Postparathyroidectomy transient thyrotoxicosis

Abstract

Three patients are described who had spontaneously resolving transient thyrotoxicosis after resection of a parathyroid adenoma without thyroidectomy or an apparent thyroid abnormality before or during surgery. All had documented thyrotoxicosis that developed within 2 weeks after surgery, which was clinically symptomatic in two of three patients. The thyrotoxicosis was associated with subnormal radioactive iodine thyroid uptake when performed in the two symptomatic patients and was consistent with a postsurgical inflammatory etiology secondary to thyroid gland trauma during parathyroidectomy. In all patients, the clinical and biochemical evidence of thyrotoxicosis resolved within 2 months. Antithyroglobulin and antimicrosomal antibodies were not detected in the two patients who had a complete recovery 3 months after surgery. However, in the patient who had autoimmune thyroiditis, hyperthyroidism due to Graves' disease subsequently developed 19 months after parathyroidectomy and was associated with increasing titers of antithyroglobulin and antimicrosomal thyroidal autoantibodies. From these observations, we conclude that 1) spontaneously resolving transient thyrotoxicosis of varying severity may occur in some patients after parathyroidectomy, which could be secondary to intraoperative thyroid gland manipulation, and 2) while the occurrence of subsequent Graves' hyperthyroidism in a patient with underlying autoimmune thyroiditis may have been a coincidence, this observation also raises the possibility that thyroidal autoantigen released during parathyroidectomy may trigger the reactivation of autoimmune thyroid disease in a predisposed subject.