Diagnosis of Anal Fistula
Diagnosis of anal fistula typically involves a physical examination, medical history, and — in some cases — imaging tests to assess the extent of the fistula. Early and accurate diagnosis is essential to plan effective treatment.
Step 1: Medical History
Your doctor may ask:
- Have you had a recent anal abscess or drainage?
- Do you experience recurring pain or pus discharge near the anus?
- Any history of Crohn’s disease, tuberculosis, or rectal surgery?
- Is there bleeding or a visible lump?
Step 2: Physical Examination
A visual inspection of the anal area is often enough to spot:
- An external opening
- Ongoing discharge
- Skin irritation or inflammation
During the exam, the doctor may gently press the area to check if pus or fluid comes out.
Step 3: Digital Rectal Exam
The doctor inserts a gloved, lubricated finger into the rectum to feel for abnormalities:
- Internal openings
- Indurations (firm tracts)
- Tenderness or swelling
This helps assess the depth and direction of the fistula.
Step 4: Imaging (for complex or deep fistulas)
In certain cases, doctors need further imaging to map the full extent of the fistula:
- MRI (Magnetic Resonance Imaging) – The most accurate tool for complex or multiple tracts
- Specialised centres may use endoanal ultrasound for diagnosis and assessment
- Fistulography – X-ray using contrast dye (less commonly used today)
In South Africa, both public and private healthcare providers offer diagnostic imaging, but access to MRI scans can be limited outside major centres.
Next, let’s look at the treatment options for anal fistulas.
