Peripheral nerve ultrasound in friedreich’s ataxia

Eoin Mulroy, Luciana Pelosi, Purwa Joshi, Ruth Leadbetter, Miriam Rodrigues, Stuart Mossman, Richard Roxburgh; J Neurol Neurosurg Psychiatry 2017;88:e1. doi:10.1136/jnnp-2017-316074.59

The ultrasound finding of enlarged peripheral nerves in FRDA patients points to a structural abnormality at peripheral nerve level. This contrasts with the reduced cross-sectional area seen in the cerebellar ataxia, neuronopathy, vestibular areflexia syndrome (CANVAS) which is thought to be due to a pure sensory ganglionopathy (Pelosi et al, Muscle Nerve 2017, in press). While the specific pathophysiology in FRDA is unknown, nerve enlargement suggests, in agreement with recent neuropathological studies, that axonal loss from dorsal root ganglionopathy is not the sole mechanism underlying sensory neuropathy of FRDA. Myelin and/or stromal abnormality at peripheral nerve level may play a significant role.