Ultrasound assessment of sural nerve in Charcot–Marie-Tooth 1A neuropathy

•Ultrasound (US) nerve assessment is increasingly used for characterising nerve morphology in the study of polyneuropathies.•Previous nerve US studies performed on Charcot–Marie-Tooth (CMT) patients showed an increased US pattern at upper limb nerves.•Conversely in most cases the sural nerve had normal cross-sectional area (CSA).

ObjectiveNerve ultrasound (US) has been used to study peripheral nerve disease, and increase of the cross-sectional area (CSA) has been described in demyelinating polyneuropathy. The objective of the current study is to characterise the US features of the sural nerve in a sample of Charcot–Marie-Tooth (CMT) 1A patients.MethodsA total of 20 CMT1A patients were enrolled. As control group we studied 37 age- and sex-matched subjects. All patients underwent clinical examination, neurophysiology and US evaluation of the bilateral sural nerve and right ulnar nerve. US results were correlated with neurophysiology and clinical data.ResultsSural nerve CSA was not increased in the majority of patients (70%), whereas an increased ulnar nerve CSA was present in the whole sample. Inverse relations were found between CSA of the ulnar nerve and body mass index (BMI) (p < 0.0002, R = −0.8) and CSA of the sural nerve and age (right 0.006, R = −0.6, left 0.002, R = −0.6 and left and right p = 0.00003, R = −0.4).ConclusionsUS showed ulnar CSA enlargement and normal sural nerve CSA.SignificanceThe significance of normal sural nerve CSA in CMT1A patients need to be further investigated, possibly through longitudinal studies.