ABSTRACT
The findings in this study suggest that there is defect in the neuromuscular transmission in hyperthyroidism. This abnormality was detected in 62 per cent of the patients and did not directly correlate with proximal muscle weakness present in most of the patients. It seems that the weakness in hyperthyroidism is the result of myopathy as well as neuromuscular transmission both of which might be due to the same metabolic derangement but are not directly related. After treatment, the muscle power became normal in all of the patients and the neuromuscular transmission was normalized in most but not all of them. It is possible that this transmission defect may be due to other mechanisms apart from the hormonal disorder e.g. the same processes as that which occurs in myasthenia gravis. The underlying pathophysiology is worth further exploration.