Anal Fistula

1 What is Anal Fistula?

Anal fistula refers to an infected cavity that develops between the skin and the anus.

Most of the fistulas are formed from an infection of one of the anal glands. It is caused by incomplete healing of a drained anal abscess.

The drainage may be spontaneous or through surgery. Anal fistulas can be classified as simple or complex based on the number of fistulas and the presence of interlink between them.

It is also grouped into low or high, based on the location of the fistula. Fistulas cause anorectal pain and swelling in the region.

Diagnosis is based on symptoms and physical examination.

Surgical drainage is the most common treatment option for anal fistula. 

2 Symptoms

Some of the common signs and symptoms of anal fistula are

  • Anorectal pain
  • Swelling
  • Redness of skin in and around anus
  • Fever
  • Bleeding
  • Pus discharge from the opening of fistula
  • Skin irritation due to discharge
  • Fatigue 

In some cases, anal fistula may affect urination resulting in painful urination or difficulty in initiating a urinary stream.

Pain is persistent and usually worsens while sitting.

3 Causes

The main cause of anal fistula is the drained abscess that is not healed completely.

Fistulas may also form after the bursting of an anal abscess.

Gastrointestinal diseases like inflammatory bowel disease and diverticulitis cause anal fistulas.

It is very often associated with Crohn’s disease, HIV infection, and anal abscesses. 

4 Making a Diagnosis

Making a diagnosis of anal fistula is done by physical examination of the perianal region.

The depth and direction of fistula are assessed from the external opening of fistula. If the opening of fistula is not visible from outside, additional tests are recommended.

Anoscopy is a procedure in which a short tube called anoscope is introduced into the anal canal to visualize the internal tissues.

Images produced by MRI and ultrasound scan helps to obtain a better picture of the anal canal and the surrounding regions.

If the fistula is complicated or is located in an unusual place, other tests are used to track the fistula. This includes fistulography, a procedure in which sodium is injected into the fistula and an image taken by X-ray. Diluted methylene blue dye is also used for injection to trace the path of fistula in the anal canal.

Further tests are based on the cause of the disease. Flexible sigmoidoscopy helps to visualize the lining of rectum and colon to rule out abnormalities like Crohn’s disease or ulcerative colitis. Colonoscopy is used to examine the entire colon.

5 Treatment

Location and complexity of anal fistula are the two deciding factors for treatment.

Care is taken to protect the anal sphincters so as to not affect the bowel movement.

Some of the common methods used in the treatment include

  • Fistulotomy – in this procedure the internal opening of the fistula is opened to drain the infected tissue. The cavity is then removed by stitching the canal. In case of complicated fistula, a small portion of the channel is removed.
  • Rectal flap – a small flap is made from the internal opening of the fistula. This rectal flap is used to cover the cavity. This prevents the removal of anal sphincter.
  • Seton – in this procedure, the fistula is drained with the help of a silk or latex string, called seton.
  • Fibrin glue – The channel is drained and the internal opening of fistula shut. Fibrin glue is used to plug the external opening of fistula. The fistula is also plugged with a collagen protein.
  • Ligation of the intersphincteric fistula tract – this procedure is used for complicated fistulas without cutting the anal sphincter. A seton is placed in the tract of fistula and after few weeks the infected tissue is removed. The internal opening of the fistula is then sealed completely. 

When the fistula is complex, a temporary opening is created in the abdomen to remove waste. This promotes healing of the anal area. In very complex forms the channel of fistula is filled with muscle tissue taken from other parts of the body like thigh.

6 Prevention

Treating anal abscesses and allowing complete healing of the anal area helps to prevent formation of anal fistula.

Treating the medical conditions that increase the risk of anal fistulas is also a definitive preventive measure for anal fistulas. 

7 Alternative and Homeopathic Remedies

There are several alternative and homeopathic remedies used for anal fistula.

Diet plays a very important role in the treatment of anal fistula.

Diet rich in fiber is recommended.

  • Amla,
  • Terminalia chebula,
  • commiphora mukul,
  • curcumin,
  • and neem

are some of the herbal remedies considered to be useful in the treatment of anal fistula.

  • Myrista sebifera,
  • causticum,
  • paeonia,
  • hydrastis,
  • nitric acid,
  • and lachaesis

are used in homeopathy to relieve the symptoms of fistula. 

8 Lifestyle and Coping

There are different ways to adapt your lifestyle in coping with anal fistula.

Pain killers help to reduce pain associated with surgery.

Patients should have a diet rich in fiber and have adequate water to soften the stool and avoid constipation.

Sitz bath are very effective in reducing pain and to promote healing. 

9 Risk and Complications

There are several common factors that increase the risk and affect complications of anal fistula.

Fistula surgery may lead to infection, particularly if the fistula is not completely removed.

This infection can spread to other parts of the body.

If the anal sphincter is damaged during surgery, it leads to bowel incontinence.

Recurrence of fistulas is another probable complication of this condition.