Non-demyelinating, reversible conduction failure in a case of pharyngeal-cervical-brachial weakness overlapped by Fisher syndrome

Pathophysiologically, Guillain-Barré syndrome is divided into demyelinating and axonal subtypes. Recent studies have shown that serial nerve conduction studies (NCSs) are required to differentiate a demyelination-remyelination pathophysiology from one with axonal nodal reversible conduction failure. Cases with an overlap of pharyngeal-cervical-brachial weakness and Fisher syndrome (PCB/FS) are uncommon; the NCS findings of such cases have not been well described and the evolution of the NCS findings has not been previously studied. We describe the clinical features and serial NCS findings of a patient with PCB/FS. The evolution of abnormalities in NCS reflected a clinical pattern of weakness that progressed from the top of the body and descended toward the legs, and terminated before reaching the legs. The amplitudes of motor and sensory potentials were decreased, as is consistent with acute motor-sensory axonal neuropathy. However, the amplitudes recovered without the appearance of dispersed potentials seen in remyelination, implicating the pathophysiology of nodal reversible conduction failure. Together with the electrophysiological evidence of the pathophysiology of nodal reversible conduction failure in previously reported PCB patients and FS patients, our case suggests that PCB, FS and PCB/FS fall in a continuous spectrum with axonal GBS subtypes.