Anal Fistula
An anal fistula is a tunnel between the anal canal and nearby skin, often following an abscess. It does not usually heal on its own. Specialist assessment helps define its route and plan treatment while protecting bowel control; it is not the same condition as a pilonidal sinus.
In this guide
Overview
An anal fistula is a small tunnel that develops between the skin near the anus and the inside of the anal canal. It usually occurs due to an infection in an anal gland, leading to the formation of a tunnel (fistula) that can cause discomfort and recurrent drainage of pus or fecal matter. Here are some key points to know about anal fistulas:
Causes
- Anal Abscess: Most anal fistulas develop from untreated anal abscesses, where the infection spreads and forms a tunnel between the anal gland and the skin.
- Crohn’s Disease: Inflammatory bowel diseases like Crohn’s disease can increase the risk of developing anal fistulas.
Symptoms
- Pain and Discomfort: Patients may experience pain, swelling, and tenderness around the anus, especially during bowel movements.
- Perianal Discharges: Pus, blood, or foul-smelling discharge may come from an opening near the anus, causing itching and irritation.
Diagnosis
- Physical Examination: A doctor will perform a physical examination of the anal area to look for signs of a fistula.
- Imaging Tests: Imaging studies such as MRI or ultrasound may be used to visualize the fistula tract and determine its path.
Treatment
- Surgical Intervention: The primary treatment for an anal fistula is surgery to remove the tract and promote healing. Various surgical techniques may be used depending on the complexity and location of the fistula.
- Seton Placement: In some cases, a seton (a piece of thread-like material) may be placed through the fistula to facilitate drainage and prevent infection before definitive surgery.
- Medication: Antibiotics and pain medications may be prescribed to manage symptoms and prevent infection.
Prevention
- Prompt Treatment of Anal Abscesses: Treating anal abscesses early can help prevent the formation of anal fistulas.
- Good Anal Hygiene: Keeping the anal area clean and dry can help prevent infections that lead to fistulas.
In conclusion, anal fistulas are a common condition that requires prompt diagnosis and appropriate treatment to prevent complications and promote healing. Consulting a healthcare provider for evaluation and management is essential for individuals experiencing symptoms of an anal fistula.
A little more clarity
Your questions, answered
Can a fistula remain after an abscess has been treated?
Yes. A tunnel can remain after an anal abscess has drained or been treated. Recurrent swelling or discharge near the anus should be assessed. A fistula does not necessarily mean that the abscess was ignored or that previous treatment was wrong.
Why might I need an MRI scan or an examination under anaesthetic?
The team may need to establish where the fistula runs, whether it branches and how it relates to the muscles that control the anus. Imaging or an examination under anaesthetic can help plan treatment. Not everyone needs the same investigations.
Does a draining seton mean the fistula has been cured?
Not necessarily. A loose seton is a surgical thread used to keep a fistula open and allow drainage. It may be part of a staged plan rather than the final treatment. Ask what type of seton is proposed, its purpose and what review or further treatment is expected.
Why is bowel control important when choosing fistula surgery?
Some fistulas pass through the anal sphincter muscles, which help control wind and stool. Opening the whole tract may not be suitable if it would damage too much muscle. The surgeon should discuss healing, recurrence and bowel control risks when comparing treatment options.
Can an anal fistula be related to Crohn's disease?
Yes, some fistulas are associated with Crohn's disease, although many follow an anal gland infection. Tell your clinician about any known bowel disease or ongoing bowel symptoms. Where Crohn's disease is involved, medical and surgical care may need to be coordinated rather than treating the fistula in isolation.
Sources & further reading
This guide provides general information, not an individual diagnosis or treatment plan. Your clinical team will advise what is appropriate for you.