In this article, we cover common benign anorectal pathologies including haemorrhoids, fissures & fistulas with a quick overview of their assessment & management.
Contents
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Basic anatomy
- Anatomical position of anus is described by a clock in the lithotomy position (lying on back with legs apart, pubic symphysis is 12 o’clock, coccyx is 6 o’clock)
- Internal anal sphincter – surrounds upper 2/3rds of anal canal. Involuntary. Smooth muscle.
- External anal sphincter – surronds lower 2/3rds of anal canal. Voluntary. Skeletal muscle
- Pectinate line
Haemorrhoids (Piles)
- What is it?
- Swollen vein in lower rectum
- How does it present?
- Painless PR bleeding in bowl/on wiping. Itching.
- Pain if thrombosed
- Risk factors
- Heavy lifting, prolonged sitting, obesity, constipation, pregnancy
- Diagnosis
- PR examination (typically impalpable but occasionally visible), proctoscopy
- Treatment
- Conservative: sitz bath, dietary fibre, hydration
- Medical: Anusol, stool softners, (topical GTN if thrombosed)
- Surgical: Haemorroidectomy (thrombectomy). Band ligation/sclerotherapy
Fissure in Ano (Anal Fissures)
- What is it?
- A mucocutaneous defect of the anal canal (a tear)
- How does it present?
- Painful PR bleeding (why is it painful?)
- Risk factors
- Mostly idiopathic (90%)
- Constipation, Crohn’s, tuberculosis
- Diagnosis?
- PR examination (90% posterior midline), EUA
- Management?
- Conservative – stool softners, fibre, hydration
- Medical – topical GTN (0.2%) or diltiazem (2%). Botulinum toxin injection.
- Surgical – lateral sphincterotomy (10% incontinence to flatus) , advancement flaps
Fistula in Ano (Anal Fistulas)
- What is it?
- Abnormal connection between two epithelial surfaces (rectum+skin with 2x openings)
- How does it present?
- A discharging hole -> sepsis
- Risk factors
- Crohn’s, tuberculosis, diabetes, HIV
- Diagnosis?
- PR examination
- EUA, MRI
- Goodsall’s rule
- Within 3cm of the anus, anterior openings will follow a straight line into the anal canal, which posterior openings will curve towards the midline and then enter the
- Of clinical importance when trying to find the internal openings during surgery (via PR and using a Lockhart-mummery probe)
- Management
- Abscess -> I&D (secondary intention) +/- sepsis 6
- Fistula usually once infection resolves (if it was present):
- Fibrin glue (50% failure)
- Seton
- Fistulotomy “lay open” (CI: Crohn’s, high tract)
- Complex surgery (advancement flaps)
Written by Dr Marc Huttman (FY2)
