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.

• Section 14.2: UC 5-ASA optimization

  UC treatment is chosen by extent and severity, and it is simplest to take mild to moderate disease first (this section) and then the severe and acute severe disease that escalates beyond it (Section 14.3).

• Section 14.3: 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.

• 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

  Advanced therapy 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).

• Section 14.7: Phenotype-specific Crohn management

  Crohn management is driven by the phenotype because perianal disease, fibrostenotic strictures, and post-operative recurrence each have their own algorithm that does not reduce to "more biologic." Each phenotype has its own algorithm, which is why this section is organized around those three scenarios (pregnancy is covered in Section 14.10 and Ch 35).

• 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.

• 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

   Inflammatory Bowel Disease: Ulcerative Colitis

   Ulcerative colitis care comes down to matching treatment to where the disease sits, how far it reaches, and how sick the patient is. The episode begins with bloody diarrhea, a high fecal calprotectin, and ileocolonoscopy with biopsies that separate ulcerative colitis from Crohn disease, then classifies extent by Montreal. It covers risk factors and the immune biology behind modern drugs. Treatment follows: mesalamine formulation matched to extent, oral plus topical dosing, and sulfasalazine when arthritis coexists. The episode ends in the hospital with admission criteria, the first-hours plan, the day three decision, a single salvage attempt, and the triggers for colectomy.

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2. 02

   Inflammatory Bowel Disease: Crohn Disease Therapy

   Crohn disease is managed by where it sits and how it behaves, because untreated inflammatory disease often scars into strictures or tunnels into fistulas. The episode begins with Montreal classification and the features that justify early biologic therapy, then covers safe thiopurine use and steroid choices. It next sorts advanced drug classes by what they block and which comorbidities exclude them, including JAK inhibitors and S1P modulators. It then takes perianal disease, where the abscess is drained before any biologic, followed by strictures, choosing dilation or surgery, and prevention of postoperative recurrence with scheduled colonoscopy and the Rutgeerts score.

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3. 03

   Inflammatory Bowel Disease: The Pouch and Beyond

   The organizing idea is that where a problem sits, and whether it follows the bowel, decides the treatment. The episode starts with the ileal pouch: pouchitis, its antibiotic-dependent and antibiotic-refractory forms, cuffitis, Crohn-like disease, and irritable pouch, with endoscopy and biopsies first. It then turns to the colon, covering when surveillance starts, how often, which technique, and what to do with visible and invisible dysplasia. Next come extraintestinal manifestations of the joints, eyes, liver, skin, and kidney, sorted by whether they track bowel activity. It closes with the whole patient: nutrient deficiencies, bone health, vaccines before immunosuppression, and pregnancy for both parents.

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Key topics

• ·Fecal calprotectin and IBD diagnosis
• ·Ileocolonoscopy and biopsy findings
• ·Montreal classification of extent
• ·Crohn disease by comparison
• ·Smoking and other risk factors
• ·Immune pathways and IBD genes
• ·Mesalamine formulation and dosing
• ·Sulfasalazine for peripheral arthritis
• ·Severity scoring and Truelove and Witts criteria
• ·Acute severe colitis: steroids, salvage, and surgery
• ·Montreal classification of Crohn disease
• ·Features predicting an aggressive course
• ·Budesonide and systemic steroid use
• ·Thiopurine testing and monitoring
• ·Treat-to-target with objective markers
• ·Advanced therapy classes and exclusions
• ·JAK inhibitors and S1P modulators
• ·Perianal fistula and abscess management
• ·Stricture dilation versus surgery
• ·Postoperative recurrence and Rutgeerts score
• ·Pouchitis causes, risk factors, and diagnosis
• ·Acute, chronic, and refractory pouchitis treatment
• ·Cuffitis, Crohn-like disease, and irritable pouch
• ·Pouch cancer surveillance
• ·Colitis dysplasia surveillance timing and technique
• ·Management of visible and invisible dysplasia
• ·Extraintestinal manifestations and their link to bowel activity
• ·Eye, skin, liver, and kidney complications
• ·Nutrient deficiencies and bone health
• ·Vaccines and pregnancy on immunosuppression