When to Seek Urgent Care
A painful swelling with fever, chills, spreading redness, difficulty passing urine or feeling very unwell may be an anal abscess and needs urgent drainage assessment. Antibiotics alone do not cure a drainable abscess.
Understanding the Condition
A fistula often starts when an infected anal gland forms an abscess. After the abscess drains, a tunnel can remain and cause repeated swelling, pain, pus or blood from an opening near the anus. The opening may seem to heal and then reopen.
The key question is how much of the anal sphincter muscle the tract crosses. A low simple fistula and a high branching fistula need different operations.
How It Is Assessed
Examination looks for openings, scars, active infection and existing continence. MRI of the pelvis is especially useful for a recurrent, branching or high fistula. Examination under anaesthesia may be needed to map and drain the tract safely.
Bowel symptoms or an unusual pattern may require tests for Crohn's disease, tuberculosis or another cause.
When Is Surgery Considered?
A persistent anal fistula usually needs a procedure because the tract rarely heals permanently on its own. Any abscess is drained first. A loose seton may be placed through the tract to maintain drainage and allow inflammation to settle before definitive repair.
In complex disease, staged treatment is often safer than an aggressive single operation. The plan depends on tract height, branches, previous surgery, existing continence and childbirth-related sphincter injury.
Surgery and Important Risks
Fistulotomy opens a simple low tract and provides high healing rates when only a safe amount of sphincter is involved. Higher tracts need a sphincter-preserving option such as LIFT, which closes the tract between the muscles, or an advancement flap that covers the internal opening.
Endoscopic or laser closure may suit selected patients, but long-term healing is less certain. Plugs and fibrin glue have lower success rates. Risks include bleeding, infection, delayed healing, recurrence, further procedures and impaired control of gas or stool.
Recovery and Follow-up
Open wounds need regular washing or dressings and soft, formed stools. Pain relief and a clear seton-care plan are important. Some drainage is expected while a loose seton remains in place.
Contact the team for fever, increasing swelling, urinary difficulty, uncontrolled pain or suddenly reduced drainage with worsening pressure. Complex repairs need longer follow-up because recurrence may appear later.