Anal Fissure
💡 Anal fissure is a common but very painful condition caused by a small tear in the mucosal lining of the anal canal. Although benign, it can have a major impact on quality of life due to severe pain during and after defaecation.
📘 About
- Small linear tear in the anoderm (anal canal mucosa).
- Classically located posteriorly in the midline.
- May be acute (heals within weeks) or chronic (persists >6 weeks with fibrosis or sentinel skin tag).
🧬 Aetiology
- 💥 Localised trauma: Most often from passage of large, hard stool (constipation).
- 🔄 Other causes: Insertion of foreign objects, sexual trauma, childbirth, inflammatory bowel disease (especially Crohn’s), chronic diarrhoea.
⚠️ Clinical Features
- 🔥 Severe pain on defaecation: Often described as “like passing broken glass.”
- ⌛ Persistent pain: Lasts minutes to hours afterwards, sometimes worse than expected for such a small lesion.
- 📍 Typical site: Posterior midline; anterior fissures are less common (consider Crohn’s if multiple or lateral).
- ❌ Exam tolerance: Patients may be unable to tolerate digital rectal exam due to pain.
- 💧 Bright red rectal bleeding often noted on toilet paper.
🧪 Investigations
- Primarily a clinical diagnosis.
- 🔬 Bloods (FBC, U&E, LFTs) if dehydration, anaemia, or systemic disease suspected.
- 📑 Examination under anaesthesia (EUA) with proctoscopy if pain prevents full exam or to exclude haemorrhoids / malignancy.
💊 Management
- 🥦 Lifestyle: High-fibre diet, hydration, stool softeners (e.g. Lactulose, Movicol) to reduce straining.
- 💊 Pain relief: Simple analgesia; warm sitz baths may soothe discomfort.
- 🧴 Topical agents:
- Glyceryl trinitrate (GTN) ointment – relaxes internal sphincter, increases blood flow; applied twice daily for up to 8 weeks (common SE = headache).
- Diltiazem 2% cream – calcium channel blocker alternative with fewer headaches.
- 💉 Botulinum toxin injection: Into the internal sphincter; useful if medical therapy fails.
- 🔪 Surgery: Lateral internal sphincterotomy (LIS) for chronic/refractory fissures – high success but risk of incontinence must be considered.
📚 References
