Three patients with hypothyroidism of 15-48 months' duration developed Graves' disease while on thyroid hormone replacement therapy. In one patient, the hyperthyrold phase was preceded by ophthalmopathy and nonsuppresslble 24-hour radioactive iodine uptake (RAIU). Eventually, all had hyperthyrold findings with elevated thyroid hormone levels, high 24-hour RAIU, and a diffuse uniform uptake of RAI by the enlarged thyroid. All subjects had negative antithyroglobulin and antimicrosomal antibody titers. Two had demonstrable long-acting thyroid stimulator (LATS) in their sera. All three were followed for 5-36 months while on propylthiouracil therapy prior to surgery or RAI administration. Both LATS-positive patients underwent bilateral subtotal thyroidectomy. Classical changes of Graves' disease were found on histopathological examination of resected tissues.
Guansing, A. R.; Klink, D. D.; Engbring, N.; Leung, Y.; Chakravarty, J.; and Wilson, S.
"Graves' Disease Following the Occurrence of Hypothyroidism,"
Henry Ford Hospital Medical Journal
: Vol. 28
Available at: https://scholarlycommons.henryford.com/hfhmedjournal/vol28/iss2/14