Role of peripheral nerve ultrasound in pre-clinical prediction of diabetic neuropathy: Hospital-based cross-sectional study

Abstract

Purpose: Nerve involvement in diabetes is a result of chronic microvascular insult, and it can precede the onset of neurological signs/symptoms in months. Nerve conduction studies (invasive) are the only known lab test to detect neuropathy. Nerve ultrasound can diagnose changes in neuropathy, particularly in peripheral nerves. The study aimed to assess sonography features of the sural nerve in patients with diabetic neuropathy and to determine whether ultrasound of the sural nerve can be used as a screening tool to detect early changes of neuropathy in otherwise asymptomatic known diabetics.

Material and methods: This was a hospital-based cross-sectional observational analytical study. Subjects were recruited by consecutive sampling in three groups based on their diabetic status and symptoms: Diabetic Neuropathic, Diabetic non-neuropathic and Healthy controls. All subjects underwent ultrasound of the sural nerve to assess three parameters: cross-sectional area (CSA), thickness-to-width ratio and maximum fascicle thickness. A nerve conduction study of the sural nerve was done for 2nd group. Data was analysed in SPSS V25, and group findings were compared using multiple analysis methods. P<0.05 was considered statistically significant.

Results: Among three USG parameters, CSA of the sural nerve was found to be the most sensitive and specific for neuropathy. Within the 2nd group, CSA showed a significant difference (p-value 0.02) between individuals with normal and abnormal Nerve conduction study results (sensitivity 86.4%; specificity 54.8% for the cut-off value 2.31mm2).

Conclusion: Sural nerve ultrasound is comparable to nerve conduction studies in detecting precedent neuropathy in otherwise asymptomatic known diabetics.