[Retrospective study of 290 cases of hyperthyroidism after 55 years of age without previously documented thyroid disorders].

Previous studies having shown differences in the clinical presentation of hyperthyroidism in the young and in the over sixty-years old patients, we studied the presentation of hyperthyroidism of late onset without previous thyroid disorder to determine if it continued to change with age after 55 years. Two hundred and ninety cases of hyperthyroidism presenting after the age of 55 years without a previous history of goitre, collected in the Department of Nuclear Medicine of the Pitié Hospital between January 1976 and May 1980, were analysed retrospectively. There was no significant correlation between age and heart rate or total circulating thyroxine (T4) and triiodothyronine (T3) concentration. A positive correlation with weight loss and a negative correlation with I 131 fixation were observed. It was higher in cases of atrial fibrillation and hyperthyroidism with normal thyroid scintigraphy. Graves' disease with goitre was associated with the most overt signs of thyrotoxicosis and the highest hormonal concentrations, contrarily to toxic adenoma. The T3 but not T4 concentration correlated positively with heart rate. T3 and T4 were positively correlated with weight loss, and this correlation remained significant at constant T4 and T3 concentrations.