[Parenteral replacement of thyroid hormones].

Because of the development in parenteral nutrition, the replacement of thyroid hormones in hypothyroid or athyroid patients under intravenous hyperalimentation has become a new problem to be considered. We tried parenteral replacement of the hormones, intravenously or by enema, in three such patients. Two patients, 54 y-o and 64 y-o females, who underwent laryngo-esophago-thyroidectomy for cervical esophageal cancer or thyroid cancer, had replacement with intravenous l-thyroxine with an initial dose of 100 micrograms/day for 9 and 22 days, respectively. Another patient, a 56 y-o female with dysphagia due to local recurrence of cervical esophageal cancer after laryngo-esophago-thyroidectomy, was given 100 mg of desiccated thyroid by enema for 8 days followed by intravenous l-thyroxine for 104 days. Serum levels of thyroxine, triiodothyronine and TSH before l-thyroxine treatment indicated severe hypothyroidism in all cases. During the first 7 days of the intravenous therapy, serum thyroxine and triiodothyronine levels increased by 0.87 +/- 0.14 microgram/dl/day and 6.7 +/- 4.7 ng/dl/day, respectively, while serum TSH levels decreased by 7.8 +/- 6.4 microU/ml/day. Plasma T4 levels reached the normal level within 7 days, and plasma T3 levels within 11 days, while it took 14 days for plasma TSH levels to decrease to the normal level. The maintenance dose checked by the normal TSH levels in a patient undergoing a long term therapy was 75 micrograms/day or 1.83 micrograms/kg of body weight/day.(ABSTRACT TRUNCATED AT 250 WORDS)