Neuromuscular status of thyroid diseases: a prospective clinical and electrodiagnostic study

Abstract

With this study, it has been intended to evaluate the neuromuscular symptoms and findings observed in patients with the diagnoses of hyperthyroidism and hypothyroidism. This study included 21 patients with hyperthyroidism, 19 patients with hypothyroidism and a control group comprised of 29 healthy persons. In the patient group with hypothyroidism, the increase in the median motor distal latency and the median sensorial distal latency (p < 0.0001), the reduction in the median sensory action potential amplitude (p < 0.01) and the slowing in the velocity of nerve conduction (p < 0.01) were found significantly different when compared to the control group. H-reflex latencies were determined to be significantly longer bilaterally (p < 0.01). In the patient group with hyperthyroidism, only the reduction in the median sensory action potential amplitude and the prolongation in the distal latency (p < 0.05) were significant. As for the lower extremities, the slowing in the velocity of the nerve conduction of bilateral peroneal (p < 0.0001), the prolongation in the peroneal F-wave latency (p < 0.01), the slowing in the velocity of the nerve conduction of bilateral tibial nerve (p < 0.05), the prolongation in the tibial F-wave latency (p < 0.01), the prolongation in the sural nerve distal latency (p < 0.0001) and the reduction in the sensory action potential amplitude (p < 0.05) were determined to be significantly different compared to the control group. Among the thyroid patients, 17 (42.5%) patients were diagnosed with mononeuropathy and polyneuropathy. Entrapment neuropathy was observed in 30% and diffuse neuropathy in 10% of the patients. Mypopathy findings were observed in 2 patients.