Endometriosis

Endometriosis is a prevalent inflammatory condition affecting approximately 1 in 10 women of reproductive age. Ectopic endometrial tissue responds to cyclical hormonal changes, leading to localised bleeding, inflammation, fibrosis, and adhesion formation. Common sites include ovaries (forming 'chocolate cysts' or endometriomas), uterosacral ligaments, Pouch of Douglas, and pelvic peritoneum. Extrapelvic involvement can affect the bowel, bladder, or even lungs (catamenial pneumothorax). Patients typically present with a triad of dysmenorrhoea, deep dyspareunia, and chronic pelvic pain. Diagnostic delay is significant, often averaging 7-8 years, as symptoms are frequently dismissed. Management involves analgesia, hormonal suppression, and surgical excision. It's a major contributor to subfertility, implicated in 30-50% of cases.

The exact aetiology is debated. The 'Retrograde Menstruation' (Sampson's Theory) is most accepted: viable endometrial cells flow through fallopian tubes into the peritoneal cavity and implant. However, as this occurs in most women, immune dysfunction (failure to clear ectopic tissue) and genetic predisposition are also implicated. The 'Coelomic Metaplasia' theory suggests peritoneal cells transform into endometrial-like cells. Once implanted, these ectopic lesions are oestrogen-responsive, producing their own oestrogen via aromatase and lacking inactivating enzymes, creating a pro-inflammatory, high-oestrogen microenvironment. Cyclical bleeding from these sites irritates the peritoneum, causing pain and adhesion formation, distorting anatomy and contributing to infertility.

Clinical presentation is highly variable. The hallmark is chronic pelvic pain (>6 months), often cyclical but not exclusively. Dysmenorrhoea frequently starts days before menses. Deep dyspareunia suggests uterosacral ligament or Pouch of Douglas involvement. Other symptoms include dyschezia (painful defecation) or dysuria if bowel or bladder are affected. On examination, findings may include a fixed, retroverted uterus, tender posterior fornix nodules, or palpable adnexal masses (endometriomas). Complications include chronic pain, significant impact on mental health, and subfertility due to anatomical distortion or an adverse follicular environment. Rare catamenial symptoms (e.g., haemoptysis, umbilical bleeding) coincide with menses.

Bedside: Rule out other causes – pregnancy test (ectopic/pregnancy-related pain), urinalysis (UTI), high vaginal/endocervical swabs (PID). Bloods: CA125 may be mildly elevated but is non-specific and not for primary diagnosis. Imaging: Transvaginal Ultrasound (TVUS) is first-line to identify endometriomas and assess for 'sliding sign' (Pouch of Douglas obliteration). MRI Pelvis is used for detailed mapping of deep infiltrating endometriosis (DIE) pre-surgery. Specialty: Diagnostic Laparoscopy is the gold standard, allowing direct visualisation and biopsy of lesions for definitive diagnosis.

Analgesia: First-line are Paracetamol and NSAIDs (e.g., Mefenamic acid, Ibuprofen), ideally started 48 hours before menses. Hormonal: Aim to induce amenorrhoea or thin the endometrium. Options include continuous combined oral contraceptive pill (COCP), progestogens (e.g., Medroxyprogesterone, Mirena IUS, Nexplanon), or GnRH analogues (e.g., Leuprorelin) which induce a 'pseudomenopause' (limited to 6 months unless 'add-back' HRT is used to prevent bone loss). Surgical: Conservative surgery involves laparoscopic excision or ablation of lesions and adhesiolysis. Definitive surgery (hysterectomy and bilateral salpingo-oophorectomy) is reserved for completed families where other treatments have failed. Subfertility management often requires IVF.