Gastro - Crohn's disease

Question 1

describe the common signs and symptoms of CD

Answer 1

Symptoms (chronic relapsing course):

• severe abdo. pain (dominant feature)
• non-bloody diarrhoea
• malaise and fever

Signs:

• weight loss
• mouth ulcers
• anal and peri-anal lesions
• abdo. mass (formed by loops of inflamed small bowel adhering together)

Question 2

suggest possible extra-abdominal features of CD

Answer 2

1. Skin: erythema nodosum or pyoderma gangrenosum
2. Liver: primary sclerosing cholangitis or hepatitis
3. Eyes: iritis, uveitis or episcleritis
4. Joints: inflammatory arthritis or ankylosing spondylitis

Question 3

which Ix would you perform on someone with suspected CD?

Answer 3

1. Bloods
   - FBC: may show anaemia
   - CRP/ESR: indicates active disease and severity
   - UandEs
   - LFTs
   - iron studies, vitamin B12 and folate: assess anaemia
   - coeliac screen (total IgA and tTG): rule out coeliac disease
   - serological markers: ASCA in CD (vs pANCA in UC)
2. Bedside tests
   - faecal calprotectin: rule out IBS (detects colonic inflammation)
   - stool testing and culture, inc. ova, cysts and parasites
   - sigmoidoscopy +/- rectal biopsy: consider in all pts with diarrhoea
3. Imaging
   - ileocolonoscopy + biopsies: 1st line for Dx, with biopsies of terminal ileum and each affected colonic segment
   - CT/MRI: may show bowel wall thickening, obstruction/narrowing, etc.

Question 4

which Ix would you perform to investigate perianal disease?

Answer 4

1. pelvic MRI: accurate and non-invasive

2. examination under anaesthetic: gold-standard if experienced surgeon, may permit concomitant surgery

Question 5

which features seen on colonoscopy support Dx of CD?

Answer 5

Pattern of inflammation forms skip lesions. Can affect any part of GI tract except rectum.

1. hyperaemia
2. cobblestone appearance (superficial and deep ulcers)
3. thickening and fibrosis of bowel wall with lumen narrowing (due to transmural inflammation)

Question 6

Which feature on microscopy investigation of biopsies is pathognomonic for CD?

Answer 6

granulomas

Question 7

how would you induce remission in a pt with first presentation or exacerbation of CD?

Answer 7

1. glucocorticosteroid, e.g. prednisolone, methylprednisolone or IV hydrocortisone
2. consider adding azathioprine or mercaptopurine if 2+ exacerbations in 1 yr
3. infliximab or adalimumab (TNFa blockers): if severe active CD or fistulating CD not responding to conventional Tx

Question 8

how would you maintain remission in a CD pt?

Answer 8

1. conservative: no Tx (smoking cessation is important)
   2, 1st line: AZATHIOPRINE or MERCAPTOPURINE
2. 2nd line: consider METHOTREXATE only in pts who needed this to induce remission, or MESALAZINE (5-ASA) to maintain remission after surgery

Question 9

when would you consider surgery in the Tx of CD?

Answer 9

1. CD limited to distal ileum

2. managing strictures: consider balloon dilatation but if has complications or failure of dilation, consider surgery

Question 10

suggest possible complications of CD

Answer 10

1. strictures - may cause obstruction
2. fistulae - between bowel loops and other bowel, bladder (pneumouria), vagina or skin
3. perforation, acute dilatation and massive haemorrhage can also occur