Chronic Anal Fissure

A chronic anal fissure persists beyond the normal acute healing period and develops structural changes including a sentinel skin tag, hypertrophied anal papilla and exposed internal sphincter fibres.

Persistent internal anal sphincter hypertonicity reduces anodermal perfusion and prevents healing.

Maintain soft formed stool using fibre and polyethylene glycol when needed.

First line pharmacological sphincter relaxation can use:

Diltiazem 2% topical cream applied to the anal verge twice daily for approximately 6 to 8 weeks.

An alternative is:

Glyceryl trinitrate 0.2% to 0.4% ointment applied twice daily for approximately 6 to 8 weeks. Diltiazem provides similar healing with fewer headaches than topical nitrates.

Botulinum toxin is useful after topical treatment failure or when avoiding sphincter division is important.

A commonly used total dose is:

Botulinum toxin 20 to 60 units injected into the internal anal sphincter, divided between one or more sites. There is no single superior injection protocol.

Lateral internal sphincterotomy provides the highest healing rate and is appropriate for chronic primary fissure that persists despite medical treatment or in selected patients where definitive surgery is preferred. Divide only enough internal sphincter to reach approximately the proximal extent of the fissure rather than automatically dividing to the dentate line. Tailored sphincterotomy reduces unnecessary sphincter injury.

Avoid or use major caution with sphincterotomy in patients with baseline faecal incontinence, previous obstetric sphincter injury, inflammatory bowel disease or previous sphincter dividing anorectal surgery.

In these patients, fissurectomy with an advancement flap or botulinum toxin can preserve sphincter function. Healing after lateral internal sphincterotomy is approximately 88% to 100%, but continence risk must be considered individually.

Ischaemic Colitis

Ischaemic colitis results from transient or sustained reduction in colonic blood flow. Most disease is nonocclusive and affects watershed regions, particularly the splenic flexure and rectosigmoid junction.

Severity ranges from reversible mucosal injury to transmural gangrene.

Isolated right sided disease is clinically important because it is associated with more severe outcomes and may indicate proximal mesenteric arterial disease.

Mild disease is treated with bowel rest, IV fluid correction, optimisation of cardiac output and withdrawal of precipitating vasoconstrictive drugs where possible.

Avoid hypotension because repeated low flow insults can convert reversible injury into infarction.

Moderate or severe disease should receive broad enteric antimicrobial coverage, for example:

Ceftriaxone 2 g IV every 24 hours plus metronidazole 500 mg IV every 12 hours.

Urgent surgery is required for:

Peritoneal signs
Gangrene
Perforation
Persistent clinical deterioration
Uncontrolled sepsis
Massive bleeding
Extensive right sided or pancolonic necrosis.

Resect nonviable colon. Avoid primary anastomosis when perfusion of remaining bowel is uncertain or the patient is physiologically unstable.

A healed ischaemic segment can later form a fixed symptomatic stricture. Persistent obstructive symptoms require elective segmental resection.

Chronic Anal Fissure

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management