About Anal Fissure

An anal fissure is a small tear or cut in the lining of the anal canal, often caused by the passage of hard or large stools. This painful condition results in sharp pain during bowel movements and may be accompanied by bleeding. Although common and usually benign, if left untreated, fissures can become chronic, causing persistent discomfort and complications.

Anal fissures can affect individuals of any age, but they are particularly common among infants, adults with constipation, and postpartum women. Fissures are classified as acute (healing within 6 weeks) or chronic (lasting beyond 6 weeks). Chronic fissures may involve exposed internal sphincter muscle fibers and often require medical or surgical intervention for relief.

Anal Fissure : Signs and Symptoms

• Sharp, stinging pain during or after bowel movements
• Bright red blood on toilet paper or in stool
• Visible tear near the anus
• Itching or irritation around the anal area
• A small lump or skin tag near the fissure (in chronic cases)
• Spasm or tightness of the anal sphincter
• Avoidance of bowel movements due to fear of pain

Causes of Anal Fissure

Constipation and Hard Stools:

Mechanism: Straining to pass large, hard stools puts pressure on the anal canal lining.
Process: The forceful stretching causes tearing of the delicate mucosa, especially at the posterior midline of the anus.

Chronic Diarrhea:

Mechanism: Frequent loose stools and wiping can irritate and weaken the anal lining.
Process: Repeated irritation disrupts the tissue's ability to heal, resulting in fissure formation.

Childbirth and Trauma:

Mechanism: Vaginal delivery can cause trauma to the perianal region.
Process: Tears may extend to the anal mucosa, especially in women with pre-existing constipation.

Anal Intercourse or Instrumentation:

Mechanism: Insertion of foreign objects or sexual activity may stretch or injure the anal lining.
Process: This direct trauma leads to acute tearing and pain.

Underlying Medical Conditions:

Examples: Crohn’s disease, HIV, tuberculosis, or syphilis.
Mechanism: These conditions impair blood supply and mucosal healing, increasing fissure risk.

Anal Fissure Risk Factors

• Chronic constipation or straining
• Low-fiber diet
• Sedentary lifestyle
• Dehydration
• Recent childbirth (especially vaginal delivery)
• Inflammatory bowel diseases
• Previous anal surgery or trauma
• Immunosuppressive conditions (e.g., HIV/AIDS)

Complications of Anal Fissure

• Chronic Fissure: Failure to heal leads to persistent symptoms beyond 6 weeks.
• Sentinel Pile: A skin tag that forms at the fissure site in chronic cases.
• Anal Spasm: Tightening of the internal anal sphincter that delays healing.
• Infection or Abscess: Rarely, fissures may become infected, leading to perianal abscesses.
• Anal Fistula (Rare): A tunnel from the anal canal to the skin surface may form if infection spreads.
• Bleeding or Anemia (Rare): Chronic bleeding may lead to iron-deficiency anemia in severe cases.
   

Anal Fissure Diagnosis

Physical Examination

Doctors usually identify fissures through visual inspection. A gentle separation of the buttocks may reveal a tear, most often located in the posterior midline. Due to pain, digital rectal examination may be deferred or done under anesthesia in chronic cases.

Anoscopy

A small tube is used to visualize the anal canal. Helps confirm the diagnosis, assess fissure depth, and rule out other anorectal conditions like hemorrhoids or tumors.

Additional Tests (if needed):

• Colonoscopy or Sigmoidoscopy: Recommended if fissures are atypical, recurrent, or located off the midline, raising suspicion for Crohn’s disease or malignancy.
• Biopsy: Rarely needed, unless the fissure is chronic, unresponsive to treatment, or suspected to be linked to systemic disease.

Treatment for Anal Fissure

Anal fissure treatment depends on whether the fissure is acute or chronic. Most acute fissures heal with conservative management, while chronic fissures may require medications or minor surgery.

Non-Surgical Treatments:

Dietary and Lifestyle Changes:

• Increase fiber intake (fruits, vegetables, whole grains)
• Drink plenty of fluids
• Avoid straining and prolonged sitting on the toilet
• Warm sitz baths 2–3 times daily to relax the anal muscles

Medications:

• Topical Nitroglycerin or Calcium Channel Blockers: Relax the sphincter to improve blood flow and promote healing
• Stool Softeners: Prevent straining by making bowel movements easier
• Topical Anesthetics (e.g., lidocaine): Provide pain relief
• Botulinum Toxin (Botox) Injections: Temporarily paralyze the internal sphincter to reduce spasms in chronic cases

Surgical Treatments (for Chronic/Refractory Fissures):

• Lateral Internal Sphincterotomy : A small incision is made in the internal anal sphincter muscle to reduce pressure, promote blood flow, and allow healing. This is the gold standard for chronic anal fissures.
• Fissurectomy : Surgical removal of chronic fissure and associated scar tissue. Occasionally combined with sphincterotomy.
• Advancement Flap Surgery (Rare) : A tissue flap is used to cover the fissure in cases where healing is impaired due to poor blood supply or underlying disease.