Lower GI Flashcards
Types of anal fissures
Tear in squamous epithelium of anal canal
- Primary => usually posterior line
- Secondary => varying locations (constipation, Crohn’s disease, pregnancy)
AND
- squamous epithelium => lower 1/3 anal canal => somatic innervation => usually visible on inspection
- columnar epithelium => upper 2/3 anal canal => visceral innervation => not visible on inspection
Ix for anal fissure
NO DRE
- that would be v painful, don’t do that
- clinical diagnosis instead
Presentation of an anal fissure
Young
Painful rectal bleeding on defecation
Blood on tissue
Chronic ulcer => sentinel pile/skin tag
Mx for anal fissures
Pain
- paracetamol/ibuprofen
- topical lidocaine
- topical GTN/diltiazem if > 1 week
Constipation
- increase fibre/fluid intake
- laxative; bulk forming => osmotic => stimulant
Types of haemorrhoids
External
- below dentate line, painful
Internal
I - project into lumen, not palpable
II - prolapse w/ straining, spontaneously reduce; above dentate line, not painful
III - prolapse w/ straining, manually reducible
IV - irreducible
Presentation of haemorrhoids
Usually painless rectal bleeding
Large haemorrhoids cause rectal fullness/tenasmus/soiling
Ix and mx for haemorrhoids
Ix: anaemia, protoscopy
Mx:
I - stool softening (fibre/fluid/laxative)
II - rubber band ligation/injection sclerotherapy
III - large grade 3/4; haemorrhoidectomy
Complications of haemorrhoids
Thrombosis of external haemorrhoids
- severe pain and purplish oedematous perianal mass, <72 hrs need to surgically incise
Strangulation of internal haemorrhoids
- severe pain, urgent haemorrhoidectomy
Causes of colorectal cancer
*usually adenocarcinoma
Genetic
- FHx, FAP (APC gene), HNPCC [AD]
Male
Environment
- alcohol, smoking, diet, obesity
Other
- IBC (UC>Crohn’s), adenomatous/neoplastic polyps
Sx for colorectal cancer
Abdo pain, fatigue, wt loss:
Right-sided => anaemia (less common, present later)
Left-sided => PR bleeding, change in bowel habit, tenasmus, mass on DRE, can present w/ obstruction (more common, present earlier)
Ix for colorectal cancer
I - bloods: FBC (anaemia), LFTs (mets), CEA (tumour marker)
II - colonoscopy (GOLD STANDARD); Duke’s staging
III - barium enema; apple core stricture
Mx for colorectal cancer
I - surgery => resection, hemicolectomy, colectomy
II - radiotherapy, chemotherapy
What screening is done for colorectal cancer?
FIT = 60-74yo every 2 years
FlexiSig at 56 yo
Extra manifestations specific to the two IBDs
UC: uveitis, PSC/cholangicarcinoma
Crohn’s; episcleritis, gallstones + kidney stones
Compare UC and Crohn’s
a) RFs
b) Pathology
a) RFs:
Crohn’s = smoking, UC = HLA-B27
b) Pathology:
Crohn’s = anus -> mouth, discontinuous inflammation, transmural
UC = rectum -> ileco-caecal valve, continuous inflammation, mucosa only
Compare UC and Crohn’s
a) Presentation
b) Complications
a) Presentation:
Crohn’s = right-sided abdo pain, diarrhoea, B sx, perianal lesions and mouth ulcers, malabsorption
UC = left-sided abdo pain, bloody diarrhoes, B sx
b) Complications:
Crohn’s = fistulae, abcess
UC = toxic megacolon, colorectal cancer