Evaluating Diagnostic Ultrasound of the Vagus Nerve as a Surrogate Marker for Autonomic Neuropathy in Diabetic Patients

Abstract

Background and Objectives: Diagnostic ultrasound of the vagus nerve has been used to examine different polyneuropathies, and it has been suggested to be useful as a marker of autonomic dysfunction in diabetic patients. Materials and Methods: We analyzed the cross-sectional area (CSA) of the right vagus nerve of 111 patients with type 2 diabetes in comparison to 104 healthy adults and 41 patients with CIDP (chronic inflammatory demyelinating polyneuropathy). In the diabetes group, sympathetic skin response (SSR) was measured as an indicator for autonomic neuropathy. Carotid intima–media thickness (CIMT) was measured as a surrogate for atherosclerosis. Clinical symptoms of polyneuropathy were assessed using the Neuropathy Symptom Score and the Neuropathy Disability Score. Results: In total, 61.3% of the diabetes patients had clinical signs of polyneuropathy; 23.4% had no SSR at the feet as an indicator of autonomic neuropathy. Mean vagus nerve CSA did not differ in patients with and without diabetic polyneuropathy or in diabetic patients with and without SSR at the feet. No significant correlation was found between vagus nerve CSA and CIMT or SSR parameters in diabetic patients. Mean CSA of the right vagus nerve was slightly larger in diabetic patients (p = 0.028) and in patients with CIDP (p = 0.015) than in healthy controls. Conclusions: Effect sizes and mean differences were rather small so that a reliable diagnosis cannot be performed based on the vagus nerve measurement of a single person alone. Vagus nerve CSA seems not suitable as an indicator of autonomic dysfunction or cardiovascular risk in diabetic patients.

Evaluation of Serum Neurofilament Light Chain and Nerve Ultrasound in Diabetic Neuropathy

“…This indicates that more severe and/or chronic DPN results in higher NfL and more atrophic vagus nerves. However, another conducted study, showed that mean vagus nerve CSA did not differ in patients with and without DPN, and that a reliable diagnosis cannot be performed based on the vagus nerve measurement of a single person alone 44 …”

“…However, another conducted study, showed that mean vagus nerve CSA did not differ in patients with and without DPN, and that a reliable diagnosis cannot be performed based on the vagus nerve measurement of a single person alone. 44 Besides studying CSA in DPN, other parameters, such as changes in echogenicity and neural flow have been described, but less frequently. Our study showed predominance of the hypoechoic nerve pattern, with a loss of honeycomb appearance and presence of blurred boundaries along the course of different nerves (P < .05).…”