MPO-ANCA–Positive Eosinophilic Granulomatosis with Polyangiitis Presenting as Acute Reversible Cardiomyopathy: A Case Report

Background Eosinophilic granulomatosis with polyangiitis (EGPA) isa rare autoimmune vasculitis characterized by asthma, blood and tissue eosinophilia, and small-vessel vasculitis. It is among the rarest of ANCA-associated vasculitides, and ANCA is present in only 30–40% of patients. ANCA-positive patients have more vasculitic complications, such as mononeuritis multiplex and glomerulonephritis, whereas ANCA-negative patients are more likely to have cardiomyopathy. Case: A 65yearold man with adult-onset asthma presented with acute dyspnea, bronchodilator-resistant wheeze, markedly elevated high-sensitivity troponin (peak 1980 ng/L), peripheral eosinophilia (peak 1550/mm³), and new left ventricular systolic dysfunction (LVEF 30–34%) with normal coronary angiography. He improved rapidly after intravenous corticosteroids; LVEF normalized to 55–60% within six weeks. MPO-ANCA was positive (6.0 U; normal < 0.9). Cardiac MRI and endomyocardial biopsy were not performed because they were unavailable, and the patient had rapid clinical recovery; we document serial labs, imaging, and the diagnostic application of the LATEEAST score to support a presumptive diagnosis of EGPA-related eosinophilic myocarditis. Conclusion The case indicates that MPO-ANCA–positive EGPA can manifest as acute reversible cardiomyopathy without apparent vasculitic manifestations, presumably secondary to eosinophilic myocarditis. When cardiac MRI or biopsy are unavailable, careful integration of clinical features, serial biomarkers, echocardiography, ANCA testing, validated clinical scores, and response to therapy can support a working diagnosis of EGPA-related eosinophilic myocarditis. Early corticosteroid therapy may reverse cardiac dysfunction.