Inflammatory Bowel Disease

• Audio chapter
  Single-voice audio, listen on the commute.
• ABIM-format MCQs
  5-option vignettes with full wrong-answer teaching.
• Study guide
  Tables, decision trees, primary sources.
• AI tutor
  Chapter-grounded, answers the question you're stuck on.

What this chapter covers

• Section 14.1: Epidemiology, genetics, and IBD classification

  Inflammatory bowel disease is a chronic immune-mediated disorder of the intestine in which the mucosal immune response loses tolerance for the luminal microbiota in genetically susceptible hosts, and the boards expect a candidate to keep ulcerative colitis and Crohn disease separate by mechanism, distribution, and the environmental triggers that point opposite directions.

• Section 14.2: UC severity, Mayo score, and acute severe UC

  Severity stratification in ulcerative colitis is what triggers everything downstream, from outpatient escalation to hospitalization to colectomy, and severity must be graded quickly using the Mayo score, the Truelove-Witts criteria, and the Travis (Oxford) day-three rule.

• Section 14.3: UC 5-ASA optimization

  Mesalamine and the broader 5-aminosalicylate family are the foundation of mild to moderate UC treatment, and the boards reward candidates who can match the right formulation to the disease extent and combine oral plus topical therapy in distal disease.

• Section 14.4: Crohn phenotype, Montreal, risk stratification

  Crohn disease is phenotypically heterogeneous, and the Montreal classification organizes the disease so that location and behavior drive therapy intensity.

• Section 14.5: Crohn-specific medical therapy

  The medical therapy of Crohn disease parallels UC for severity escalation but differs in drug selection because of the transmural mechanism, the location heterogeneity, and the limited utility of 5-ASA.

• Section 14.6: Biologics across IBD

  The biologic and small-molecule landscape in IBD has expanded from anti-TNF as the single advanced option to a portfolio that targets distinct mechanisms (gut-selective integrin trafficking, IL-12 and IL-23, JAK signaling, S1P-mediated lymphocyte egress), and the boards expect candidates to know the mechanism, the indications, the screening before initiation, and the safety profile of each class.

• Section 14.7: Phenotype-specific Crohn management

  Crohn management is driven by the phenotype because perianal disease, post-operative recurrence, fibrostenotic strictures, and pregnancy each have their own algorithm that does not reduce to "more biologic." The boards expect candidates to recognize the phenotype and switch into the matching algorithm, which is why this section is organized around the four high-yield phenotype scenarios.

• Section 14.8: Pouchitis, cuffitis, and Crohn-like pouch

  Roughly 20 percent of UC patients require colectomy over a 15-year course, and the restorative procedure of choice in patients without contraindications is total proctocolectomy with ileal pouch-anal anastomosis (IPAA), in which the terminal ileum is folded into a J-shaped reservoir anastomosed to the anal canal.

• Section 14.9: IBD dysplasia and CRC surveillance

  Long-standing colonic IBD raises colorectal cancer risk through chronic inflammation that drives a dysplasia-to-cancer sequence distinct from sporadic CRC, and the boards expect candidates to know when to start surveillance, how to perform it (chromoendoscopy or HD white light with virtual chromoendoscopy), and what to do with each grade and morphology of dysplasia (SCENIC framework).

• Section 14.10: EIM, nutrition, vaccines, pregnancy in IBD

  Inflammatory bowel disease is a multisystem disease, and the patient who comes to clinic with a flare often also has an extraintestinal manifestation, a vaccine gap, a nutritional deficit, or an upcoming pregnancy that the gastroenterologist must address.

Podcast episodes

1. 01

   UC Complete

   Episode one of three on inflammatory bowel disease, covering ulcerative colitis from classification through full medical management. Walks the UC-versus-Crohn distinction, the Mayo score driving severity-tiered therapy, the acute severe UC inpatient script with its day-three salvage rule, mesalamine for mild-to-moderate disease, and mechanism-based positioning of biologics and small molecules. Board-focused framework for choosing therapy by matching drug mechanism to patient phenotype.

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2. 02

   Crohn Complete

   Episode two of the IBD chapter takes Crohn disease from phenotype through complete medical management. It runs the Montreal classification into risk stratification and the top-down versus step-up decision, then walks Crohn-specific induction, immunomodulators, and biologic positioning. It closes with the phenotype-specific algorithms for perianal disease, strictures, and post-operative recurrence.

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3. 03

   Pouch Dysplasia EIM Pregnancy

   The long-arc complications of IBD after induction and maintenance: the ileal pouch and its inflammations, dysplasia surveillance in long-standing colitis, the extraintestinal manifestations, and pregnancy. The unifying board move is that active disease, not active medication, is the threat, so biologics usually continue through delivery. Localization, timing of surveillance, and whether a manifestation tracks bowel activity are what get tested.

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Key topics

• ·UC vs Crohn distinction
• ·Montreal extent classification
• ·Mayo score and severity
• ·Acute severe UC management
• ·Mesalamine formulations and delivery
• ·Biologics and small molecules
• ·JAK and S1P modulators
• ·Mechanism-to-patient drug selection
• ·Montreal classification and phenotype drift
• ·Top-down versus step-up risk stratification
• ·Crohn-specific induction and steroids
• ·Thiopurines and methotrexate
• ·Biologics by mechanism and safety
• ·Perianal Crohn algorithm
• ·Stricturing disease and bowel preservation
• ·Post-operative recurrence and Rutgeerts score
• ·Ileal pouch-anal anastomosis and pouchitis
• ·Cuffitis and the Crohn's-like pouch
• ·Chronic antibiotic-dependent vs refractory pouchitis
• ·Dysplasia surveillance in colitis
• ·Chromoendoscopy and dysplasia management
• ·Extraintestinal manifestations of IBD
• ·Pre-biologic vaccination timing
• ·Pregnancy and biologics in IBD