HYPEREOSINOPHILIC SYNDROME AND MYOCARDIAL-INFARCTION IN A 15-YEAR-OLD

The hypereosinophilic syndrome (HES) is a rare yet frequently fatal di sorder of unknown etiology characterized by markedly elevated eosinoph il counts and subsequent multiple organ failure due presumably to eosi nophil-derived toxicity. We describe the laboratory and anatomic findi ngs in a 15-year-old female with extraordinarily high circulating leve ls of eosinophil major basic protein (MBP) who sustained a precipitous cardiac death secondary to a massive myocardial infarction. Postmoder n examination showed marked cardiomegaly with extensive recent left ve ntricular infarction. Occlusive thrombosis of small blood vessels was evident in the myocardium, spleen, lungs, and kidneys. Immunofluoresce nt staining showed massive MBP deposition in multiple organ parenchyma including the heart, renal glomeruli, adrenal cortex, bronchioles, an d other visceral organs, suggesting a causal relationship. We hypothes ize on the mechanisms of eosinophil toxicity in HES.