Anal Fissure

Question 1

What is an anal fissure?

Answer 1

An anal fissure is a tear in the squamous lining of the lower anal canal, commonly caused by passing of hard faeces. Pain when defecating causes spams, these cause reduced blood flow (by constriction of the inferior rectal artery), it also causes hesitation in defecating, causing more constipation and more hard stools.
Anal fissures are classed as acute (<6 weeks) or chronic (>6 weeks)

Question 2

What are the causes of an anal fissure?

Answer 2

Causes:
Commonly – Primary Idiopathic, Hard Faeces
Others – Rectal Cancer, Crohns Disease, STD (HIV, Syphilis, Herpes)

Question 3

What will you find on a history taking of an anal fissure?

Answer 3

Symptoms:
Previous hard stools/straining 
Pain on defecation – Like passing “Shards of glass” and may persist for a few hours after passing stool 
Tearing sensation on passing stool
Fresh blood on toilet paper
Anal Spasm

Risk Factors:
Recent Constipation
Opioid Use

Specific Questions to ask:
Recent bowel habit – Specifically any constipation
Red Flag Symptoms – Weight Loss, Rectal Discharge, Abdominal Pain, Family history of any colorectal cancer or inflammatory bowel disease, recent change in bowel habit

Differentials:
Haemorrhoids – Itching and not painful on defecation, may see a haemorrhoid on examination

Question 4

What will you find on examination of a patient with an anal fissure?

Answer 4

Abdomen:
Feel for any masses

Anus
Small fissure on the anus– normally posterior/anterior and in the midline
Chronic Fissures – May have skin tags attached to them
Indications that cause may not be hard stools – Multiple fissure or fissures on the lateral aspects of the anus

Question 5

What is the treatment of an anal fissure?

Answer 5

What is the treatment: Refer any anal fissures that were not caused by hard faeces to the appropriate specialist
Lifestyle:
Fibre
Fluids
Stool Softeners
Hygiene advice - encourages healing and stops infection
Educate on straining

Medical:
Paracetamol/ibuprofen – For Mild Pain
Topical 5% Lidocaine (Anaesthetic) – If Severe pain
GTN ointment – If prolonging more than 1 week
Topical Diltiazem – Can be used if fissure not healing (after 6-8 weeks)

Surgical:
Lateral Partial Internal Sphincterotomy – Last line