Seizures in Hyperthyroidism

7/03/02

Question: How frequently do seizures secondary to hyperthyroidism occur?

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Unique Identifier:8419721

Authors: Tonner DR. Schlechte JA.

Institution: Department of Internal Medicine, University of Iowa Hospitals and Clinics, Iowa City.

Title: Neurologic complications of thyroid and parathyroid disease. [Review] [83 refs]

Source: Medical Clinics of North America. 77(1):251-63, 1993 Jan.

Abstract: 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. [References: 83]

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Unique Identifier:3336793

Authors: Scott TF.

Title: Thyrotoxicosis and seizures.

Source: Southern Medical Journal. 81(1):103, 1988 Jan.

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Unique Identifier:6766396

Authors: Jabbari B. Huott AD.

Title: Seizures in thyrotoxicosis.

Source: Epilepsia. 21(1):91-6, 1980 Feb.

Abstract: Over a period of 2 years we have observed 3 thyrotoxic patients who presented with a convulsive encephalopathy. These patients had no history of seizures before and experienced no further seizures after subsidence of the thyroid dysfunction. During the convulsive period, electroencephalograms of 2 patients showed evidence of cerebral hyperexcitability, but in both cases it returned to normal once the thyroid disorder was corrected. We believe that thyrotoxic seizures are not rare. These seizures can be focal as well as generalized and can constitute the presenting symptoms of the disease. Absence of other laboratory abnormalities such as serum electrolytes, or osmolality changes, or hypoglycemia in all patients who reportedly suffered from thyrotoxic seizures, and the data obtained from animal studies, suggest that human thyrotoxic seizures result mainly from the direct effect of thyroid hormones over the cerebral tissue. CAS Registry/EC Number 6893-02-3 (Triiodothyronine). 7488-70-2 (Thyroxine).