Anal Fissure

An anal fissure is a small tear in the mucosa lining the anus. It is usually located in the posterior midline, but in women it may occur in the anterior midline due to anatomical differences. It can occur at any age and affects men and women equally. Fissures may be acute, when they appear suddenly, or chronic, when they persist or recur over time.

The main cause of anal fissures is trauma during defaecation, commonly associated with constipation and hard, bulky stools. Recurrent episodes of diarrhoea or inflammatory processes in the anorectal region may also lead to fissures. Less common causes include rectal cancer, Crohn’s disease, leukaemia and bacterial or viral infections.

Chronic fissures may result from spasm of the internal anal sphincter, which prevents healing by separating the wound edges and reducing local blood flow.

Typical symptoms include severe pain during and after bowel movements, bright red rectal bleeding, anal itching and occasionally foul-smelling discharge. Intense pain may cause patients to avoid defaecation, worsening constipation and perpetuating the fissure.

Diagnosis of anal fissure

• Based on clinical history, symptoms and examination of the anal region;
• Fissures outside the midline or persistent cases may require further assessment under general anaesthesia.

Treatment of anal fissure

Medical treatment

• Regulation of bowel habits with a high-fibre diet and adequate fluid intake;
• Relaxation of the anal sphincter using sitz baths or specific medications;
• Pain relief with analgesics or topical creams;
• Injection of growth factors or botulinum toxin (Botox) to promote healing.

Surgical treatment

• Indicated when medical treatment is insufficient or in recurrent fissures;
• Consists of lateral internal sphincterotomy, a controlled incision of the internal anal sphincter muscle, reducing spasm and allowing healing without compromising sphincter function;
• Complete healing usually occurs within 3 to 4 weeks, with pain relief in the first few days.

Prevention includes maintaining soft, well-formed stools, adequate hydration, a fibre-rich diet, warm sitz baths, good hygiene and prompt treatment of constipation or diarrhoea.