Reversible Conduction Failure in Chronic Immune-Mediated Sensorimotor and Autonomic Polyneuropathy.

Reversible conduction failure (RCF) has been described in several subtypes of Guillain-Barre syndrome and is typically observed within the first 10 weeks. We describe the presence of RCF lasting for at least 9 months or longer without secondary axonal degeneration in a case of chronic sensorimotor and autonomic polyneuropathy. A 63-year-old woman presented with lower back pain, limb pain, paresthesia, and weakness after a sinus infection. She was diagnosed with mild Guillain-Barre syndrome and treated symptomatically. Four months later, she developed symptoms of dysautonomia and worsening neuropathic pain, and treatment with intravenous immunoglobulin led to significant clinical improvement. Electrodiagnostic study revealed significant improvement, manifesting as increased response amplitudes, improved conduction velocities, shortening of distal latencies, and reduction of sensory and motor response durations without temporal dispersion, thus fitting to the RCF definition. Detection of RCF may have further important implications in the evaluation and management of chronic immune-mediated polyneuropathy.