Physiologic-pathologic correlation in Guillain-Barre syndrome in children

Objective: To correlate electrophysiologic patterns with sural nerve pathol ogy in children with Guillain-Barre syndrome (GBS). Background: Based on el ectrophysiologic and pathologic observations, GBS has been divided into dem yelinating and axonal subtypes. The acute motor axonal neuropathy (AMAN) in volves predominantly motor nerve fibers with a physiologic pattern suggesti ng axonal damage, whereas the acute inflammatory demyelinating polyneuropat hy (AIDP) involves both motor and sensory nerve fibers with a physiologic p attern suggesting demyelination, In this study, we sought to confirm these observations by correlating sural nerve pathology with electrophysiologic f indings in GBS patients. Methods: Biopsies of sural nerve from 29 of 50 pro spectively studied GBS patients were obtained, Nerves were examined by ligh t and electron microscopy, and with immunocytochemistry for macrophages, ly mphocytes, and complement activation products. Results: Sural nerves from A MAN patients were normal or had only a few (0.1% to 0.7%) degenerating fibe rs without lymphocytic infiltration or complement activation. One patient w ith reduced sural sensory nerve action potential classified as acute motor sensory axonal neuropathy (AMSAN) had many degenerating fibers (2.3%) in th e sural nerve. All three AIDP patients displayed active demyelination, and in two patients, lymphocytic infiltration and complement activation product s were observed on the abaxonal Schwann cell surface. Conclusion: Classific ation of Guillain-Barre syndrome subtypes based on motor conduction studies correlates closely with pathologic changes seen in sural nerve. In acute m otor axonal neuropathy cases, the sural nerve is almost completely spared p athologically. In acute inflammatory demyelinating polyneuropathy cases, ma crophage-mediated demyelination and lymphocytic infiltration are common in the biopsies of sural nerves.