GI Flashcards
What is Crohn’s disease?
Site
Type
Clinical features (8)
Risk factors (6)
Site:
- whole GI tract, mainly at terminal ileum and caecum
Type: fibrostenotic, inflammatory, fistulizing
Clinical features:
- Constitutional: fever, weight loss
- RLQ abdominal pain
- RLQ palpable mass
- Bowel obstruction
- Watery diarrhoea ± steastorrhea
- Oral ulcers
- stomatitis
- anal fissure/skin tag
Risk factors
- smoking
- prior appendicectomy
- FHx
- Diet - refined sugar, low-fibre diet spicy food
- Hx of infectious GE in past year
- Drugs - NSAIDS, OCP, antibiotics
What is Crohn’s disease?
Pathology
Imaging
Endoscopy
Lab
Pathology:
Transmural inflammation with fistula
Lymphocytic infiltration
Globet cells
Non-caseating granuloma
—> DDx: TB colitis, with case acting granuloma, AFB stain & C/ST if suspected
Endoscopy:
- ileo-colonoscopy with biopsy
- patchy inflammation with skip lesion
- Deep linear ulcer (cobblestone appearance)
- Stricture, abscess, fistula
-spared rectum
Imaging:
- AXR —> dilated bowel, thumbprinting sign, mass in RIF, calcified calculi, sacroiliitis
- CT/MR enteroclysis —> inflammatory vs fibrotic stricture, extraluminal complication, fistula, perianal disease
- Capsule endoscopy (after r/o SB strictures - capsule retention)
- Anorectal USG —> fistulising perinatal CD
- CT colonography
- Interstitial USG
Lab:
- CBC, LRFT, ESR, CRP
- Ca, B12/folate, G6PD, Fe profile
- Antibodies: ASCA
- Stool: culture, microscopy, C.diff toxin PCR
- Faecal calprotectin
What is Ulcerative colitis?
Site
Clinical features (3)
Risk factors (3)
Protective factors (2)
Site:
Rectum +/- colon
Clinical features:
- Constitutional: fever, weight loss
- Diarrhoea (mucus/pus, bloody)
- Urgency/tenemus
Risk factors:
- FHx
- Diet: refined sugar, spicy food, low-fibre diet
- Drug: NSAIDS
Protective factors:
- smoking
- prior appendicectomy
What is Ulcerative colitis?
Pathology
Imaging (3)
Endoscopy
Lab
Pathology:
Mucosal inflammation, without fistula
Neutrophilic infiltration
No Globet cells
No granuloma
Endoscopy:
Colonscopy with biopsy
- Continuous lesion
- Superficial broad-based ulcer
- Rectal involvement
- Caecal patch (in E2)
- Clear demarcation between inflamed
and normal mucosa
- Touch friability, petechiae, bleeding
Imaging:
- AXR —> dilated LB, thumbprinting sign
- CT/MR enteroclysis
- Interstitial USG
Lab:
- CBC, LRFT, ESR, CRP
- Ca, Fe profile, B12/folate
- Antibodies: p-ANCA
- Stool: culture, microscopy, C. Diff toxin PCR
- Faecal calprotectin
Extra-intestinal manifestation of IBD
• Skin: clubbing, oral aphthous ulcer, stomatitis, perianal skin tag, erythema nodosum, pyoderma gangrenosum (a/w sterile abscess), psoriasis, Sweet syndrome (acute febrile neutrophilic dermatosis),
hidradenitis suppurativa
• MSK: peripheral arthropathy (Types 1* & 2^), axial SpA, osteoporosis (fat malabsorption à ↓fat-soluble Ca)
• Blood: anemia (active IBD, Fe / B12 malabsorption, sepsis, azathioprine-induced myelosuppression)
• Ocular: uveitis, episcleritis* (painless), scleritis (painful & vision-threatening)
• Hepatobiliary: fatty liver, liver abscess, gallstone (↓reabsorption of bile salt), PSC (a/w UC)
• Urologic: kidney stone (oxalate stone)
Classification and Disease activity of Crohn’s disease
Montreal phenotypic classification:
Age of onset
Location
Behaviour
Disease activity:
Harvey-Bradshaw Index
Crohn’s disease activity index
CRP level
Classification and disease activity of ulcerative colitis
Montreal phenotypic classification:
Extent
Modified Truelove and Witt’s criteria:
Severe disease if (STEPH) : ≥6 bloody stools/ day, T > 37.8, ESR/CRP > 30, P > 90, Hb < 10.5
—> require urgent admission
Complication of IBD
• Malnutrition: poor oral intake, protein-losing enteropathy, etc.
