Anal fissures are small tears in the lining of the anal canal. They tend to form due to the stretching and tearing of the lining of the anus, which can occur due to the passing of large, hard stools or severe bouts of diarrhoea. Anal fissures often cause pain and bleeding with bowel movements.
Anal fissures are very common and can affect people of any age. Usually, they only require simple treatments such as topical ointments or increased fibre intake. Only in certain conditions will surgery be recommended by your doctor.
Causes of anal fissures
Fissures are caused by trauma to the lining of the anus from a bowel movement or other stretching of the anal canal. This can be due to a hard, dry bowel movement or loose, frequent bowel movements. Patients with a tight anal sphincter muscle are more likely to develop anal fissures. Less common causes of fissures include inflammatory bowel disease.
Anal fissures typically cause a sharp pain that starts with the passage of stool. This pain may last several minutes to a few hours. As a result, many patients may try not to have bowel movements to prevent pain.
Other symptoms include:
- Bright red blood on the stool or toilet paper after a bowel movement
- A small lump or skin tag on the skin near the anal fissure (often mistaken as a haemorrhoid)
Anal fissures are often misdiagnosed as haemorrhoids because both conditions cause bleeding and pain. However, the overriding symptom for anal fissures is severe pain with some bleeding. The overriding symptom for haemorrhoids is a lump at the anus with bleeding usually without much pain. A thorough examination by an experienced doctor will usually be able to differentiate one condition from another.
Treatment of Anal fissures
Patients with anal fissures get caught in a vicious cycle of a recurring anal tear resulting in chronic anal pain, which leads to chronic anal spasm and increased anal tone. This results chronic constipation which leads to large hard stools during defecation which causes the recurring anal tear. (Tear/pain/spasm/constipation cycle)
Anal fissures are treated with medication and this has an 80% to 90% chance of successful treatment. The aim of medical treatment to the break the cycle. Pain is treated with painkillers. Anal spasm is treated with Rectogesic ointment and constipation with laxatives. The tear will usually heal with such treatments. Failure to recover despite medical treatment is an indication for surgery (10% to 20%)
Surgical Treatment (Lateral internal sphincterotomy)
Although most anal fissures do not require surgery, chronic fissures are harder to treat and surgery is the best option. Surgical division of an inner part of the anal sphincter (lateral internal sphincterotomy) is the Gold standard for chronic anal fissures. The aim of surgery is to help the anal sphincter muscle relax which reduces pain and spasms, allowing the fissure to heal. This is usually done as a day surgery procedure.
Alternatives to Surgery
Botulinum toxin (Botox®) injection into the anal sphincter causes temporary muscle weakness to the internal sphincter and hence relaxes the muscle tone. As this is temporary, it can be repeated though its effectiveness is reduced with each repeated dose.
Most patients can return to work and go back to daily activities a few days after surgery. Complete healing after both medical and surgical treatments take 6 to 8 weeks. Even when the pain and bleeding lessen, it is important to maintain good bowel habits and eat a high-fibre diet. Continued hard or loose bowel movements, scarring, or spasm of the internal anal muscle can delay healing.
- Botox® injections are associated with healing of chronic anal fissures in 50% of patients.
- Sphincterotomy is successful in more than 90% of patients. Less than 1% of patients have a risk of faecal incontinence.
Anal fissures often come back. A fully healed fissure can come back after a hard bowel movement or trauma. Anal fissures do not increase the risk of colon cancer nor cause it. However, more serious conditions can cause similar symptoms. Even when a fissure has healed completely, your surgeon may request other tests. A colonoscopy may be done to rule out other causes of rectal bleeding.