A physician-validated, board-style question from the Active Transport QBank. Try it, then check the reasoning for every option.
An 8-year-old boy who recently immigrated to the United States presents with a rash. Past medical history is significant for a recent sore throat which caused him to miss several days at school. The patient’s vaccination status is unknown. On physical examination, the patient is pale and ill-looking. There are pink rings present on the torso and inner surfaces of the limbs. Cardiac exam is significant for a holosystolic murmur heard best over the apex of the heart. Which of the following histopathologic findings is most likely associated with this patient’s condition?
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A
Atypical lymphocytes on peripheral blood smearIncorrect. Atypical lymphocytes characterize infectious mononucleosis (EBV/CMV), not acute rheumatic fever.
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B
Starry sky appearanceIncorrect. "Starry sky" appearance is the histopathologic signature of Burkitt lymphoma — not rheumatic carditis.
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C
Needle-shaped, negatively birefringent crystal depositsIncorrect. Negatively birefringent needle-shaped crystals are monosodium urate in gout — unrelated to acute rheumatic fever.
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D
Granulomas with giant cellsCorrect. Aschoff bodies — granulomatous foci with central fibrinoid necrosis surrounded by Anitschkow cells and multinucleated giant cells — are the pathognomonic myocardial lesion of acute rheumatic fever.
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E
Change lisinopril to hydrochlorothiazideIncorrect. Thiazides treat hypertension but lack the renoprotective benefit of ACE inhibitors/ARBs in diabetes; switching to an ARB (losartan) preserves the renoprotective effect while eliminating the bradykinin-mediated cough.
↑ Tap an answer to reveal the reasoning
Answer: D. A child with a recent untreated sore throat (presumably group A streptococcal pharyngitis), pink ring-shaped skin lesions (erythema marginatum) on the trunk and inner limbs, and a holosystolic apical murmur (mitral regurgitation) has acute rheumatic fever (ARF). The diagnosis is supported by the Jones criteria (carditis + erythema marginatum here, plus recent strep throat). ARF arises from molecular mimicry between streptococcal M protein and human cardiac/joint/CNS antigens.
The pathognomonic histologic lesion of rheumatic carditis is the Aschoff body — a granulomatous focus in the myocardium consisting of central fibrinoid necrosis surrounded by Anitschkow cells (reactive macrophages with "caterpillar" or "owl-eye" nuclei) and multinucleated Aschoff giant cells. Granulomas with giant cells best describes this lesion.
Distractors: Atypical lymphocytes on smear are seen in infectious mononucleosis (EBV) and other viral infections, not ARF. "Starry sky" appearance is the histologic hallmark of Burkitt lymphoma (tingible-body macrophages amid sheets of lymphoblasts). Needle-shaped, negatively birefringent crystals describe monosodium urate (gout) — totally unrelated to ARF.
Pearl: ARF lesions to know — Aschoff bodies (myocardium) and verrucous valvulitis (mitral valve sterile vegetations).
**Why each option:**
**A.** Atypical lymphocytes characterize infectious mononucleosis (EBV/CMV), not acute rheumatic fever.
**B.** "Starry sky" appearance is the histopathologic signature of Burkitt lymphoma — not rheumatic carditis.
**C.** Negatively birefringent needle-shaped crystals are monosodium urate in gout — unrelated to acute rheumatic fever.
**D.** Correct. Aschoff bodies — granulomatous foci with central fibrinoid necrosis surrounded by Anitschkow cells and multinucleated giant cells — are the pathognomonic myocardial lesion of acute rheumatic fever.