining organ-specific cyclical symptoms. See Figure from page 348 (typical pelvic lesion distribution and deep infiltrating planes) in a standard undergraduate UK obstetrics and gynaecology text.
Risk Factors
- First-degree family history of endometriosis
- Early menarche
- Short menstrual cycle length
- Heavy menstrual flow
- Nulliparity
- Low BMI
- Low birth weight
- Outflow tract obstruction (for example cervical stenosis or congenital anomalies)
- White ethnicity
- Autoimmune comorbidity
Clinical Features
Symptoms
- Chronic pelvic pain (cyclical or non-cyclical, typically >=6 months)
- Secondary dysmenorrhoea affecting school/work or daily activities
- Deep dyspareunia
- Cyclical dyschezia or painful bowel motions
- Cyclical urinary pain, dysuria, or haematuria
- Subfertility/infertility
- Bloating, cyclical bowel disturbance, fatigue
Signs
- Pelvic tenderness (especially posterior fornix)
- Tender nodularity of uterosacral ligaments or posterior vaginal fornix
- Reduced pelvic organ mobility/fixed retroverted uterus
- Adnexal tenderness or mass (possible endometrioma)
- Visible vaginal endometriotic lesions (uncommon)
- Abdominal or pelvic mass on examination in selected cases
Investigations
Management
Lifestyle Modifications
- Provide validation, education, and shared decision-making (pain control, fertility goals, and quality-of-life priorities)
- Use a pain and symptom diary to identify cyclical patterns and treatment response
- Regular exercise, sleep optimisation, and heat therapy (for example local heat packs) as adjuncts
- Address mental health impact and sexual pain; consider pelvic physiotherapy and psychological support
- Early referral to specialist endometriosis services when severe symptoms, deep disease, organ involvement, or fertility concerns are present
Pharmacological Treatment
Analgesia (non-hormonal)
- Ibuprofen 400 mg orally three times daily with food (max 2.4 g/day)
- Naproxen 500 mg initially, then 250 mg every 6-8 hours (max 1250 mg/day on day 1, then 1 g/day)
- Mefenamic acid 500 mg three times daily during painful menses
Use the lowest effective dose for the shortest duration; consider PPI gastroprotection if GI risk. Avoid/use caution in peptic ulcer disease, significant renal impairment, NSAID-sensitive asthma, anticoagulant use, and late pregnancy.
Combined hormonal contraception (ovulation suppression and cycle control)
- Ethinylestradiol 30 micrograms/levonorgestrel 150 micrograms one tablet daily, often continuously (extended-cycle regimen)
- Ethinylestradiol 30 micrograms/norethisterone 1.5 mg one tablet daily (continuous use can reduce dysmenorrhoea)
Useful when pregnancy is not desired. Contraindications include current/past VTE, migraine with aura, uncontrolled hypertension, smoking age >=35 years, and active breast cancer.
Progestogen-only options
- Desogestrel 75 micrograms once daily continuously
- Norethisterone 5 mg two to three times daily (specialist-directed continuous regimen)
- Dienogest 2 mg once daily
- Levonorgestrel intrauterine system 52 mg (releases 20 micrograms/day initially, licensed up to 8 years for contraception)
Often first-line hormonal suppression where oestrogen is unsuitable. Counsel regarding irregular bleeding, mood change, acne, and potential delay in return to fertility with injectable progestogens.
GnRH analogues (usually second-line/specialist care)
- Goserelin 3.6 mg subcutaneously every 28 days
- Leuprorelin 3.75 mg intramuscularly monthly
- Triptorelin 3 mg intramuscularly monthly
Induces hypo-oestrogenic state; typically combine with add-back HRT to reduce vasomotor symptoms and bone loss. Exclude pregnancy before starting; monitor bone health with prolonged therapy and use specialist supervision.
Surgical / Interventional
- Laparoscopic excision or ablation of endometriotic lesions for pain and diagnosis
- Laparoscopic ovarian endometrioma cystectomy (preferred over drainage alone due to lower recurrence)
- Adhesiolysis where adhesions contribute to pain or distortion
- Complex multidisciplinary surgery for deep infiltrating bowel/bladder/ureteric disease in specialist centres
- Definitive surgery (hysterectomy with or without bilateral salpingo-oophorectomy) only for selected refractory cases after completed family and counselling on persistent pain risk
Complications
- Endometrioma formation and potential rupture
- Subfertility/infertility (including with mild disease)
- Pelvic adhesions and distorted anatomy
- Chronic pain syndromes and central sensitization
- Bowel obstruction (partial or complete) in severe infiltrative/adhesive disease
- Reduced quality of life, sexual dysfunction, mood disorders, reduced work productivity
- Small absolute increase in risk of some malignancies (notably ovarian cancer), though lifetime absolute risk remains low
Prognosis
Course is variable: many patients have chronic relapsing symptoms beginning in adolescence, and symptoms often improve after menopause, though not universally. Lesions may regress, remain stable, or progress; medical and surgical treatment can substantially reduce symptoms but are not curative. Recurrence after surgery is common and reported rates vary widely (approximately 6-67%), so long-term follow-up and individualized care are important.
Sources & References
🏥BMJ Best Practice(3)
💊BNF Drug References(9)
- Buserelin[management.pharmacological]
- Dienogest[management.pharmacological]
- Goserelin[management.pharmacological]
- Leuprorelin acetate[management.pharmacological]
- Linzagolix[management.pharmacological]
- Nafarelin[management.pharmacological]
- Norethisterone[management.pharmacological]
- Triptorelin[management.pharmacological]
✅NICE Guidelines(1)
- Endometriosis[overview]
📖Textbook References(3)
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1281, 1282)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1418)[context]
- [Williams, Bailey and Love's Short Practice of Surgery] Norman Williams, Christopher Bulstrode, P Ronan O'Connell - Bailey & Love's Short Practice of Surgery 26E (2013, CRC Press) - libgen.li.pdf(pp. 1352, 1353)[context]