Neurological manifestations of the hypereosinophilic syndrome (HES).

The hypereosinophilic syndrome (HES) is a rare disease, characterized by a long lasting hypereosinophilia of the blood and the marrow and by the presence of varying internal symptoms and frequent neurological signs. These latter can be as well central: encephalomalacy, organic psycho-syndrome, as peripheral: polyneuropathy or mononeuropathia multiplex, autonomic neuropathy and in rare cases a polymyositis. The disease clinically resembles very to periarteriitis nodosa (PAN). However, the prognosis of HES is far better, especially when early recognized and adequately treated.