Gastroenterology Flashcards
What does the term “extensive colitis” refer to in Ulcerative colitis?
Disease extending proximal to splenic flexure
What part of the GIT do Crohn’s Disease and UC affect respectively?
Crohn’s -> anywhere from mouth to anus. Transmural inflammation with skip lesions
UC -> involves colon, and rectum is almost always involved. Inflammation limited to mucosa
What biomarker is associated with UC?
pANCA
What biomarker is associated with Crohn’s Disease?
ASCA - anti Saccharomyces cerevisiae Ab
What is the peak age of onset of IBD?
20 - 30 years
What relationship does smoking have with Crohn’s and UC?
Crohn’s -> risk factor
UC -> decreases risk
What gene has been identified in ~40% of Crohn’s and is associated with more severe disease?
NOD2
What percentage of UC patients will end up proceeding to colectomy during the course of their disease?
20%
What percentage of Crohn’s patients end up requiring surgical resection?
50%
Which form of IBD is more associated with colorectal cancer?
UC
What is the colorectal cancer screening program for IBD patients?
Commence after 8 years of disease in UC or Crohn’s which involved >1/3 of colon
- annually for active disease / FHx at age <50 / PSC / stricture / previous dysplasia
- 3 yearly otherwise
- 5 yearly if last two scopes normal
What is the main predictor at diagnosis of severe disease in Crohn’s ?
Name 3 other important predictors
Perianal disease
Requiring steroids at diagnosis
LOW >5kg
Fibro-stenosing disease
What are two laboratory markers used for monitoring disease activity in IBD?
CRP (aim <3)
Faecal calprotectin (aim <150)
What is the treatment goal for patients with IBD?
To achieve remission with complete mucosal healing
What is the first line treatment for mild-moderate UC left-sided/extensive colitis?
Oral + topical 5-ASA agent
What is the indication for immunomodulator therapy in UC?
Non-response to initial therapy with oral 5-ASA + steroid, or requiring more than one course of steroids in the year
What is the steroid regime typically used for induction in mild-moderate IBD?
Prednisolone 40mg for 1-2 weeks, slowly tapered over 6-8 weeks
What is the role of TPMT in thiopurine metabolism?
What happens in high TMPT activity?
What happens in low activity?
TMPT catalyses methylation of 6-MP to the inactive 6-MMP. Xanthine oxidase then catalyses 6-MP to the inactive 6-thiouracil
15% of all patients have high TPMT activity (shunters) → high 6-MMP → hepatotoxicity. Can use allopurinol in this setting.
Heterozygous mutation (11%) → low activity Homozygous mutation (0.3%) → negligible activity → very high 6-TG → BM suppression
Which malignancies occur at increased rates with thiopurine use?
Lymphoma
Non-melanoma skin cancer
What is the first line treatment for rectal UC?
Topical + PO 5-ASA
What is the first line treatment for UC limited to proctitis?
Topical + PO 5-ASA (more effective than topical alone)
In Australia, what is the typical 1st line approach for induction in moderate to severe Crohn’s ?
Steroids + immunomodulator
Steroids - if severe then parenteral with hydrocort or methylpred
Immunomodulator - thiopurine or methotrexate
Which patient group in Crohn’s is budesonide preferred for, over prednisolone?
Mild ileocaecal disease
What is the route of escalation for a patient with Crohn’s who has failure of induction with first line therapy?
When is this change made?
Add on a biologic agent =
- TNF inhibitor (infliximab IV / adalimumab SC
- Alpha4beta7 integrin inhibitor (vedolizumab IV)
After 3 months of 1st line therapy