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).
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.
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.
Sensory sural nerve conduction studies may contribute to differential diagnosis of inflammatory and hereditary polyneuropathies.