SEQUENTIAL STUDY OF THE IMPAIRMENT OF THYROID FUNCTION IN THE EARLY STAGE OF SUBACUTE THYROIDITIS

Abstract

A sequential study of various parameters of thyroid metabolism has been carried out in 2 patients during the weeks following the clinical onset of subacute thyroiditis, the aim being to define the nature and extent of the anomalies of thyroid function. In the early stage, serum thyroxine, protein bound iodine and T₃ resin uptake levels were in the thyrotoxic range. In both cases, the serum thyroxine values further decreased with a half-life of 7 days and reached the hypothyroid range at the 6–7th week. Both ¹³¹I uptake and TSH plasma levels were found to be low and concomitantly rose at the 6–7th week. In one patient the serum thyroglobulin level was strikingly elevated at the beginning and then fell fairly rapidly; however in both patients, the serum thyroglobulin values remained abnormal. The present study confirmed the concept of a sudden release of preformed hormone stores. Furthermore, the following points were evident: a) marked and transient release of thyroglobulin; b) interruption of the secretory activity during at least 7 weeks; c) adequate functioning of the pituitary-thyroid control mechanism and d) partial recovery of the thyroidal iodine uptake at a time when the hormone secretion was still undetectable.