Sural sparing in Guillain-Barré syndrome subtypes: a reappraisal with historical and recent definitions

•Sural sparing is helpful to distinguish Guillain-Barré syndrome subtypes.•Sural sparing as defined historically by an absent median/present sural response is specific of AIDP.•Sural sparing as defined historically is useful irrespective of electrodiagnostic criteria utilized.

ObjectiveTo ascertain the impact of definition and diagnostic criteria on sural sparing in Guillain-Barré syndrome (GBS).MethodsWe retrospectively reviewed records of 78 consecutive patients with GBS from Birmingham, UK (2001-2012) studied within 21 days post-onset. Different criteria were initially used for subtype classification. Sural sparing was subsequently ascertained using historical/recent definitions.ResultsWith Hadden et al.'s criteria, “absent median present sural” and “absent median normal sural” patterns offered sensitivities of 21.7% and 15.2% respectively for AIDP, with specificities of 100% versus axonal GBS. Present sural with two abnormal upper limb responses had a sensitivity of 19.1% and 100% specificity. “Abnormal radial present sural” and “abnormal radial normal sural” patterns had sensitivities of 18.9% and 16.2% and specificity of 100%. With newly-proposed criteria (Rajabally et al., 2015), “absent median present sural” and “absent median normal sural” patterns offered sensitivities of 27.8% and 19.4% respectively, with specificity of 100%. Ulnar patterns were unhelpful with both criteria. Other patterns had suboptimal specificity.ConclusionAlthough of low sensitivity, sural sparing defined by absent median/present sural patterns, is specific of AIDP versus axonal GBS, irrespective of criteria.SignificanceSural sparing is definition and criteria-dependent in GBS but is specific of AIDP with historical definitions, regardless of criteria.