ABSTRACT
In the adult, the daily needs of thyroid hormones are between 1.5 to 1.7 micro g/kg. In some conditions, these needs can be more important. We report the case of a woman with primary hypothyroidism that necessitated large doses of L-thyroxine. This female patient, age 47, without a family history of thyroid disease, was hospitalized in 1988 because of hypothyroidism [she had no goiter] and iron deficiency anemia. The patient was started on L-thyroxine with a dose of 150 micro g/ day [2.7micro g/kg/day] but the dose had to be increased to 650 micro g/day [12 micro g/kg/day] to obtain clinical and biological euthyroidism [TSH of l.3 microUI/L]. Six years later, while still receiving 650 micro g/day of L-thyroxine, the patient presented with signs of hyperthyroidism with a TSH of 0.01 microUI/L. The doses were progressively decreased to 125 micro g/day [2.3micro g/kg/day] over a five year period and the TSH was back to normal [0.9 micro UI/l] with clinical euthyroidism. This clinical picture is compatible with a syndrome of resistance to the thyroid hormones and the more so because transient forms similar to our case have been reported in the literature