Celiac disease
USMLE Step 1Difficulty: easyLast updated:
A 29-year-old woman is evaluated for iron deficiency anemia that has not improved after 6 months of oral iron. She reports bloating and intermittent loose stools. She has autoimmune thyroiditis. Serum IgA level is normal and tissue transglutaminase IgA antibody is strongly positive. Upper endoscopy with duodenal biopsies is performed while she continues a regular diet.
Which of the following findings is most likely on duodenal biopsy?
Answer and explanation
Correct answer: E. Villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes
Refractory iron deficiency, gastrointestinal symptoms, an associated autoimmune disease, and a positive tissue transglutaminase (tTG)-IgA with normal total IgA strongly suggest celiac disease. Gluten triggers an immune response that damages the small-bowel mucosa. The source describes the biopsy findings as lack or shortening of villi (villous atrophy), increased intraepithelial cells, and crypt hyperplasia. These changes are characteristic but not specific, and they resolve on a strict gluten-free diet. The source also notes that tTG-IgA and endomysial IgA have sensitivity and specificity > 90%. Serum IgA should be measured at the same time, because IgA deficiency can cause false-negative results. That is why the normal IgA level matters here. Testing should be done while the patient is still eating gluten.
Each option explained
- A. Lamina propria filled with PAS-positive foamy macrophagesIncorrect. PAS-positive foamy macrophages are the hallmark of Whipple disease.
- B. Transmural inflammation with noncaseating granulomasIncorrect. Transmural inflammation with noncaseating granulomas suggests Crohn disease.
- C. Normal villi with lipid-laden vacuolated enterocytesIncorrect. Lipid-laden enterocytes with normal villi suggest abetalipoproteinemia.
- D. Normal villi with pear-shaped flagellated trophozoites on the surfaceIncorrect. Surface trophozoites with preserved villi suggest giardiasis, which does not cause a positive tTG-IgA.
- E. Villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytesCorrect. Villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis are the characteristic duodenal findings in celiac disease.
Key point
Celiac disease: positive tTG-IgA (check total IgA) and duodenal villous atrophy, crypt hyperplasia, and intraepithelial lymphocytosis.
From the source
“Findings include lack or shortening of villi (villous atrophy), increased intraepithelial cells, and crypt hyperplasia.”