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An adult from a temperate climate develops heart failure with peripheral edema, breathlessness, and decreased exercise tolerance. Echocardiographic studies demonstrate that the ventricles are not expanding normally during diastole. Endocardial biopsy demonstrates fibrosis of the endocardium and focal myocardial necrosis in the adjacent myocardium. An eosinophilic infiltrate is prominent in the biopsy, and peripheral blood eosinophilia is also present. Which of the following is the most likely diagnosis?
Options:
A. Alcoholic cardiomyopathy
B. Cardiac amyloidosis
C. Endocardial fibroelastosis
D. Idiopathic subaortic stenosis
E. Loeffler endocarditis
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E is correct
Trouble filling the ventricles indicates the patient has a restrictive cardiomyopathy. The presence of endomyocardial fibrosis with myocyte necrosis and a prominent eosinophilic infiltrate is most characteristic of Loeffler endocarditis. This condition, also
sometimes called endomyocardial fibrosis with hypereosinophilia syndrome, appears to be the result of a direct toxicity to the heart by proteins (eosinophil ribonuclease and eosinophil major basic protein) in eosinophil granules designed to kill large parasites. Why only a few patients with hypereosinophilia develop cardiac disease is unclear. The underlying hypereosinophilia is often idiopathic, although parasites or other causes of hypereosinophilia have occasionally been reported. Death can occur due to heart failure, arrhythmias, or massive emboli (clots form on the damaged endometrium). Formerly, the prognosis was very poor, but early diagnosis (often during investigation of hypereosinophilia) and open-heart surgery to resect the fibrous tissue have markedly improved the prognosis.
Alcoholic cardiomyopathy (choice A) produces a dilated heart.
Severe cardiac amyloidosis (choice B) does produce a restrictive pattern, but the biopsy would show red extracellular deposits.
Endocardial fibroelastosis (choice C) produces a restrictive pattern, but is a disease of young children.
Idiopathic subaortic stenosis (choice D) produce a hypertrophic cardiomyopathy.
