Knowledge Flashcards

Which IBD medication requires testing for TPMT enzyme activity before initiation?

Answer: Azathioprine

TPMT (thiopurine methyltransferase) deficiency increases the risk of severe myelosuppression with azathioprine and 6-mercaptopurine, so testing is required before use.

What is the primary indication for performing a proctocolectomy with ileal pouch-anal anastomosis (IPAA) in UC?

Answer: Medically refractory UC or dysplasia/cancer

IPAA (J-pouch surgery) is the curative procedure for UC, indicated in medically refractory disease, high-grade dysplasia, or colorectal cancer.

Fistula-in-ano associated with Crohn's disease is best initially evaluated by which imaging modality?

Answer: MRI of the pelvis

MRI pelvis is the gold standard for evaluating perianal fistulas in Crohn's disease because it provides superior soft tissue delineation without radiation.

Which cytokine is the primary therapeutic target of ustekinumab?

Answer: IL-12 and IL-23 (shared p40 subunit)

Ustekinumab targets the shared p40 subunit of IL-12 and IL-23, blocking both cytokines involved in Th1 and Th17 inflammatory pathways.

What is the recommended interval for surveillance colonoscopy in a patient who has had extensive UC for 8 years?

Answer: Every 1-2 years

After 8-10 years of extensive UC, annual or biennial surveillance colonoscopy is recommended due to significantly elevated colorectal cancer risk.

Which of the following is a known trigger for flares in IBD patients?

Answer: NSAIDs such as ibuprofen

NSAIDs can disrupt intestinal mucosal integrity and inhibit prostaglandin synthesis, precipitating or worsening IBD flares.

Primary sclerosing cholangitis (PSC) is most frequently associated with which IBD phenotype?

Answer: Ulcerative colitis (pancolitis)

PSC occurs in approximately 2-7% of UC patients, with the strongest association seen in those with extensive or pancolitis phenotype.