About Anal Fistula

An Anal fistula is an abnormal, narrow tunnel that forms between the end of the bowel (anal canal) and the skin around the anus. It often develops following an infection in an anal gland that leads to an abscess. When the abscess drains or bursts, a tract may remain, forming a fistula. This condition can be painful, irritating, and recurrent if left untreated.

Fistulas are more common in individuals with prior perianal abscesses, Crohn’s disease, tuberculosis, or recent anorectal surgery. While some may present with mild symptoms, others experience continuous discomfort, swelling, or pus discharge. Proper medical evaluation is essential for long-term healing and preventing recurrence.

Signs and Symptoms of Anal Fistula

• Constant or intermittent pus or fluid discharge from an opening near the anus
• Redness, tenderness, or swelling around the anal region
• Recurring pain that worsens during movement, sitting, or defecation
• Fever or chills if an abscess is present
• Irritation or itching due to continuous leakage
• A small, visible opening or hole on the skin around the anus
• Foul-smelling discharge or blood

Causes of Anal Fistula

Perianal Abscess (Most Common):

• Cause: Infected anal glands near the anal canal
• Progression: Once the abscess drains or is surgically treated, a tunnel may remain connecting the anal canal to the skin surface

Crohn’s Disease and Other Inflammatory Bowel Conditions:

• Cause: Inflammation weakens the intestinal wall
• Progression: Leads to tract formation between the bowel and the skin

Tuberculosis and STDs:

• Cause: Infectious agents damage deep tissues
• Progression: May result in chronic fistulas or complex tracts

Radiation Therapy or Surgery:

• Cause: Tissue damage from cancer treatment or surgical trauma
• Progression: Delayed healing or chronic infections can cause fistula development

Trauma or Injury:

• Cause: Direct damage to the anorectal region
• Progression: Leads to tissue breakdown and abnormal tunnel formation

Anal Fistula Risk Factors

• Prior history of anal or perianal abscess
• Chronic inflammatory bowel diseases like Crohn’s or ulcerative colitis
• Immunocompromised conditions (e.g., HIV)
• History of radiation to the pelvic area
• Previous anorectal surgeries
• Poor hygiene or recurrent infections in the anal region
• Tuberculosis or sexually transmitted diseases

Anal Fistula Complications

• Persistent Discharge: Continuous leakage of pus or stool from the external opening
• Recurring Abscesses: Repeated infections due to blocked fistula tracts
• Complex Fistula Formation: Multiple tracts or involvement of deep tissues
• Anal Incontinence (Rare): Possible if sphincter muscles are affected during surgery
• Cellulitis or Systemic Infection: Can occur if infection spreads unchecked
• Impaired Quality of Life: Chronic pain, embarrassment, and discomfort

Anal Fistula Diagnosis

• Clinical Examination: Doctors inspect the area for external openings, discharge, or skin irritation. Gentle palpation may reveal tenderness or a firm tract beneath the skin.
• Digital Rectal Examination : Used to assess internal openings or evaluate the extent of the fistula. May be deferred if pain is severe.

Imaging Tests:

• MRI Fistulogram: Offers detailed images of the fistula’s path and depth
• Endoanal Ultrasound: Helps visualize the tract and its relation to the sphincter muscles
• CT Scan or Colonoscopy (if needed): May be ordered if inflammatory bowel disease or other internal pathology is suspected

Anal Fistula Treatment Options

The management of anal fistulas typically requires surgical intervention, especially if they are chronic or complex. The goal is to eliminate the fistula while preserving sphincter function and minimizing recurrence.

Non-Surgical Measures (Supportive Only)

• Antibiotics: Used if infection or cellulitis is present
• Pain Relievers and Sitz Baths: Help ease discomfort and promote cleanliness
• Seton Placement (Temporary): A surgical thread is placed to keep the fistula open and draining, preventing abscess formation

Surgical Treatments

• Fistulotomy (Standard Treatment): The tract is surgically opened and allowed to heal as a flat scar. This is suitable for simple, superficial fistulas.
• Seton Technique (For Complex Fistulas): A medicated thread is left in place to promote drainage and prevent infection while maintaining sphincter integrity.
• LIFT Procedure (Ligation of Intersphincteric Fistula Tract): The fistula tract is identified and tied off between the muscle layers. Ideal for transsphincteric fistulas.
• Fibrin Glue or Collagen Plug (Minimally Invasive): Biocompatible materials are injected or placed to seal the tract. Suitable for select cases, but recurrence risk exists.
• Advancement Flap Surgery: A flap of healthy tissue is used to cover the internal opening, mostly used in recurrent or non-healing cases.