Guillain-Barré syndrome (GBS) and its variant, Miller Fisher syndrome (MFS), 
exist as several clinical subtypes with different neurological features and 
presentations. Although the typical clinical features of GBS and MFS are well 
recognized, current classification systems do not comprehensively describe the 
full spectrum of either syndrome. In this Perspectives article, GBS and MFS are 
classified on the basis of current understanding of the common 
pathophysiological profiles of each disease phenotype. GBS is subclassified into 
classic and localized forms (for example, pharyngeal-cervical-brachial weakness 
and bifacial weakness with paraesthesias), and MFS is divided into incomplete 
(for example, acute ophthalmoparesis, acute ataxic neuropathy) and CNS subtypes 
(Bickerstaff brainstem encephalitis). Diagnostic criteria based on clinical 
characteristics are suggested for each condition. We believe this approach to be 
more inclusive than existing systems, and argue that it could facilitate early 
clinical diagnosis and initiation of appropriate immunotherapy.