General - Anorectal Flashcards
(89 cards)
Define an anal fissure
Tear in the mucosal lining of the anal canal
How are anal fissures classified?
Acute: <6wks
Chronic: >6wks
What are the risk factors for anal fissures?
Inflammation or trauma to anal canal:
- Constipation
- Dehydration
- IBD
- Chronic diarrhoea
What are common presenting features of anal fissures?
- Intense pain post defecation (lasting several hours)
- Bleeding (bright red on wiping)
- Itching
Where do anal fissures most commonly occur?
Posterior midline
How is an anal fissure often diagnosed?
DRE conducted anaesthesia
Fissures can be identified upon proctoscopy
How are patients with anal fissures medically managed?
- Increase of dietary fibre and fluids
- Stool softening laxatives (eg. movicol or lactulose)
- GTN or diltiazem cream
Why is GTN or diltiazem cream used?
Increases blood supply to the region and relaxes the internal anal sphincter –> puts less pressure on the fissure and promotes healing and reducing pain
When is surgical therapy used to treat anal fissures?
Chronic fissures where medical treatment has failed
What surgery is indicated for anal fissures?
Lateral sphincterotomy
Define an anal fistula
An abnormal connection between the anal canal and the perianal skin. Associated with anorectal abscess formation
What risk factors are there for anal fistula formation?
- Anal abscess
- IBD
- Systemic disease eg. TB, Diabetes, HIV
- History of trauma
- Previous radiation therapy to anal region
What will an anal fistula commonly present with?
- Intermittent or continuous discharge
- Severe pain
- Swelling
- Change in bowel habit
- Systemic features of infection
What may be found on examination of an anal fissure?
- An external opening on the perineum (fully opened or covered in granulation tissue)
- Fibrous tract may be felt on DRE
What is the Goodsall rule used for?
Used to predict the trajectory of a fistula tract
What does the Goodsall rule predict in a fistula tract with the external opening POSTERIOR to the transverse anal line?
Fistula tract will follow a curved course to the posterior midline
What does the Goodsall rule predict in a fistula with an opening ANTERIOR to the transverse anal line?
Fistula tract will follow a straight radial course to the dentate line
What imaging modality is indicated for an anal fistula?
Rigid sigmoidoscopy - visualised the opening in the tract in the anal canal
Briefly describe Park’s classification system
- Intersphincteric fistula (most common)
- Transphincteric fistula
- Suprasphincteric fistula (least common)
- Extra sphincteric fistula
What surgical treatment is available for anal fistulas?
- Fistulotomy
- Seton placement
- +/- Opening perianal skin adjacent to external opening
When should surgery not be performed for an anal fistula?
- If patient is asymptomatic –> conservative
- Acute anorectal abscess
In which types of anal fistulas are there higher risks of incontinece post operatively?
High tract course fistula (travels through more subcut tissue and muscle)
What is thought to cause anorectal abscesses?
Plugging of the anal canal ducts causing stasis, allowing the normal bacterial flora to overgrow and cause infection
What are the common causative organisms involved in anorectal abscesses?
E coli
Bacteriodes
Enterococcus