Small Bowel Mucosal Disease

• Audio chapter
  Attending-narrated, 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 11.1: NCGS, wheat allergy, and FODMAP framework

  Non-celiac gluten sensitivity, wheat allergy, and FODMAP intolerance share a single clinical surface (bloating, pain, loose stools triggered by wheat-containing foods) but split along three different mechanisms, and the boards expect the candidate to keep them separate because the workup, the labels, and the long-term diet recommendations diverge.

• Section 11.2: Autoimmune enteropathy

  Autoimmune enteropathy is the small bowel autoimmune attack that produces villous atrophy and severe diarrhea unresponsive to gluten withdrawal, and the boards present it as the diagnosis to consider in a patient who looks like celiac disease but does not get better on a gluten-free diet.

• Section 11.3: Whipple disease

  Whipple disease is the systemic infection caused by Tropheryma whipplei, a gram-positive actinomycete that colonizes intestinal macrophages and disseminates from the small bowel to joints, the central nervous system, the heart, and the lymphatic system.

• Section 11.4: Drug-induced enteropathy

  Drug-induced enteropathy is the unifying answer to a vignette in which a patient looks like celiac disease but does not respond to a gluten-free diet, has negative celiac serology, and is taking a medication on the well-known offender list.

• Section 11.5: Immune checkpoint inhibitor enteritis and SIBO

  Immune checkpoint inhibitor enteritis and small intestinal bacterial overgrowth are grouped here because they bracket the small bowel mucosal differential at opposite mechanistic ends.

• Section 11.6: Tropical sprue

  Tropical sprue is the post-infectious enteropathy that follows enteric infection in a tropical region and produces villous atrophy, malabsorption, and combined folate plus B12 deficiency in a returning traveler or long-term resident of an endemic area.

Podcast episodes

1. 01

   Small Bowel Mucosal

   This episode covers what to think about when a biopsy shows enteropathy and celiac has been excluded: the wheat-related symptom syndromes, autoimmune enteropathy, Whipple disease, the drug-induced enteropathies, checkpoint inhibitor enteritis, bacterial overgrowth, and tropical sprue.