Eosinophilic Myocarditis Presenting as Cardiac Tamponade: A Diagnostic Challenge

Eosinophilic myocarditis (EM) is a rare cause of acute heart failure. It can occur secondary to drug hypersensitivity, autoimmune diseases such as vasculitis, idiopathic hypereosinophilic syndrome (HES) or malignancy, but is often under-recognized and underdiagnosed, being confused with other causes of heart failure. While EM is associated with various clinical symptoms, it is rarely associated with cardiac tamponade that requires urgent pericardiocentesis. Here we describe a patient with EM who presented with cardiac tamponade and decompensated heart failure likely secondary to autoimmune disease.

Learning points: Work-up for hypereosinophilia should include the identification of treatable causes as well as end-organ dysfunction requiring urgent treatment.In patients presenting with acute heart failure and cardiac tamponade of unclear aetiology, eosinophilic myocarditis should be considered whether or not hypereosinophilia is present on presentation.When invoking the diagnosis of eosinophilic myocarditis, extensive efforts should be made to identify primary causes, such as autoimmune conditions including vasculitis.