Evaluation of Neuromuscular Functions in Hashimoto’s Thyroiditis

Abstract

Hashimoto’s thyroiditis is the most prevalent autoimmune thyroid disease with an increasing incidence. Although the exact causes and pathogenesis of Hashimoto’s thyroiditis are not yet fully understood, the literature indicates complex interactions of immunologic, genetic, environmental, and epigenetic factors. It generally leads to hypothyroidism which can cause neuromuscular problems including neuropathy and myopathy. Data on neuromuscular functions of Hashimoto’s thyroiditis patients are relatively underreported and not up to date.The current observational study aimed to evaluate neuromuscular functions and sympathetic skin responses (SSR) in patients with Hashimoto’s thyroiditis and compare them with healthy participants. In total, 50 patients (25 females, 25 males; mean age, 31.6±4.9 years; range: 25-40 years) including 33 euthyroid, 10 with subclinical hypothyroidism, and 7 with hypothyroidism were included. The control group consisted of 50 healthy individuals (25 females, 25 males; mean age: 31.5±5.1 years; range, 25-40 years). Nerve conduction studies, repetitive nerve stimulation, SSRs and F wave recordings were performed in all participants. There were significant differences in the mean SSR latency and amplitude both in the upper extremities (p<0.001 and p=0.013, respectively) and in the lower extremities (p=0.008 and p=0.002, respectively) in the comparison groups. There was a significant difference in comparison groups regarding needle electroneuromyography (EMG) tests (p=0.012) and 14% of the patients showed myogenic EMG findings. In addition, a significant correlation was found between EMG findings and anti-TPO levels in the Hashimoto’s thyroiditis patients (r=0.453; p=0.001). No significant differences were found in the nerve conduction studies, routine EMG tests, repetitive nerve stimulations or F wave recordings between patients and control groups. Hashimoto’s thyroiditis, can cause negative influences on the proper functioning of neuromuscular systems. SSR, and electrophysiological tests may be beneficial for early detection and investigation of neuromuscular abnormalities in these patients.