Anal fistula is the formation of a channel between the end of the large intestine and the skin around the anus or rectum. This condition is caused by an infection that develops into a pus-filled lump (abscess) in the skin area around the anus.
Abscesses near the anus can continue to grow if not treated. Over time, the pus in the abscess will try to find its way out of the body and form a channel under the skin to the anus. This condition is called an anal fistula.
An anal fistula can cause pain and swelling around the anus, as well as a foul-smelling discharge of pus during bowel movements. This condition is more common in men and usually first appears around the age of 40.
Causes of Anal Fistula
Most anal fistulas begin with an anal abscess that is not resolved or does not heal completely. Over time, the buildup of pus in the anal abscess will press on the area around it and seek a way out. As a result, a channel is formed from the abscess to the anus or rectum called an anal fistula.
There are several conditions that can increase a person's risk for an anal fistula, namely:
- Crohn's disease
- Diverticulitis
- Anal fissure
- Sexually transmitted diseases, including lymphogranuloma venereum (LGV)
- Carcinoma or malignancy of the colon
- Fungal infections, such as actinomycosis
- Bacterial infections, such as tuberculosis
- Diabetes mellitus
- Injury to the anus
- Radiation therapy
- Complications of surgery in the area around the anus
Symptoms of Anal Fistula
Here are a number of symptoms that can appear due to an anal fistula:
- Pain in the anal area that gets worse when sitting, moving, defecating, or coughing
- Irritation of the skin around the anus, such as swelling, changes in skin color to redness, and itching
- Bleeding when defecating
- Discharge of foul-smelling pus from the skin near the anal opening
- Fever, chills, and feeling tired
- Difficulty controlling the passage of feces
When to go to the doctor
See a doctor immediately if you experience any of the symptoms listed above, especially if you've had an anal fistula before, as this condition may come back. It is important to treat the condition as early as possible and prevent complications.
People who have an anal abscess, have a sexually transmitted disease, and Crohn's disease are more likely to develop an anal fistula. Therefore, if you experience these diseases or conditions, check with your doctor to monitor your condition and take steps to prevent the emergence of anal fistulas.
Anal fistula diagnosis
To diagnose anal fistula, the doctor will ask about the symptoms experienced and the patient's medical history. After that, the doctor will perform a physical examination of the anus and the area around it.
The doctor will check for signs of irritation in the anus and the surrounding area, see if there is a small hole near the anal opening that oozes pus when pressed, and perform a digital rectal examination to confirm an anal fistula.
Some fistulas can be detected only through physical examination, but others do not show signs on the skin surface and require further examination.
The following are some of the types of investigations needed to confirm the diagnosis of anal fistula:
- Proctoscopy, which is an examination with a special instrument with a light at the end, to see conditions inside the anus
- Fistula probe, namely examination with special tools and dyes, to determine the location of the fistula tract and abscess
- Anoscopy, which is an examination with a special instrument in the form of an anal speculum, to see conditions inside the anal canal
- Colonoscopy, which is an examination with a camera tube inserted through the anus to see the condition of the large intestine and the cause of anal fistula
Anal Fistula Treatment
Anal fistula treatment aims to remove pus and eliminate the fistula while protecting the anal sphincter muscle (the muscle that controls the opening and closing of the anus).
Anal fistula treatment will be done with surgery. Several types of surgery to treat anal fistulas are:
1. Fistulotomy
This surgical step is chosen if the location of the anal fistula is not or only slightly associated with the sphincter muscle. Fistulotomy is done by opening the skin and muscles of the anal fistula tract, cleaning the area, and leaving it open so that natural healing occurs from within.
2. Blockage of the fistula
This procedure is performed after the pus has been drained. In this procedure, the fistula tract will be plugged with a special material that can be absorbed by the body, until finally closing the fistula.
3. Seton installation
In this procedure, a thread-like material (seton) is threaded through the opening of the fistula to form a knot so that the fistula tract is widened and the pus from the abscess is drained.
The level of tension of the thread will be adjusted by the doctor to close the fistula channel during the recovery period. When the channel is closed, the thread will be removed. Generally, seton thread is installed for 6 weeks.
4. Network installation (advancement flap procedure)
This procedure may be selected if the fistula passes through the sphincter muscle. In this procedure, the fistula tract will be dissected, cleaned, and then patched with tissue taken from the rectum because of its sphincter-like nature.
The rectum is the final part of the large intestine that serves as a temporary storage place for feces before being expelled through the anus.
5. Binding of the fistula tract or LIFT . procedure
LIFT procedure (ligation of the intersphincteric fistula tract) may be selected if the fistula passes through the sphincter muscle. This procedure involves making an incision over the fistula, removing the inflamed center and then tying and suturing the ends so that the canal is closed.
After surgery, doctors will generally prescribe pain medication and antibiotics to manage pain and prevent postoperative infection. In addition, the patient may also need to make regular visits to the doctor to make sure the anal fistula is completely healed.
Postoperative care
To speed up the healing process, the doctor will advise the patient to self-treat the postoperative wound. Recommended treatments include:
- Soak in warm water 3-4 times a day
- Wearing pads on the anal area during wound healing
- Increase fiber-rich foods and drink water to prevent constipation
- Taking laxatives to soften stools if needed
Patients can return to normal activities after being declared cured by the doctor.
Complications of Anal Fistula
Some of the complications that may occur due to an anal fistula or surgery are:
- Fecal incontinence
- Recurrence of anal fistula
- Anal stenosis (narrowing of the anus)
Anal Fistula Prevention
There are several ways that can be done to reduce the risk of anal fistula formation, namely:
- Maintain the cleanliness of the genitals, anus, and the surrounding area
- Do not change partners in having sex
- Implement a healthy and balanced diet, and drink adequate amounts of water
- Take regular medication and check with the doctor if you suffer from diseases that can increase the risk of anal fistula