Hypereosinophilic syndrome masquerading as a myocardial infarction causing decompensated heart failure

An 81 year old female patient diagnosed with a chronic low grade hypereosinophilic syndrome presented with angina and dyspnoea.

She was managed for a non-ST elevated myocardial infarction since her troponin levels were elevated. On day 5, she suffered an acute clinical deterioration with type I respiratory failure and cardiogenic shock, accompanied by deterioration in left ventricular systolic function demonstrated on echocardiography, and this coincided with a marked rise in eosinophil count. Secondary causes of eosinophilia were excluded permitting a diagnosis of Hypereosinophilic Syndrome (HES) to be made. Coronary angiography revealed unobstructed arteries. Supportive treatment for heart failure included diuretic and inotropes but she dramatically improved both clinically and echocardiographically upon commencement of high dose steroids and hydroxycarbamide. Cardiac magnetic resonance imaging (CMR) demonstrated diffuse, shallow endomyocardial enhancement with late gadolinium, consistent with a diagnosis of eosinophilic myocarditis.

Hypereosinophilic Syndrome can masquerade as a myocardial infarction causing decompensated heart failure. Early recognition and treatment with steroids can improve outcome.