Crohn's Disease

Front 1

What is the typical age of presentation for Crohn's disease?
What are the common presenting symptoms?

Back 1

i) 16-30 years
ii) diarrhoea with or without bleeding, fever, abdominal pain, weight loss and fatigue

Diarrhoea - excessive fluid secretion and impaired fluid absorption by inflamed small or large bowel, bile salt malabsorption due to an inflamed or resected terminal ileum, steatorrhea related to loss of bile salts

Front 2

What are the treatment options for Crohn's disease?

Back 2

Medical and surgical (80% of patients with Crohn's have surgery at some stage)

Set-up versus top-down therapy

i) Mesalazine for mild-mod active Crohn's disease is little better than placebo
ii) Corticosteroids effectively induce remission but do not prevent relapse. Corticosteroids with low systemic bio availability, such as budesonide, are preferred for mild or moderately active Crohn's disease.
iii) Antibiotics are appropriate for septic complications and PERIANAL disease
iv) Biological therapy - infliximab, adalimumab
Immunomodulators - azathioprine, 6-mercaptopurine or MTX help to maintain remission and are increasingly considered sooner rather than later

Front 3

What are the major side effects of azathioprine?

Back 3

Myelosuppression, hepatitis and pancreatitis

Front 4

Before starting azathioprine which enzyme should be measured?

Back 4

Thiopurine methyltransferase, the enzyme involed in the conversion of 6-mercaptopurine to inactive metabolites. Patients who have low enzyme activity (or who are homozygous deficient in thiopurine methyltransferase) should not be treated with these agents

Front 5

What are the contraindications to starting anti-TNFalpha therapy?

Back 5

acronym STOIC
Sepsis
Tuberculosis
Optic neuritis (demyelination)
Infusion reaction
Cancer

Front 6

What are the patterns of GIT involvement in Crohn's disease?

Back 6

Approximately 80% small bowel involvement, usually in distal ileum
Approx 50% ileocolitis - involvement of both ileum and colon
Approx 20% have disease limited to the colon
1/3 of pts have perianal disease

Front 7

What are complications associated with Crohn's disease?

Back 7

i) transmural nature of the inflammatory process results in fibrotic strictures. These strictures often lead to repeated episodes of small bowel or less commonly colonic, obstruction.
ii) fistulas
iii) abscess
iv) perianal disease
v) malabsorption

Front 8

What length of terminal ileum must be affected before bile salt malabsorption occurs?

Back 8

50-60cm of terminal ileum diseased or resected

Depletion of the bile salt pool leads to fat malabsorption and steatorrhoea

Front 9

What are the EXTRAINTESTINAL manifestations of Crohn's disease?

Back 9

i) Arthritis - involving primarily large joints
ii) Eye involvement - uveitis, iritis, episcleritis
iii) Skin disorders - erythema nodosum and pyoderma gangrenosum
iv) Primary sclerosing cholangitis
vi) Venous and arterial thromboembolism
vii) Renal stones - can result from steatorrhoea and diarrhoea
viii) Bone loss and osteoporosis - glucocorticoid related and impaired vitamin D and calcium absorption
ix) B12 deficiency

Front 10

What is the typically liver function derangement associated with primary sclerosing cholangitis?

Back 10

Elevation in the serum ALP or GGT

Front 11

What investigations should be requested in a patient suspected of having Crohn's disease?

Back 11

CBC, MBA20, CRP, ESR, Fe studies, B12 - may be normal or reveal anaemia, iron deficiency, elevated WCC, B12 deficiency and/or elevated ESR or CRP

Stool MCS, virology, ova cysts and parasites and CDT

Colonoscopy - cobblestone appearance/ skip lesions (focal ulcerations adjacent to area of normal appearing mucosa

Biopsy of colonic mucosa - focal ulcerations and acute/chronic inflammation. Granulomas MAY be seen in up to 30% of patients. A granuloma does not confirm the diagnosis since they can be present in Yersinia spp. Behcet's disease, TB and lymphoma.

Wireless capsule endoscopy - visualise the small bowel. This should not be performed in patients with stricture since the capsule may become "stuck" and will thus require surgical removal

Front 12

What imaging studies are useful in the diagnosis/ evaluation of Crohn's disease?

Back 12

CT or MRI enterography

MRI for detection of perianal fistulas

Front 13

What serologic markers aid in the diagnosis of IBD?

Back 13

pANCA (anti-neutrophil cytoplasmic antibodies) and anti-Saccharomyces cerevisiae antibodies (ASCA)

2/3 of patients with UC, but only 15-20% of patients with Crohn disease and less than 5% of persons without IBD have pANCA.

By contrast, approximately half of patients with Crohn disease have ASCA, as opposed to less than 5% of patients with UC and control subjects

*Stool markers*
Fecal calprotectin may help identify patients with intestinal inflammation, though it is not routinely done in clinical practice. Presence of faecal calprotectin was 93% sensitive and 96% specific for identifying patients with IBD

Front 14

What is the role of 5-ASA drugs in the management of Crohn's disease?

Back 14

Suggest a trial of oral 5-ASA drugs. The use of 5-ASA drugs for Crohn's disease is controversial. Some data suggest that the use of a 5-ASA drugs may decrease the risk of colon cancer.

For patients with ileitis and mild symptoms, often being Tx with a slow release oral 5-ASA drug, such as Pentasa. Sulfasalazine is less useful for ileitis because colonic bacteria must cleave the drug to release the active 5-ASA moitey.

For patients with ileocolitis or colitis and mild to moderate symptoms, we initiate therapy with sulfsalazine.

We suggest antibiotics in patients who do not tolerate 5-ASAs or do not improve within 3-4 weeks of starting a 5-ASA. it is unclear if the efficacy of antimicrobial therapy is due to treatment of an undetected pathogen, bacterial overgrowth, or an unsuspected microperforation (metronidazole, ciprofloxacin)

Front 15

How is mild to moderate Crohn's disease managed?

Back 15

- 5-ASA drugs
- Antibiotics

Failing the above measures, prednisolone 40-60mg daily should be initiated. A response should be expected within 10-14 days. The dose can then be tapered by 5mg/week with a view to discontinuing prednisolone. Maintenance with a 5-ASA drug should be considered.

Budesonide (non-systemic glucocorticoid) that may be used as an alternative to prednisolone for induction of remission in patients with active ileitis or right sided Crohn colitis.