GI - IBD Pathology and Presentation

Question 1

Outline the pathological (macroscopic) differences between UC and Crohn’s

Answer 1

-Location: (UC) Rectum + colon +- backwash ileitis vs (Crohns) Mouth to anus, espcially terminal ileum
-Distribution: contiguous vs skip lesions
Strictures: no vs yes

Question 2

Outline the pathological (microscopic) differences between UC and Crohn’s

Answer 2

• Inflammation: muscosal vs transmural
• Ulceration: shallow and broad vs deep cobblestone mucosa
• Fibrosis: none vs marked
• Granulomas: none vs present
• Pseudopolyps: marked vs minimal
• Fistulae: none vs present

Question 3

Describe a UC presentation

Answer 3

• Systemic: fever, malaise, anorexia, wt loss (in active disease)
• Abdominal: diarrhoea. blood and mucus (PR), abdo discomfort, tenesmus and faecal urgency
• Signs Abdominal: fever, tender and distended abdo
• Signs extra abdominal: Skin (clubbing, erythema nodosum, pyoedema), Eyes (iritis, conjunctivitis, episcleritis, scleritis)

Question 4

Describe UC complications

Answer 4

• Toxic megacolon (diameter of >6cm, risk of perforation)
• Bleeding
• Malignancy (10% for evert 10 years)
• Cholangiocarcinoma
• Strictures leading to obstruction
• Venous thrombosis

Question 5

Describe a Crohn’s presentation

Answer 5

• Systemic: fever, malaise, anoresia, wt loss (in active disease)
• Abdominal: diarrhoea (usually not bloody), abdo pain
• Abdominal signs: abdo tendernes, RIF mass, perianal abscesses, fistulae, tags, anal and rectal strictures
• Extra abdo signs: arthritis (non deforming and asymmetrical), sacro-iliitis, gallstones/fatty liver, amyloidosis and oxalate renal stones

Question 6

Complications in Crohn’s

Answer 6

• Fistulae: Entero-colonic (diarrhea), entero-vesical (freqeuncy/UTI), entero-vaginal, perianal
• Strictures: obstruction
• Abscesses (abdominal or anorectal)
• Malabsorption: fat (steatorrhea/gallstones), B12 (megalobastic anaemia), Vit D (osteomalacia), protein (oedema)
• Toxic megacolon and Ca can occur but < than UC

Question 7

UC: prevalence:

Answer 7

• Most common form of IBD

- Most prev among Caucasian pop, 15-25ya and 55-65ya

Question 8

UC: differentials

Answer 8

• Crohn’s (primary Dx)
• Chronic infections (schisto, giardia, TB)
• mesenteric ischaemia
• radiation colitis
• Malignancy
• IBS
• Coeliac disease

Question 9

UC: investigations - bloods and samples

Answer 9

• Bloods: FBC, U&Es, CRP, LFT and clotting - examine for anaemia, low albumin, raised CRP and WCC
• Faecal calprotectin test: in patients with recent onset lower GI problems
• Stool sample: exclude campy, shigella, salmonella, c diff

Question 10

UC: investigations - imaging and others

Answer 10

• Colonoscopy with biopsy: provides definitive Dx - characteristic findings are continuous inflammation with ulcers, visible pseudopolyps
• Can do flexi-sig
• Acute exacerbations: AXR helps determine whether there is toxic megacolon/bowel performation
• Chronic UC cases may show lead-pipe colon,
• Ba/gastrograffin enema

Question 11

UC: Mx- acute severe UC

Answer 11

• Resus: Admin, IV, NBM
• Hydrocortisone: IV 100mg QDS + PR
• Transfuse if required
• Thromboprophylaxis: LMWH
• Monitoring: bloods (FBC, ESR, CRP, U&E), vitals + stool chart, AXR
• avoid anti-motility drugs (loperamide) in acute attacks - can precipitate toxic megacolon
• ABX do not seem to benefit - not routinely recommended, may be used if megacolon, perforation or undertain Dx

