Myxoedema and thyrotoxicosis: relations between clinical state and concentrations of thyroxine and triiodothyronine in blood.

The clinical manifestations in thyrotoxic and myxoedematous subjects were assessed by clinical diagnostic score indices and related to the free thyroxine index (FT4I) and the free triiodothyronine index (FT3I), basal metabolic rate (BMR) and in the hypothyroid patients to serum thyrotropin (TSH) level. The clinical score index was significantly correlated to both FT4I and FT3I in both groups of patients. No difference existed in degree of correlation between the clinical score index, on the one hand, and FT3I and FT4I, on the other, in either thyrotoxic or myxoedematous subjects. The degree of correlation between clinical score index and FT3I and FT4I was higher than that between the thyroid hormones and BMR. The clinical score index thus appears to be a better indicator of severity of hyper- and hypothyroidism than BMR. Serum TSH concentration was not correlated to the clinical state.