• Toxic megacolon
• Malignancy (CRC, SB cancer, cholangiocarcinoma): higher risk in UC; surveillance colonoscopy Q3y
• Stricture ( IO), fistula, abscess, perianal diseases (CD)
Toxic mega colon
Definition
Pathogenesis
Clinical features
Ix
Mx
Definition:
total or segmental non-obstructive colonic dilatation associated with systemic toxicity
Pathogenesis:
severe inflammation that paralyses colonic smooth muscle, causing colonic dilation
Clinical features:
- Severe bloody diarrhoea >10x/day
(Reduced stool frequency not necessarily sign of improvement: ¯stool frequency + abdominal distension +
abdominal pain strongly suggestive of impending perforation)
- Systemic toxicity: Fever, hypotension, tachycardia, dehydration, confusion
Ix:
- AXR (transverse colon > 6cm / caecum > 9cm), inflammatory pseudopolyps (mucosal islands)
- Avoid colonoscopy: risk of perforation
Mx
- Resuscitation and close observation of vitals, stool chart, weight
- Complete bowel rest: NPO ± TPN
- NG tube decompression
- IV Broad-spectrum antibiotics
- IV methylprednisolone (after antibiotics initiated)
- Subtotal colectomy + ileostomy if failed medical treatment (50%)
Medical treatment of IBD
Lifestyle:
- smoking cessation
- Avoid NSAIDS
- Exclusive Enteral Nutrition / PEN with exclusion CD diet
- Dairy free diet for acute colitis
Antibiotics:
For perianal disease in Crohn’s disease
Aminosalicylates (e.g. mesalazine, sulphasalazine; monitor CBC, RFT):
- For ulcerative colitis
- For induction + maintaining remission
mesalazine / 5-ASA,
• E1: suppository (distal 10cm of rectum)
• E2: enema (up to splenic flexure)
• E3: PO + enema
Cancer protection effect: lower risk of CRC
Corticosteroid (Budesonide):
- For induction of mild-to-moderate CD
- Route: PO, IV (severe UC), PR enema (topical Tx for UC: Budenofalk)
- Prefer: budesonide CIR* 9mg/day x 4-8 weeks (high first-pass effect to limit systemic S/E)
- If long-term use: Ca + vit D supplement
Immunosupression (azathioprine) (monitor CBC & LFT):
For maintenance of remission
Require > 3mo to have benefits
Examples:
• Azathioprine (S/E: macrocytosis) 1.5-2.5mg/kg/d: check TPMT^ and NUDT15 activity (risk: leucopenia)
• 6-mercaptopurine
• Methotrexate IM/SC weekly (if refractory): PO folic acid 5mg 3 days after each dose
Others: IV cyclosporin / PO tacrolimus used for rescue therapy in severe UC
Biologics:
Synergistic
- Anti-TNF: (S/E: paradoxical psoriasis, reactivate TB, optic neuritis, risk of
lymphoma esp. NHL, C/I: Hx of these)
o IV Infliximab (chimeric): 0, 2, 6 weeks —> Q8week, risk of ATI@
o SC Adalimumab (humanized): Q2 weeks
- Anti-α4β7 integrin: gut-selective, lower risk of serious infection, slower onset
o IV Vedolizumab: 0, 2, 6 week —> Q8week
- Anti-IL12/23
o Ustekinumab (Stelara): IV BW-based loading —> SC at 8 week —> SC Q12week
- JAK inhibitors: PO tofacitinib (S/E: herpes zoster infection)
Surgical treatment of IBD
Last resort:
aim at bowel conservation
Indications:
- Stricture / obstruction / fistula refractory to medical treatment
- Severe perianal disease
- Malignancy / high-grade dysplasia (prophylactic colectomy)
Post surgery: 6-9 months colonoscopy
Management of acute flare-up in IBD
Causes
o Triggers (e.g. NSAID use, smoking)
o Drug non-compliance
o GI infection
Investigations:
first rule out infection (esp. TB, CMV)
o Bloods: CBC (anemia), CRP/ ESR
o AXR daily (toxic megacolon)
o Stool: faecal calprotectin, virus (norovirus, CMV), bacteria (C/ST, GDH antigen, C. diff toxin), parasite
Management of severe flare-up
o Hydration & nutrition
o IV methylprednisolone
o Rescue therapy after 3-5d (infliximab / cyclosporine)
o Surgery if no improvement for 4-7d
Monitoring of IBD
- Clinical: BO frequency, PR bleeding, change in body weight, S/E of medications (e.g. hepatotoxicity, alopecia,
leucopenia, opportunistic infection, Cushingoid features) - Biochemical: ESR, CRP & faecal calprotectin
- Endoscopic:
o CD: disease extent, UGI involvement
o UC: mucosal healing
For UC - CRC screening
- chromo-endoscopy
- repeat colonoscopy every 1-2y
