Thyroid Function Tests in Elderly Hyperthyroid Patients

Abstract

Several tests of thyroid function were performed in 35 hyperthyroid patients over the age of 65 (elderly). The results were compared to those of similar tests in 48 hyperthyroid patients under the age of 65 (young). Total serum thyroxine (T4) was within the normal range in 14 percent of the elderly and 11 percent of the young hyperthyroid patients. The free thyroxine index (FTI) was within the normal range in 11 percent of both groups. The triiodothyronine uptake (T3U) proved to be a poor test in both groups. Although elevation of the triiodothyronine (T3) level allowed a diagnosis of "T3-toxicosis" in 2 elderly and 3 young hyperthyroid patients, the T3 level was normal in 34 percent of the elderly and 13 percent of the young subjects. Correction of the T3 range for age reduced the number of normal T3 values to 12.5 percent in the elderly hyperthyroid patients. The 24-hour uptake of radioactive iodine was normal in 12 percent of the young hyperthyroid patients, 27 percent of the elderly patients with Graves' disease, and 70 percent of the elderly patients with toxic nodular goiter, despite recent readjustment of the normal range for the test. It is concluded that the diagnosis of hyperthyroidism in the elderly may be difficult and that no single test can be relied upon to exclude the diagnosis.

Association between lithium use and thyrotoxicosis caused by silent thyroiditis

“…We might have missed some partially treated or mild Graves' disease cases by excluding some patients with normal radioiodine uptakes. However, 88% of patients with Graves' hyperthyroidism under age 65 have elevated radioiodine uptakes (Caplan et al ., 1978). Moreover, hyperthyroidism in Graves' is usually longer lasting and more severe than that in silent thyroiditis.…”

Serum Concentrations of the Iodothyronines in Elderly Subjects: Decreased Triiodothyronine (T3) and Free T3 Index

“…In a previous study (34), we performed several tests of thyroid function in 35 hyperthyroid patients over the age of 65 (elderly) and 48 patients under the age of 65 (young). The T 3 concentration was “normal” in 34 percent of the elderly patients and in 13 percent of the young hyperthyroid patients.…”

Thyrotoxicosis in Institutionalized Elderly Patients With Atrial Fibrillation

“…This strategy may have under¬ estimated the true number of older persons with thyrotox¬ icosis because individuals with subclinical disease may have normal values on thyroid screening tests. 18 Nonetheless, because these tests are currently used in clinical practice to determine thyroid status, we thought that our conservative approach was justified for purposes of this study.…”