Anal Fissure And Fistula-in-ano Flashcards
What is an anal fissure?
Tear in the mucosal lining of the anal canal. Most commonly due to trauma from defecation of hard stool.
How can anal fissures be classified?
Acute <6weeks
Chronic >6weeks
Primary
Secondary - IBD
What are the risk factors for anal fissures?
Constipation
Dehydration
IBD
Chronic diarrhoea
What presenting features of anal fissure?
Intense pain post-defecation
May be bright red bleeding or itching post defecation
What may be seen on examintion of anal fissures?
DRE very painful - can be visible and/or palpable
Most in posterior midline
May need examination under anaesthesia (EUA) or proctoscopy
What are the diffrential diagnosis for anal fissures?
Haemorrhoids
Crohns disease
UC
Anal cancer
What is the medical management for anal fissures?
Reduce risk factors
Adequate analgesia
Increase fibre and fluid intake
Stool softening laxatives
Topical anaestheics - lidocaine
GTN cream or diltiazem cream - increase blood supply and relaxes internal anal canal spinchter.
When is surgical managment used for anal fissures and what is it?
Chronic fissure when medical management failed for 8 weeks
Botox injections - into the internal anal sphincter
Lateral sphincterotomy
Reccurance is about 1-5%
What is an perianal fistula?
Abnormal connection between anal canal and perianal skin
Majority associated wth anorectal abscess
What is the parks classification of anal fistulas?
Inter-sphincteric - most common
Trans-sphincteric
Supra-sphincteric
Extra-sphincteric
What are the risk factors for anal fistulas?
Typically occur as a result of anorectal abscess
IBD - mainly crohns
Systemic disease - DM
History of trauma
Previous radiation therapy to anal region
What are the clinical features of anal fistulas?
Reccurent perianal abscesses
Intemintant or continous discharge onto the perineum - including mucus, blood, pus or faeces
On examintion an external opening on the perineum may be seen, fibrous tract may be felt underneath the skin on DRE.
What is the goodsall rule in anal fistulas?
Predcit trajectory of fistula tract depending on loctaion of external opening:
External opening posterior to the transverse anal line – fistula tract will follow a curved course to the posterior midline
External opening anterior to the transverse anal line – fistula tract will follow a straight radial course to the dentate line
What is the investigation of chocie for perianal fistula outside an emergency setting (i.e.anorectal abscess)?
MRI imaging - visulaise anatomy of tract
What are the surgical options for perianal fistulas?
Depends on cause and size:
Fistulotomy - surperfical disease
Placement of a seton - high tract disease
May require repeat procedures
