High resolution ultrasound in subclinical diabetic neuropathy: A potential screening tool.

Introduction: Detection of subclinical neuropathy can aid in triage, timely intervention and dedicated care to reduce disease progression and morbidity. High resolution sonography has emerged as a promising technique for evaluation of peripheral nerves. The aim of the present study was to assess the utility of high resolution sonography in screening diabetic patients for subclinical neuropathy.

Methods: A total of 70 adult patients with type 2 diabetes mellitus and 30 controls were enrolled; those with clinical features of neuropathy constituted the diabetic polyneuropathy group and those without symptoms/normal nerve conduction the non-diabetic polyneuropathy group. After institutional ethical committee approval and informed consent, high resolution sonography was performed by two musculoskeletal radiologists. Nerves studied were median (elbow and wrist), ulnar (cubital tunnel and Guyon's canal), common peroneal (fibular head) and posterior tibial nerve (medial malleolus).The size (cross sectional area), shape, echogenicity and morphology of nerve were assessed and compared between the groups.

Results: The mean cross sectional area of all nerves was significantly higher both in diabetic polyneuropathy and non-diabetic polyneuropathy group compared to controls (p value < .001). Common peroneal nerve cross sectional area of 4.5 mm² had the highest sensitivity (93%) and specificity (86%) for detecting nerve changes in the non-diabetic polyneuropathy group. The nerves were more rounded, hypoechoic and had an altered morphology in both study groups.

Conclusion: Presence of sonographic nerve changes in asymptomatic diabetics depicted that morphological alterations in nerves precede clinical symptoms. High resolution sonography detected nerve changes with a good accuracy, and thus, can be a potential screening tool for detection of subclinical diabetic polyneuropathy.