Sural sensory nerve conduction studies in demyelinating polyneuropathies

Abstract

Objective To examine the pathophysiological state of sensory nerve conduction studies in different types of demyelinating polyneuropathies. Methods A total 16 Acute Inflammatory Demyelinating Polyneuropathy (AIDP), 12 Chronic Inflammatory Demyelinating Polyneuropathy (CIDP) and 7 Hereditary Motor Sensory Neuropathy (HMSN) Type 1 patients were included prospectively. In all patients, bilateral sural nerves were examined with near nerve technique. The pathophysiological states of the sensory nerves were described as normal, demyelinating, axonal or neuropathic using ESTEEM criteria (Tankisi et al., 2005). Result In 16 AIDP patients, sural nerve was normal in 8, demyelinating in 2 and axonal in 6 while, in 12 CIDP patients sural nerve was normal in 4, demyelinating in 2, axonal in 5 and neuropathic in 1. In AIDP and CIDP patients with demyelinating sensory nerves, an atypical disease course with poor response to therapy was observed. In all 7 HMSN Type 1 patients, sural nerves were demyelinating. Conclusion In inflammatory demyelinating polyneuropathies sural nerve is mostly axonal, however demyelinating sensory sural nerves may indicate subtypes. Sensory nerves are always demyelinating in HSMN Type 1 which may help in differential diagnosis. Key message Sensory sural nerve conduction studies may contribute to differential diagnosis of inflammatory and hereditary polyneuropathies.