Chronic relapsing (dysimmune) polyneuropathy: pathogenesis and treatment.

Chronic relapsing polyneuropathy is a distinct dysschwannian/demyelinating polyneuropathy characterized by usually slow onset, progressive or relapsing-remitting course, elevated cerebrospinal fluid (CSF) protein, marked slowing of nerve conduction velocity, segmental demyelination demonstrable in sural nerve biopsies, and absence of systemic illness or abnormal serum immunoglobulins. The cause of the disorder and the mechanisms underlying its chronicity and relapsing-remitting course are not clear. Immunoglobulin deposition observed in sural nerve biopsies and abnormal immunoglobulin patterns in the "CSF in some cases suggest a dysimmune pathogenesis; thus the term chronic relapsing (dysimmune) polyneuropathy (CRDP) is preferred. The disease is a treatable form of idiopathic polyneuropathy. In our series of 25 patients with CRDP, treatment with high-single-dose daily prednisone, slowly tapered to an alternate-day program, has been very successful in the majority. A low (10 to 20 mg) alternate-day-single-dose program, maintained indefinitely, seems to be required to prevent future recurrences. Evidence is provided that other immunosuppressants (azathioprine, cyclophosphamide, poly-ICLC) and possibly plasmapheresis, alone or in conjunction with corticosteroids, may have a beneficial role in controlling difficult cases of chronic relapsing polyneuropathy.