Synopsis
Recognise a typical anal fissure, investigate atypical disease, prescribe an eligible topical treatment and choose escalation that respects existing sphincter function and continence.
- A fissure typically causes sharp defaecatory pain followed by pain lasting minutes to hours, with a small amount of fresh blood.
- A posterior or anterior midline tear is typical; lateral or multiple lesions need a broader inflammatory, infective and malignant differential.
- Correct traumatic stool consistency first; chronic symptoms may need topical sphincter relaxation after an eligibility and medication check.
Key red flags
Lateral, multiple or otherwise atypical fissures warrant evaluation for Crohn disease, infection or malignancy.
Severe continuing pain with an unrevealing superficial examination may require examination under anaesthesia to exclude a deep collection.
Baseline leakage, previous obstetric sphincter injury or earlier anal operations materially alters the safety of sphincter division.
Investigation priorities
Identify a typical tear while limiting avoidable pain and further trauma.
Management branches
A 37-year-old woman has ten weeks of painful bowel opening despite correction of hard stools.
- Gentle inspection shows a chronic posterior midline fissure without an atypical ulcer or swelling. She has no baseline leakage, obstetric injury, pregnancy or breastfeeding, nitrate/PDE5 use, recurrent headache, hypotension or listed cardiac, cerebral or ocular contraindication. Renal and hepatic history is unremarkable. Her stool is now soft, but pain persists after defaecation.
- Following the eligibility check she applies a measured 2.5 cm strip of Rectogesic 4 mg/g, approximately 375 mg ointment containing 1.5 mg GTN, circumferentially inside the anal canal using a covered finger every twelve hours. She is shown the carton measure and told to stop and seek review for significant dizziness, troublesome headache or increased bleeding. Treatment stops when pain resolves and must not exceed eight weeks.
Key medicines
Rectogesic glyceryl trinitrate 4 mg/g rectal ointmentFor adults aged eighteen or over with chronic fissure pain after conservative failure, apply a 2.5 cm strip, about 375 mg ointment containing 1.5 mg GTN, intra-anally every twelve hours with a covered finger. Apply circumferentially to the canal to the distal finger joint. Continue until pain abates, at most eight weeks.Contraindications include nitrate/excipient allergy; PDE5 inhibitors such as sildenafil, tadalafil or vardenafil; other organic nitrates/NO donors; hypotension, postural hypotension or uncorrected hypovolaemia; raised intracranial pressure or inadequate cerebral circulation; migraine or recurrent headache; aortic/mitral stenosis, hypertrophic obstructive cardiomyopathy, constrictive pericarditis or tamponade; marked anaemia and closed-angle glaucoma. Do not use during pregnancy; breastfeeding use is not recommended. Severe renal/hepatic disease requires caution, with no defined adjustment and limited elderly data. Review alcohol, antihypertensives, diuretics, other vasodilators, tricyclics, acetylcysteine and dihydroergotamine. Stop and reassess excessive hypotension, troublesome headache or increased haemorrhoidal bleeding; persistent pain needs diagnostic review.
Fybogel Orange 3.5 g ispaghula sachetsAn eligible adult may take one sachet in the morning and one in the evening, stirred into at least 150 mL liquid and consumed promptly after meals. Keep half to one hour clear of other oral medicines and avoid dosing immediately before bedtime. Review after three days if symptoms persist or stool has not passed.Exclude known allergy to ispaghula husk or any Fybogel excipient, unexplained rectal bleeding, a sudden bowel-habit change lasting over two weeks, failure to pass stool after a laxative, faecal impaction, intestinal narrowing or obstruction, reduced gut motility, oesophageal disease and swallowing or throat problems. Never swallow dry granules. Opioid coadministration requires medical supervision; review thyroid replacement, diabetes treatment and delayed absorption of other medicines. Consider potassium restriction in renal disease and aspartame in phenylketonuria. Pregnancy/breastfeeding use can be considered after inadequate dietary change. Stop for new abdominal pain, allergic symptoms or choking.