Neurologic complications of thyroid and parathyroid disease.

Common thyroid and parathyroid disorders present with reversible neurologic signs and symptoms affecting the central and peripheral nervous system, musculature, and mental function. Patients with thyrotoxicosis may have myopathy, spasticity, seizures, and multiple psychiatric symptoms. A deficiency of thyroid hormone also causes muscle weakness and may be accompanied by reversible muscle hypertrophy or movement disorders. The chronic hypercalcemia that develops secondary to hyperparathyroidism produces many psychiatric and cognitive symptoms, as well as a reversible myopathy. Calcium deficiency leads to neuromuscular irritability, paresthesias, and tetany. Psychiatric disorders are also common in this disorder.