Endomyocardial biopsy facilitates diagnosis of eosinophilic granulomatosis with polyangiitis (EGPA): a case report

Background: Eosinophilic granulomatosis with polyangiitis (EGPA) is a rare small vessel leukocytoclastic vasculitis that affects multiple organs and is often associated with anti-neutrophil cytoplasmic antibody (ANCA). EGPA presenting with cardiac involvement is often ANCA-negative, difficult to diagnose, and often fatal. The treatment and prognosis and can be quite different for other conditions included in the differential diagnosis. Imaging modalities have proven unreliable, and the skin is the most commonly biopsied site for histological diagnosis. Case summary: We report a case of a 55-year-old Hispanic man who presented with a non-ST-elevated myocardial infarction, reduced ejection fraction heart failure, and hypereosinophilia. The patient's clinical history also included poorly controlled asthma and sinonasal polyps. Despite ANCA titers within the normal range and a skin biopsy lacking evidence of EPGA, high clinical suspicion prompted an endomyocardial biopsy on day nine from hospital admission which facilitated the diagnosis of ANCA-negative EGPA-induced cardiomyopathy. Six months of follow-up revealed that therapeutic response, as measured by the cardiac ejection fraction, directly correlated with medication compliance. Conclusion: Endomyocardial biopsy aids in the diagnosis of EGPA and initiates use of appropriate therapy.