[Rapid improvement of nerve conduction in a patient with chronic inflammatory demyelinating polyradiculoneuropathy...

A patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) underwent electrophysiological examinations before and three days after high-dose intravenous gamma-globulin therapy. In only three days, the distal latency and MCV of the right median nerve were markedly improved without change of amplitude or configuration of CMAP. Such rapid improvement in conduction velocity might not be due to remyelination, because it occurred in only three days. During recovery from conduction block after lidocaine administration in normal subjects, the distal latency was shortened without the change of its amplitude and configuration. This phenomenon is similar to the improvement in the distal latency of the right median nerve of this patient after high-dose intravenous gamma-globulin therapy. We assume, therefore, that the conduction slowing in CIDP should be attributed to inactivation of sodium channels as well as demyelination.