Motor Neuropathy in Hypothyroidism: Clinical and Electrophysiological Findings

Abstract

Background: Hypothyroidism is a clinical condition associated with low levels of thyroid hormones with raised TSH. Peripheral neuropathy may be associated with hypothyroidism which usually develops insidiously over a long period of time due to irregular taking of drugs or lack of thyroid hormone replacement.

Objectives: The present study was done to evaluate the clinical and electro-physiological findings in hypothyroid patients in order to evaluate the neuromuscular dysfunction as well as motor neuropathy.

Method: In this study, 70 subjects with the age range from 20 to 50 years of both sexes were included of whom 40 hypothyroids were taken in study group (B) with the duration of 6 months to 5 years and 30 healthy euthyroid subjects were taken as control (Group A). On the basis of their TSH level, group B was further divided into group B₁ with TSH level <60 MIU /L (less severe) and group B₂ with TSH >60 MIU /L (severe group). The d latency and NCV for motor nerve function were measured by NCV machine in median and ulnar nerve for upper limb and in common peroneal nerve for lower limb. TT₃, TT₄ were measured by RIA and TSH by IRMA method. All these parameters were measured on the day 1 (one) of their first visit. Data were analysed statistically by ANOVA and Z test.

Result: Both TT₃, TT₄ levels were significantly (P<0.01) lower in hypothyroids in comparison to those of control. Diminished or absence of most of the deep tendon reflexes were found in all the hypothyroids. Most of the patients (67.5%) showed significantly higher (P <0.01) motor distal latencies (MDL) with lower (P> 0.001) conduction velocities (MNCV) and all these changes were more marked in group B₂.

Conclusion: So, the study revealed that motor neuropathy may be a consequence of hypothyroidism.

DOI: 10.3329/bsmmuj.v1i1.3692

Key Words: Hypothyroidism; neuropathy; electrophysiology

BSMMU J 2008; 1(1): 15-18