Proximal conduction block in the pharyngeal-cervical-brachial variant of Guillain-Barré syndrome.

INTRODUCTION: Conduction block (CB) has been included in the Rajabally criteria for axonal Guillain-Barré syndrome (GBS). Because the nerve roots may be affected early in GBS, detection of proximal CB by the triple stimulation technique (TST) can be useful.

METHODS: We describe TST findings in 2 patients who presented with the pharyngeal-cervical-brachial (PCB) variant of axonal GBS.

RESULTS: In the first patient, although conventional nerve conduction studies (NCS) did not fit electrodiagnostic criteria for axonal GBS, the TST detected proximal CB in the median and ulnar nerves. In the second patient, NCS fulfilled criteria for axonal GBS, and the TST detected proximal CB in the median nerve. After plasmapheresis, NCS and TST findings were normalized, suggesting reversible conduction failure rather than demyelinating CB.

CONCLUSION: The TST may be useful for diagnosis of PCB when NCS remain inconclusive. The technique provides additional clues for classifying PCB into the acute nodo-paranodopathies.