Small Bowel Mucosal 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 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 have three different mechanisms, and each has its own workup and long-term diet.

• Section 11.2: Autoimmune enteropathy

  Autoimmune enteropathy is the small bowel autoimmune attack that produces villous atrophy and severe diarrhea unresponsive to gluten withdrawal.

• 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

  Suspect drug-induced enteropathy when 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 Disease: Beyond Celiac Disease

   Six patients show the small bowel problems that sit beside celiac disease, and each case asks what must be excluded, which finding decides, and how the mechanism chooses treatment. The episode begins by excluding celiac disease before labeling wheat symptoms as gluten sensitivity, wheat allergy, or FODMAP intolerance. It then reads the medication list in seronegative villous atrophy, with olmesartan as the model, and moves to autoimmune enteropathy and its immunosuppressive treatment. Tropical sprue follows, separated by low folate and low B12, and then Whipple disease, from migratory arthritis to biopsy, lumbar puncture, and brain-penetrating antibiotics. It ends with bacterial overgrowth, its causes, breath testing, and recurrence.

   Read the transcript →

Key topics

• ·Excluding celiac disease with HLA testing
• ·Wheat allergy, gluten sensitivity, and FODMAP intolerance
• ·Low-FODMAP diet in three phases
• ·Drug-induced enteropathy and olmesartan sprue
• ·Autoimmune enteropathy
• ·Tropical sprue
• ·Whipple disease
• ·Small intestinal bacterial overgrowth
• ·Board traps across the chapter