Organ System Pathology USMLE Step 1 Practice Question
A 24-year-old woman presents with a 6-month history of chronic diarrhea, bloating, and progressive fatigue. Vital signs show BP 118/76 mmHg, HR 88/min, RR 16/min, and temperature 37.2°C. She has a pruritic vesicular rash on extensor elbows. Laboratory studies reveal hemoglobin 10.2 g/dL and iron deficiency anemia. Small-bowel biopsy demonstrates villous atrophy, crypt hyperplasia, and increased intraepithelial lymphocytes. Serologic testing for IgA antibodies against tissue transglutaminase is pending. Which antibody is most likely positive?
Answer choices
- AASCA
- BIgA anti-tissue transglutaminaseCorrect answer
- Cp-ANCA
- DAnti-smooth muscle antibody
- EAnti-mitochondrial antibody
- FIgA anti-endomysial antibody as confirmatory serologic marker
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.