An anal fistula is an abnormal tunnel that forms in the anal canal and runs through an external opening on the skin around the anus (perianal skin).
Causes of Anal Fistula
Humans have fluid-secreting glands inside the anus that can sometimes get clogged or blocked. When this happens, bacteria start to build up and create a swollen pocket of infected tissue and liquid called an abscess. If not treated, this abscess will eventually form a tunnel and punch a hole in the perianal skin to allow the abscess to drain.
Inflammatory bowel disease (Crohn’s disease), diverticulitis, tuberculosis, trauma, cancer (including treatments like radiation therapy) can increase the risk of developing an anal fistula.
Symptoms of Anal Fistula
The symptoms of anal fistula include:
- Pain in the anal area that grow worse when sitting down or during a bowel movement
- Redness and swelling in the anal area
- Skin irritation and itching around the anal and perianal area
- Bloody or foul-smelling discharge from an opening in the anal area
- Pus or abscess drainage in the perianal skin
How an Anal Fistula is Diagnosed
Immediate medical attention should be sought if two or more symptoms above are present. During such appointments, the doctor will first review the patient’s medical history and assess the symptoms through a visual and physical exam, which is usually enough to diagnose an anal fistula.
In some cases, the doctor may conduct other diagnostic tests such as:
- Anoscopy – This is a procedure in which a thin and flexible camera-equipped instrument is inserted into the anus to better visualise the inside of the anus and rectum.
- Imaging Studies – Ultrasounds and MRIs may be done to determine the location, size and severity of an anal fistula.
- Fistula Probe – This test involves inserting a long, thin probe through the anal fistula. A special dye may also be used to accurately locate where the fistula opens up inside the anus.
Treatment for Anal Fistula
The only way to effectively treat anal fistula is through surgery. The primary goals of surgery are to drain the abscess and close the fistula, and at the same time protect the anal sphincter muscles and preventing incontinence. Surgical treatments include:
- Seton placement – This involves placing a band (seton) or suture through the fistula, which is progressively tightened, allowing the abscess to drain and the fistula to heal on its own overtime.
- Gluing or plugging – This involves using a special glue or plug to close the fistula. A new technique related to this treatment is filling the entire tunnel with a glue material that will be absorbed by the body overtime.
- Fistulotomy – This procedure involves cutting open the anal fistula, and allowing it to heal naturally.
- Advancement flap procedure – This involves obtaining a piece of tissue from the rectum and using it to seal the opening of the fistula.
- Ligation of intersphincteric fistula tract (LIFT) procedure – This procedure involves cutting open the skin above the anal fistula, spreading the sphincter muscles, and then ligating or tying off the fistula closed.
Managing Anal Fistula
Surgery is enough to address anal fistulas, but patients should still take proper care of themselves at home to facilitate quick recovery. After surgery, doctors may recommend:
- Soaking the anal area in warm water (sitz baths) 3 to 4 times a day
- Covering the affected area with a clean pad
- Using stool softeners or laxatives for a week
- Taking antibiotics, pain relievers and other prescribed medicines
Remember to go back for a follow-up check to ensure that the wound is healing properly as intended.