Anal Fissure Flashcards
What is an anal fissure?
longitudinal or elliptical tears of the squamous lining of the anal canal (distal to dentate line)
How are anal fissures classified?
Acute: <6w OR Chronic: >6w
Primary (due to local trauma) OR Secondary (due to underlying disease)
Give 3 risk factors for anal fissures
Constipation
IBD
STIs e.g. HIV, syphilis, herpes
Describe the distribution of primary anal fissures
90% of all anal fissures located at posterior commissure (6 o’clock in lithotomy position)
List 4 potential causes of trauma leading to primary anal fissures
Chronic constipation/ diarrhoea
Low fibre diet
Anal sex
Vaginal delivery
Describe distribution of secondary anal fissures
May occur lateral or anterior to posterior commissure
List 5 underlying conditions that may cause anal fissures
Previous anal surgery
IBD
Granulomatous disease e.g. TB
Infections e.g. chlamydia, HIV
Malignancy e.g. Leukaemia
List 4 symptoms of anal fissures
Sharp, severe pain during defecation
Rectal bleeding (bright red + minimal)
Perianal pruritus
Chronic constipation
Describe appearance of anal fissure on examination
Superficial/ deep laceration in anal canal
Give 3 signs of fibrotic and infective changes in chronic anal fissures
Wide, raised edges
Skin tags (sentinel pile) at fissures distal end
Hypertrophied anal papillae at fissures proximal end
Describe management of acute anal fissures
Soften stool (High fibre diet, high fluid intake, bulk forming laxatives)
Lubricants e.g. petroleum jelly before defecation
Topical anaesthetics
Analgesia
Name 2 bulk forming laxatives
Fybogel
Docusate
Describe the management for chronic anal fissure
Continue initial Mx
1. Topical GTN
2. If ineffective after 8w, refer to secondary care
What can be performed in chronic anal fissure refractory to medical management?
Sphincterotomy
OR
Botulinum toxin injection
Give 2 complications of anal fissures
Chronic anal fissure (if left untreated)
Incontinence (post-sphincterectomy)
What is the prognosis of anal fissures?
In most: fissure will heal within ~ 1w
Tx aims to ease pain by keeping the stools soft + relaxing the anal sphincter to promote healing
Describe the diagnosis and investigation of anal fissures
Clinical dx
If anal sphincter deficits suspected; may do anal US to examine the internal + external sphincter
DRE NOT conducted in suspected anal fissures due to immense pain
What is the pain caused by anal fissures compared to?
“passing broken glass”
