Hyperthyroidism in the elderly.

In 65 elderly hyperthyroid patients (age range 50-78 years), sex differences, signs and symptoms and thyroid function were studied and the data were compared with those on 48 young hyperthyroid patients (age range 20-29 years). The incidence of hyperthyroidism was 3.5 times higher in females than in males among the young patients, whereas it was approximately equal in males and females among the elderly patients. Signs and symptoms conformed with the textbook description in the young subjects but not in the elderly ones. Measurements of serum triiodothyronine (T3) and thyroxine (T4) proved useful in preventing false diagnoses in elderly patients with atypical symptoms. In some elderly subjects with marginal increases of serum T3 and T4 concentrations, measurement of serum thyroid-stimulating hormone (TSH) after administration of thyrotropin-releasing hormone (TRH) was required to achieve an accurate diagnosis. Serum T3 and T4 levels and the thyroidal uptake of radioiodine were slightly but not significantly lower in the elderly than in the young patients. A high titer of circulating thyroid auto-antibody in the elderly may be related to this slight decrease in thyroid function. Serum T3 levels were significantly lower in the elderly than in the young subjects; this suggests impairment of peripheral monodeiodination of T4. Any abnormal serum levels of T4, T3, and TSH before and after administration of TRH could easily be restored to normal by treatment with antithyroid drugs in the elderly patients.