Changes in the peripheral eosinophil count in patients with acute eosinophilic myocarditis

Abstract

In many cases, the diagnosis of eosinophilic myocarditis is suggested by an elevated peripheral blood eosinophil count. However, no detailed studies have been performed on the sequential changes in the initial peripheral blood eosinophil count over the course of the disease. We measured the peripheral blood eosinophil count at the time of presentation in eight patients with eosinophilic myocarditis proven by endomyocardial biopsy and intermittently thereafter. The eosinophil count at the time of onset was <500/mm(3) in four patients, >500/mm(3) but <1,000/mm(3) in three patients, and > or =1,000/mm(3) in one patient. In three of the four patients with an initial eosinophil count of <500/mm(3), an increase to > or =500/mm(3) occurred 7-12 days after the onset. The remaining patient did not develop peripheral eosinophilia. In conclusion, in the early stage of eosinophilic myocarditis, peripheral hypereosinophilia is not present initially in some patients, and may not develop during the course of the illness in a subset of these patients.

Management of a Patient With Eosinophilic Myocarditis and Normal Peripheral Eosinophil Count

“…2 In many cases, the causative agent remains unclear. Myocarditis can certainly be diagnosed using, for example, MRI and if hypereosinophilia is present in peripheral blood count, EM can logically be suspected.…”

“…Myocarditis can certainly be diagnosed using, for example, MRI and if hypereosinophilia is present in peripheral blood count, EM can logically be suspected. 1,2 However, it remains controversial whether therapy should be initiated on the sole basis of cardiac imaging and laboratory values without an EMB. We advocate for an EMB to confirm the diagnosis before proceeding with intensive corticosteroid treatment.…”

A case of eosinophilic myocarditis

“…Other case reports for EM confirmed via endomyocardial biopsy have found varying levels in peripheral eosinophil accounts including normal counts. [7] This further demonstrates the difficulty of this diagnosis and supports the utility of a cardiac biopsy in non-ischemic cases of cardiomyopathy that do not have a clear underlying etiology.…”

Guidelines for Diagnosis and Treatment of Myocarditis (JCS 2009)

“…The timing of the onset of increased eosinophil counts in peripheral blood differs among patients. 29 …”