Neurologic dysfunction in the idiopathic hypereosinophilic syndrome.

Three specific patterns of neurologic deficit were seen in a group of 52 patients with the idiopathic hypereosinophilic syndrome. Central nervous system dysfunction was seen in 7 patients (15%), 4 of whom had a distinctive encephalopathy characterized by behavioral disturbances and upper motor neuron signs. Peripheral neuropathy was found in 27 patients (52%), with a sensory polyneuropathy the commonest form (in 23 patients), although mononeuritis multiplex and radiculopathy were also seen. Central nervous system abnormalities from embolic disorders were seen in 6 patients (12%). Thus, a total of 65% of these patients had some neurologic dysfunction. Although the spectrum of neurologic disease is broad and includes very different manifestations, we conclude that distinct patterns of neurologic involvement are characteristic of this syndrome.