Electrophysiological changes in sensorimotor nerves in diabetes mellitus & usefulness of nerve conduction studies for early diagnosis of diabetic neuropathy

Abstract

Background: Diabetes Mellitus(DM) a metabolic disorder is the most common cause of peripheral neuropathy. Nerve conduction studies(NCS) are commonly employed to detect the neuropathy. The present study was undertaken to find out the utility of NCS as an early indicator of neuropathy in diabetic patients. Materials and methods: Study was carried out in 50 diagnosed DM patients attending OPD in Medicine, Civil Hospital, Ahmedabad. Diabetic subjects were selected having FBS >110 mg/dL with duration of DM > 5 years. Their HbA1c levels were measured for glycaemic control. Diabetic patients with good glycaemic control were grouped in group A and that with poor glycaemic control in group B. 25 age matched non-diabetic and healthy subjects were selected for control group C. NCS was performed at Institute of Spine, Civil Hospital Campus, Ahmedabad. Nerve conduction parameters like compound muscle action potential(CMAP), sensory nerve action potential(SNAP), nerve conduction velocity(NCV) and distal latency(DL) were studied. Results: In our study there is increase in DL of peroneal, sural; median and ulnar sensory nerves in group B subjects. NCV of sensorimotor nerves is significantly decreased in group B subjects. SNAP of all nerves is reduced in group A and B. CMAP is reduced significantly in all nerves in group B. Conclusion: As DM progress further, it increases risk of neuronal involvement which can be accelerated by poor glycaemic control. Our result indicates demyelinating type of neuropathy with some changes of axonopathy. Therefore NCS is done for early detection of neuropathy in DM patients.