Persistent multifocal pseudo-conduction blocks in vasculitic neuropathy without antiganglioside antibodies

A woman presented with severe multifocal acute axonal neuropathy due to necrotizing vasculitis. Six years later, electrophysiological examination revealed features suggestive of persistent conduction block (CB) with increased temporal dispersion (ITD) affecting the right median and tibial nerves. A clinical case characterized by multifocal CBs that were observed several years after an initial episode of vasculitic neuropathy was recently reported. The occurrence of CBs paralleled clinical deterioration and was attributed to superimposed antiganglioside antibody-mediated demyelination. In contrast, our patient was clinically stable and did not have antiganglioside antibodies. Nerve conduction studies showed pseudo-CBs rather than true CBs. We suggest that pseudo-CBs with ITD can reveal heterogeneous axonal regeneration as a sequel of a severe multifocal vasculitic neuropathy. This condition should be distinguished from the occurrence of pseudo-CB in the acute phase of vasculitis or from superimposed immune-mediated demyelination. Muscle Nerve 40: 290-293, 2009.