Question 12

UC: Acute complications

Answer 12

• Performation
• Bleeding
• Toxic MC
• VTE

Question 13

UC: stepwise treatment approach

Answer 13

• Mild-mod (proctitis): Step 1 (topical mesalazine or sulfazalaxine), step 2 (add oral pred + oral tacrolimus)
• Mild to mod (extensive inflammation): Step 1 (high oral dose mesalazine or sulfazalazine) + step 2 as above
• Severe: Step 1 (IV corticosteroids and assess the need for surgery) + Step 2 (add infliximab if no short term response)

Question 14

UC: maintaining remission

Answer 14

• Can be maintained with immunomodulators (mesalazine/sulfasalazine)
• Pts at increased risk of colorectal malignancy t/f: colonoscopuc surveillance offered for pts with 10+ ya Hx of UC

Question 15

UC: further Mx

Answer 15

• IBD nurse specialists/pt support groups
• Enteral nutritional support: considered in young pts with growth concerns
• ABX: only offered with obvious concurrent disease (ciprofloxacin/metronidazole)

Question 16

UC: surgical Mx

Answer 16

• 30% UC pts will need surgery
• Indication for acute surgical TRX: toxic MC, perforation, massive haemorrhage, failure to respond to medical Rx
• Indications for elective surgery: chronic symptoms, carcinoma/high grade dysplasia
• Proceduces: sub-total colectomy (preservation of rectum) OR total proctocolectomy (curative - pt needs ileostomy)

Question 17

Crohn’s: prevalence and risk factors

Answer 17

• 150/100 000 in uk
• peak age between 15-30
• remitting/relapsing course
• Risk factors (same as UC): family Hx, smoking, white european descent (esp Ashkenzi Jews). appendicectomy (increases risk of developing CD after surgery

Question 18

Crohn’s: Ix - bloods and stool

Answer 18

• FBC, LFT, CRP/ESR, haematinics (Fe, B12, folate), blood cultures
• Stool: exclude campy, shigella, salmonella and c diff

Question 19

Crohn’s: Ix - imaging and others

Answer 19

• A/CXR: obstriction/performation
• Faecal caprotectin: raised in IBD but normal in IBS
• Colonoscopy with biopsy: gold standard (avoid during active flare) - can do flexi sig
• Barium swallow: less common - can show strictures
• CT: done in severe flare - shows obstruction, perf, collection, distuale
• pelvic MRI: shows perianal disease

Question 20

Crohn’s: Mx - severe attack

Answer 20

• Resus: admit, NBM, IV hydration
• hydrocostisone: IV/PR
• thrombopro: LMWH
• Dietician review: elemental diet or parenteral nutrition
• Monitoring: I/O chart
• Pt improves: switch to oral TRX (oral pred 40mg/d)
• No improvement: methotrexate +/- infliximab and surgical talk

Question 21

Crohn’s: Mx - inducing remission

Answer 21

• Resus as above
• High fibre diet/vitamine supplements
• corticosteroid therapy in ascending order (pred, methotrexate, infliximab)

Question 22

Crohn’s: Mx - maintaining remission

Answer 22

• Azathroprine/ mercaptopurine: monotherapy to maintain remission
• Increased risk of colorectal malignancy t/c olonoscopic surveillance offered

Question 23

Crohn’s: Mx - surgery

Answer 23

• Never curative in Crohn’s- should be conservative
• Emergency: failure to respond to medical Rx, intestinal obstruction/perf/massive haemorrhage
• Elective: abscess/fistula, perianal disease, chronic ill health, carcinoma
• Most common is ileocaecal resection with primary anastomosis btw ileum and ascending colon

Question 24

Crohn’s: Mx - further Mx

Answer 24

• IBD nurse specialist/support groups
• Enteral nutrition in young pts (growth concerns)
• ABX only offered in cases of concurrent infection (ciprofloxacin/metronidasole)