IBD Knowledge 2 — Questions and Answers
Question 1: Which serological marker is most strongly associated with Crohn's disease?
- pANCA
- ASCA (anti-Saccharomyces cerevisiae antibody) (Correct answer)
- Anti-dsDNA
- Anti-CCP
Correct answer: ASCA (anti-Saccharomyces cerevisiae antibody)
ASCA is found in approximately 60-70% of Crohn's disease patients and is a useful distinguishing marker from UC.
Question 2: What is the primary mechanism of action of vedolizumab in IBD treatment?
- TNF-alpha inhibition
- IL-12/23 blockade
- Gut-selective integrin blockade (anti-α4β7) (Correct answer)
- JAK1/2 inhibition
Correct answer: Gut-selective integrin blockade (anti-α4β7)
Vedolizumab selectively blocks α4β7 integrin, preventing lymphocyte trafficking specifically to the gut.
Question 3: Which complication of Crohn's disease is characterized by an abnormal connection between two loops of bowel?
- Stricture
- Abscess
- Entero-enteric fistula (Correct answer)
- Perianal fissure
Correct answer: Entero-enteric fistula
An entero-enteric fistula is an abnormal passage connecting two segments of intestine, a transmural complication characteristic of Crohn's disease.
Question 4: What is the Montreal Classification used to describe in IBD?
- Severity of endoscopic findings
- Extent and behavior of Crohn's disease and extent of UC (Correct answer)
- Response to biologic therapy
- Risk of colorectal cancer
Correct answer: Extent and behavior of Crohn's disease and extent of UC
The Montreal Classification categorizes Crohn's disease by age of onset, location, and behavior, and categorizes UC by extent of involvement.
Question 5: Toxic megacolon is most commonly associated with which condition?
- Crohn's ileitis
- Severe ulcerative colitis (Correct answer)
- Microscopic colitis
- Indeterminate colitis
Correct answer: Severe ulcerative colitis
Toxic megacolon, defined as colonic dilation >6 cm with systemic toxicity, is a life-threatening complication most often seen in severe ulcerative colitis.
Question 6: Which amino salicylate formulation is specifically designed for proximal small bowel Crohn's disease delivery?
- Asacol
- Pentasa (Correct answer)
- Lialda
- Apriso
Correct answer: Pentasa
Pentasa (mesalamine) uses ethylcellulose microgranules that release drug throughout the GI tract from the duodenum onward, making it suitable for small bowel disease.
Question 7: What does the term 'skip lesions' describe in the context of IBD?
- Continuous mucosal inflammation from rectum to colon
- Patchy areas of inflammation separated by normal mucosa in Crohn's disease (Correct answer)
- Superficial ulcers skipping over deep tissue
- Lesions that resolve without treatment
Correct answer: Patchy areas of inflammation separated by normal mucosa in Crohn's disease
Skip lesions refer to discontinuous segments of inflamed bowel interspersed with normal-appearing mucosa, a hallmark endoscopic feature of Crohn's disease.
IBD Knowledge 2
Which serological marker is most strongly associated with Crohn's disease?