Cryoglobulinemia with encephalopathy: successful treatment by plasma exchange.

A 54-year-old man with essential mixed cryoglobulinemia developed a diffuse and focal encephalopathy while systemic vasculitis was active and serum cryoglobulin was markedly increased. No other cause for his encephalopathy could be determined and the diagnosis of cryoglobulinemic cerebral vasculitis was made. Treatment with plasma exchange, prednisone, and cyclophosphamide resulted in clearing of the encephalopathy and reduction in serum cryoglobulin. The onset of improvement was temporally related to the initiation of plasma exchange. Plasma exchange may have a role in the treatment of other patients with life-threatening immune complex diseases involving the nervous system.