Ultrasound of the peripheral nerves in systemic vasculitic neuropathies

Abstract

IntroductionUltrasound of the peripheral nerves (PNUS) can be used to visualize nerve pathologies in polyneuropathies (PNP). The aim of this study was to investigate, whether PNUS provides additional information in patients with proven systemic vasculitic neuropathies (VN). Material and methodsSystematic ultrasound measurements of several peripheral nerves, the vagal nerve and the 6th cervical nerve root were performed in 14 patients and 22 healthy controls. Nerve conduction studies of the corresponding nerves were undertaken. Finally, the measured results were compared to a study population of demyelinating immune-mediated and axonal neuropathies. ResultsPatients with VN displayed significant smaller amplitudes of compound muscle action potentials (CMAP) (p<0.05) and sensory nerve action potentials (SNAP) compared to healthy controls, while conduction velocity did not differ between groups. The mean nerve cross-sectional areas (CSA) were increased in several peripheral nerves compared to the controls, most prominent in tibial and fibular nerve (p<0.01). PNUS revealed nerve enlargement in most of the clinically and electrophysiologically affected nerves (22 out of 31) in VN. Nerve enlargement was more often seen in vasculitic neuropathies than in other axonal neuropathies, but significantly rarer than in demyelinating neuropathies. ConclusionFocal CSA enlargement in one or more nerves in electrophysiologically axonal neuropathies can be a hint for VN and thus facilitate diagnostic and therapeutic procedures.