Unilateral seizures in a patient with hairy cell leukemia treated with interferon

A patient is described who developed unilateral seizures whilst being treated with recombinant interferon for hairy cell leukemia. Special features included the relatively low dose of interferon, the focal aspect of the epilepsy and the high resistance to anticonvulsants. Oligoclonal banding of cerebrospinal fluid proteins may have resulted from polyclonal activation of bone marrow plasma cells during interferon treatment. Disturbances of consciousness, dysphasia, visual hallucinations, upper motor neuron deficit, tremor, dizziness, numbness, myalgia and headache, all of them neurological complications of interferon treatment, are discussed.