A clinicopathologic correlation of the idiopathic hypereosinophilic syndrome. II. Clinical manifestations.

The idiopathic hypereosinophilic syndrome, a disorder characterized by peripheral blood and bone marrow eosinophilia associated with single or multiple organ system dysfunction attributable to tissue invasion by eosinophils has, in the past, been associated with an extremely poor prognosis. Recently, we reported the favorable impact of a therapeutic protocol consisting of prednisone and/or hydroxyurea on the morbidity and mortality of this syndrome. We have reviewed the clinical and hematologic features upon admission and the subsequent clinical courses of 32 patients with this disease referred to the NIH between 1965 and 1979 in an effort to determine which features suggest a more rapidly progressive course. A grading system based on 22 clinical features involving the 8 organ systems commonly affected by the illness was devised. The disease followed a more aggressive course in patients with evidence of cardiac or neurologic dysfunction at the time of initial NIH evaluation. Although splenomegaly, in and of itself, caused little morbidity, splenic enlargement at presentation appeared to be a predictor of a more aggressive course. The clinical grading system accurately predicted which patients would require no specific antihypereosinophilic therapy, which patients would respond adequately to corticosteroids, and which patients would require therapy with cytotoxic agents. It is proposed that this clinical grading system, and the hematologic grading system outlined in the accompanying report be used as aids in the selection of initial therapy in this group of patients.