Anti-tubercular treatments containing Isoniazid (INH) and Type-2 Diabetes Mellitus are independently known to cause peripheral neuropathy (PN). There are multiple mechanisms and biochemical interactions between the two conditions which can lead to a proposed increase in severity among comorbid patients. In this study, we aim to explore the degree of PN induced in patients who have completed eight weeks of INH treatment and whether the presence of Type-2 Diabetes Mellitus has any effect on the extent of PN developed or not.

The study participants were divided into Group A (30 Diabetic patients on INH) and Group B (30 Non-Diabetic patients on INH). We obtained informed consent from the subjects and assessed the nerve conduction parameters of the bilateral median, ulnar, common and superficial peroneal nerves. We analysed the data using an unpaired-T test in SPSS and a p-value of <0.05 was taken to be statistically significant.

The mean motor parameters of bilateral median, ulnar and common peroneal nerves yielded a significant reduction of the distal nerve amplitudes of bilateral median and ulnar nerves, and NCV of bilateral median, ulnar and common personal nerves in Diabetic patients versus Non-diabetics. Results also showed a significant increase in distal latency in median, ulnar and common peroneal nerves in Diabetics. The mean sensory parameters of bilateral median and superficial peroneal nerves demonstrated a significant reduction in amplitudes and NCV of bilateral median and superficial peroneal nerves. Results also showed a significant increase in latency in the right median nerve in Diabetics. 

This study concluded that Group A had more motor alterations of the median, ulnar and common peroneal nerves and more sensory alterations of median and superficial peroneal nerves when compared with Group B.