Endometriosis

“A condition where endometrial tissue grows abnormally, outside of the uterus, within or outside of the pelvic cavity”

• Intra-pelvic endometriosis sites (more common)
  • Ovaries
  • Fallopian tubes
  • Pelvic peritoneum
  • Uterosacral ligaments
• Extra-pelvic endometriosis sites
  • GI tract
  • Urinary tract
  • Soft tissues
  • Chest

Risk Factors

• First-degree relative with endometriosis
• Prolonged exposure to oestrogen – early menarche or late menopause
• Elevated exposure to oestrogen
• Obstruction of menstrual outflow (Müllerian anomalies)
• Short menstrual cycles (< 27 days)
• Heavy menstruation that lasts >7 days
• Low BMI
• Nulliparity

Aetiology

• Retrograde menstruation (menstrual blood containing endometrial cells back-flowing into the pelvic cavity via the fallopian tubes)
• Transformation of other cell types (peritoneal and embryonic) to endometrial cells
• Adherence of endometrial cells to scar tissue post-surgery (i.e. after Caesarean section)

Pathophysiology

• Not fully understood – the most widely accepted hypothesis is that endometrial cells are transported from the uterine cavity during menstruation, where they are implanted in ectopic sites

Clinical Presentation

• Dysmenorrhoea
• Dyspareunia – can be progressive or chronic
• Other symptoms vary depending on location of ectopic endometrial tissue
  • Colon – pain when passing stools, abdominal bloating, diarrhoea/constipation during menses, rectal bleeding during menses
  • Bladder – dysuria, haematuria, suprapubic/ pelvic pain, urinary frequency and/or urge incontinence
  • Ovaries – endometrioma formation → rupture/ leakage causes acute abdominal pain
  • Adnexal structures – adhesions resulting in pain or a pelvic mass
• N/b: pain experienced does not correlate with disease severity

Investigations

• Diagnosis only possible by laparoscopy

Management

• Analgesia (analgesic ladder)
• COCP to limit oestrogen production, which encourages proliferation and shedding of endometrial tissue
• Progestogens (IUS, contraceptive injection, contraceptive implant) when COCP not suitable
• Laparoscopic surgical removal of ectopic endometrial tissue
• Hysterectomy (last resort – symptoms can sometimes return)

Complications

• Scarring
• Adhesions (can result in bowel and/or ureter obstruction)
• Pelvic cysts (can rupture)
• Endometrioma
• Thoracic endometriosis (associated with recurrent pneumothoraces)
• Complications in pregnancy