A perianal fistula is a medical term used to name a small cavity or tunnel-shaped wound, usually caused by an anorectal abscess. This type of injury is located from the inside of the rectum to the skin around the anus. It usually appears as a result of an infection that begins in the anal gland, forming the abscess (accumulation of pus under the skin) that drains spontaneously or by surgical methods. The abscess can also form from an anal fissure (or break in the lining of the anus). And once the pus has drained, the cavity that connects the anal gland with the skin near the anus forms.
It is a common disease among adults and in those children who suffer from inflammatory bowel disorders such as Crohn’s disease.
What are the symptoms of a perianal fistula?
A perianal fistula can have one or more holes that can commonly be seen with the naked eye. Pus or fecal matter is expelled from them, sometimes with traces of blood, causing irritation of the skin around the anus, causing pain, redness, inflammation and itching.
The pain of this injury can increase when sitting, defecating, sneezing or coughing, with an intensity that varies according to the pressure with which these actions are carried out.
The most common symptoms of the appearance of a perianal fistula (for which the doctor is usually consulted) are:
- Severe pain in the perianal area (between the anus and the rectum) when sitting, defecating, sneezing or coughing.
- Discharges of pus, fecal and bloody matter.
- A hard, reddish lump, with the skin taut, hot and painful to the touch, characteristic of the abscess that causes this type of injury.
- Painful bowel movements due to inflammation.
- General malaise, fever, chills, muscle and joint pain from infection.
What causes a perianal fistula?
It occurs because once pus accumulates inside a cavity, it will end up draining it until it forms a kind of conduit or tunnel. That is the most likely cause of the fistula formation. The risk factors that predispose to the formation of the perianal fistula are the following:
- An infection or inflammation, an injury (even that generated by a previous surgery) or the obstruction of the anal gland.
- The infection of an anal fissure, that is, of the rupture of the anal mucosa.
- A sexually transmitted infection.
- Crohn’s disease, ulcerative colitis, diverticulitis or other intestinal disorders that cause inflammation of the anorectal area.
- Radiotherapy treatments of perianal tissues or close to this area.
- Anorectal cancer.
- Use of corticosteroids.
- Weakness of the immune system.
- Trauma from anal sex or foreign bodies.
How do you make the diagnostic?
Once in the consultation, the doctor will perform a physical examination, to look for the presence of holes, openings or abscesses that will indicate if you are in the presence of a perianal fistula. The lesion may not be on the surface. Therefore, a digital rectal examination will be performed to determine the length and other characteristics of the perianal fistula path. You can also use a special instrument (anoscope) to look inside the fistula, take samples, and make an accurate diagnosis.
In the diagnosis phase, the aim is to determine what has caused the appearance of the fistula, that is, the underlying pathology (Crohn’s disease, ulcers, diverticulitis, cancer, etc.). For this reason, the rectal examination will be accompanied by other tests indicated by the doctor, such as anal or endoanal ultrasound, sigmoidoscopy (observation of the large intestine), magnetic resonance imaging, tomography, among others.
How is a perianal fistula cured?
When the perianal fistula is caused by Crohn’s disease, the lesion is treated with antibiotics, immunosuppressants, anti-inflammatories, analgesics, or medications prescribed by the doctor. Sufficient hydration and fiber consumption in the daily diet is also recommended. In this case, surgical intervention becomes the last option.
The palliative treatment of the discomfort caused by perianal fistulas can be the same as that used to treat hemorrhoids, although it will depend on the severity of the injury.
The only treatment capable of completely eliminating a perianal fistula is surgical intervention. Once the fistula disappears, the discomfort it generated also disappears: pain, secretions, inflammation, bleeding, etc.
What are the risks of having surgery?
The risks or complications that could occur after surgery to remove a perianal fistula are:
- Some patients may experience bleeding from the wound, swelling, pain, and retention of urine.
- That the fistula reappear after surgery. Therefore, the patient must undergo a new surgical intervention to eliminate it.
- On some occasions the patient may have difficulties urinating, unlike how he did before the intervention.
- The patient can get a urinary infection.
- If you suffer from Crohn’s disease, healing may take longer postoperative time.
- Although rare, major complications can occur after surgery. For example, the occurrence of severe infections in the intervened area, stenosis (reduction of the anal canal) or that the patient acquires anal incontinence (both gas and stool). This complication is also associated with the patient’s previous illnesses and the surgeon’s practice.
Following the instructions of your trusted doctor is very important to prevent the reappearance of the injury. Therefore, the precise diagnosis of the injury, together with the appropriate selection of the surgical intervention technique to be performed, must be followed by strict compliance with the treatment ordered by your doctor. In this way, the perianal fistula will close completely and will not reappear.
How to prevent perianal fistulas?
- Follow a balanced diet, rich in fiber, fruits, vegetables and light in animal fats (that your portion is full of natural colors). This way you will avoid constipation and strengthen your immune system.
- Avoid refined foods.
- Hydrate daily.
- Maintain the hygiene of the anorectal area.
- Avoid sedentary life: Do moderate exercise regularly.