Hyperthyroidism with low thyroid hormone

Dr Obuobie and Dr Jones (April 2003 JRSM1) attribute the hyperthyroidism with low serum thyroid hormone concentrations in their patient to suppression of the thyroid hormone concentrations by an infective illness which lasted only one week. It is more likely that this patient had painless thyroiditis. In the days before thyroid hormone concentrations could be measured, the clinical diagnosis of thyrotoxicosis was confirmed by a high uptake of radioactive iodine. Occasionally, the hyperthyroidism was found to be associated with a low uptake. The hyperthyroid phase was due to liberation of thyroid hormones into the blood from the damaged gland. Patients with painless thyroiditis usually became well after a month or so when the thyroid hormones and TSH returned to normal. When the diagnosis of painless thyroiditis was missed, patients ran the risk of receiving antithyroid drugs for as long as one or two years.