Hypothyroid neuropathy and myopathy: clinical and electrodiagnostic longitudinal findings.

The clinical and electrodiagnostic findings before and during 6 years of therapy are reported in a 59-year-old man with severe hypothyroidism. He had severe sensory neuropathy, carpal and tarsal tunnel syndromes, mild motor neuropathy and moderately severe myopathy. The sensory signs and symptoms disappeared in the 3rd and 4th years of treatment, respectively. Muscle cramps and pain subsided within 2 years, but mild proximal muscle weakness and atrophy persisted. The sensory distal latencies remained slightly prolonged and the electromyographic changes improved. This case shows that thyroid hormone replacement eliminates the neuropathic manifestations of severe hypothyroidism. In contrast, the myopathic features, such as weakness and muscle wasting, may persist despite maintenance of the euthyroid state.