Inflammatory Bowel Disease
Both ulcerative colitis and Crohn's disease in one chapter. ASUC through Truelove-Witts and the Oxford day-3 rule, infliximab salvage decisions, biologic positioning across SEQUENCE / SEAVUE / VARSITY, JAK and S1P modulator place in line, IBD pregnancy per PIANO, pouch disease, and CRC surveillance with chromoendoscopy.
- Audio chapterAttending-narrated, listen on the commute.
- ABIM-format MCQs5-option vignettes with full wrong-answer teaching.
- Study guideTables, decision trees, primary sources.
- AI tutorChapter-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 the boards expect the candidate to grade severity 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
- 01
UC Complete
This episode covers ulcerative colitis from classification through full medical management: the UC-versus-Crohn distinction, the Mayo score driving severity-tiered therapy, the acute severe UC script with its salvage rule, mesalamine for mild-to-moderate disease, and the positioning of the biologics and small molecules for steroid-dependent or...
- 02
Crohn Complete
This episode covers Crohn's disease from phenotype through full medical management: the Montreal classification driving risk stratification and the top-down versus step-up choice, Crohn-specific therapy, biologic positioning, and the phenotype-specific algorithms for perianal disease, strictures, and post-operative recurrence.
- 03
Pouch Dysplasia EIM Pregnancy
This episode covers the long-term complications: the pouch and its inflammations, dysplasia surveillance in long-standing colitis, the extraintestinal manifestations, and pregnancy, where continuing biologics through delivery is usually the right call.