[Multineuritis in essential hypereosinophilia syndrome].

A 72-old-man with a dramatic weight loss, exhibited a mononeuritis multiplex of subacute onset, and myalgia. There was hypoesthesia and weakness on median and ulnar nerves bilaterally, and weakness on left femoral nerve. Electrodiagnostical studies showed an axonal pattern of neuropathy. There was a considerable hypereosinophilia on blood count without any aetiologia found on exhaustive explorations. The idiopathic hypereosinophilic syndrome with a mononeuritis multiplex was suggested. Histological findings were an acute myelino-axonal degeneration with endoneural oedema, without vasculitis nor eosinophil cell on nerve-biopsy. Dramatic improvement occurred with corticosteroids and immunosuppressive treatment.