Anus Flashcards
What do haemorrhoids consist of?
Cluster of vascular tissue, smooth muscle and connective tissue lined by normal epithelium of the anal canal
Risk factors for haemorrhoids
1) Decreased venous return (increased intra-abdominal pressure) - pregnancy, constipation + straining
2) Increased rectal vein pressure - obesity, prolonged sitting
3) Age - degeneration of collagen in connective tissue that fixes haemorrhoids to anorectal wall
Two types of haemorrhoids
Internal & external haemorrhoids
Internal haemorrhoids clinical presentation
Rectal bleeding, pain, mucus discharge, pruritus, prolapse
Painless, fresh bright red PR bleed after defecation - comes and goes (not like CRC which persists and progresses)
Usually painless, unless thrombosed, prolapsed w edema, strangulated
External haemorrhoids clinical presentation
Usually asymptomatic
Acute local thrombosis can cause extreme pain
- rupture of vein causing tense
hematoma formation
- pt present w painful perianal
subcutaneous nodule
- pain for 2-3 days, resolves spontaneously
Internal haemorrhoids classically present __ the pectinate line, at ___ o’clock in ___ position
above
3, 7, 11 o’clock in lithotomy position
Grading for internal haemorrhoids
Banoy grading
Grade I: Non-prolapsing
Grade II: Prolapse on straining, spontaneous reduction
Grade III: Prolapse spontaneously/on straining, requires manual reduction
Grade IV: Chronically prolapsed, irreducible
Grade ___ internal haemorrhoids can use non-operative ___ technique
II
rubber band ligation
Where do anal fissures occur
Split in the anoderm (distal to the pectinate line)
90% of anal fissures occur ____, 10% occur ___
posterior to anal midline
anterior
But 25% anterior in females
Clinical presentation of anal fissure
Tearing pain w defecation
Anal spasm lasting for hours post defecation
Haematochezia
Pruritus/skin irritation
Pts with acute anal fissure often unable to tolerate ___
DRE
Chronic anal fissures present with
Hypertrophic anal papilla
Boat shaped, heaped up edges
Exposing muscle internal sphincter
Sentinal skin tag @ distal end
What are anal fistulas?
Abnormal communications - hollow tracts lined w granulation tissue connecting primary opening inside anal canal to secondary opening in perineal skin.
Usually associated w anorectal abscess
Goodsall’s rule
Rule for anal fistulas
Fistula opening posterior to transverse anal line: curved tract that opens into anal canal midline
Fistula opening anterior to transverse anal line: straight tract into anal canal
Types of fistulas
1) Intersphincteric: internal sphincter -> intersphincteric space -> perineum
2) Trans-sphincteric: internal & external sphincters -> ischiorectal fossa -> perineum
3) Supra-sphincteric: intersphincteric space -> above puborectalis muscle -> ischiorectal fossa -> perineum
4) Extrasphincteric: perianal skin -> levator ani -> rectal wall
Imaging for anal fistulas
MRI (gold standad)
Endoanal ultrasound
What causes anorectal abscess?
Infection of anal glands in the anal crypts at pectinate line
Initial abscess in intersphincteric space (5%), spreads to
a) superficial to external sphincter - perianal (60%)
b) through external sphincter -> ischiorectal fossa (20%)
c) deep to external sphincter -> supra-levator space
Clinical presentation of anorectal abscess
Pain (dull, throbbing) and swelling, worse on sitting & bowel movement
Fever
Erythematous, palpable swelling, fluctuant mass
What causes anal intraepithelial neoplasia? (AIN)
HPV 6, 11, 16*, 18
HIV
Spread via anal intercourse
What grade of AIN is most dangerous?
AIN III / high grade squamous intraepithelial lesion - 10% progresses to anal carcinoma
Presentation of AIN
Pruritus, bleeding, pain, discharge
Most anal cancers are ___ (histo)
squamous cell carcinomas
10% adenocarcinoma
Risk factors for anal cancer
HPV 16, 18
HIV
Anal intercourse
History of genital warts
