[Primary hypothyroidism as a possible cause of hypertension from long-term follow-up studies of patients with Graves' disease (author's transl)]

Abstract

In order to study the prognosis of Graves' disease, 236 patients, who had been diagnosed as having had Graves' disease more than 10 years before, were examined. Although one patient had died of leukemia and 2 patients had been operated on for breast cancer after 131I therapy, and another 6 patients had died between the ages of 20 and 50, the patients were doing quite well. Generally, the prognosis of Graves' disease is not considered to be serious if the thyroid function is controlled. Among the 72 patients who had been treated with 131I therapy, 15 patients (21%) showed low serum levels of both T3 and T4 and were considered to be suffering from late-onset hypothyroidism. About 67% of the 131I-treated patients were considered to be almost euthyroid, but serum TSH levels were high in half of them, suggesting latent hypothyroidism. The incidence of hypertension seemed to be significantly higher in the TSH-elevated euthyroid group compared with the TSH-nonelevated patients. An excessive reaction of the hypothalamus and/or pituitary gland might have an unfavorable effect not only on the apparent hypothyroidism, but also on the latent hypothyroidism after the therapy for Graves' disease.