- Indication
- Used primarily for chronic radiation proctitis with bleeding due to friable telangiectatic mucosa
- Considered after failure of conservative treatments (e.g. Sucralfate enemas, steroids, argon plasma coagulation)
- Prepare the solution
- 4% to 10% formalin solution is used (most commonly 4%)
- Must be handled with care — it’s a potent irritant and fixative
- Use appropriate PPE (gloves, mask, gown), and perform in a well-ventilated area or under suction
- Explain the procedure and obtain consent
- Inform the patient it may cause burning, discomfort, or urgency during and after
- Warn about transient worsening of symptoms and rarely, ulceration or stricture
- Position the patient
- Left lateral (Sims) position is commonly used
- Ensure easy access to the anus and rectum
- Insert anoscope or rigid sigmoidoscope
- Clean the rectal vault with gentle suction or irrigation if soiled
- Visualise the area of bleeding/telangiectasia
- Apply formalin-soaked pledgets
- Soak gauze pledgets or cotton balls in formalin (e.g. 4%)
- Use forceps to apply them directly to the bleeding mucosa
- Hold in place for 2–3 minutes (some protocols allow up to 5 minutes, depending on tolerance)
- Avoid contact with healthy mucosa or anoderm to reduce pain and chemical injury
- Alternatively: instillation method
- Slowly instill 20–40 mL of 4% formalin into the rectum via a catheter tip syringe
- Ask patient to retain for 2–4 minutes, then drain completely by gravity or suction
- Less controlled but used when bleeding is diffuse and widespread
- Irrigate thoroughly
- After exposure time, flush the rectum copiously with saline to neutralize and dilute residual formalin
- Remove any gauze carefully if used
- Monitor for immediate complications
- Some discomfort or cramping is expected
- Rare complications: ulceration, pain, tenesmus, stricture (especially with repeated or high-concentration use)
- Follow-up
- May need repeat applications at 2–4 week intervals depending on response
- Most patients experience significant reduction in bleeding after 1–3 treatments
- Arrange follow-up endoscopy if bleeding persists or symptoms worsen