The Euthyroid Sick Syndrome in Infants with Severe Metabolic Acidosis
The influence of acidosis on peripheral metabolism of T. was studied in infants with 4 diarrhea and metabolic acidosis. The serum concentrations of T4, T3, rT3, TSH and TBG were compared to those of healthy control subjects. Significantly lower T3 and T4 and significantly higher rT3 serum concentrations were found in the patients in contrast to the control group. No significant differences were found in TSH and TBG values between infants with metabolic acidosis and control subjects. Initial pH showed a significant correlation with T3 but not with T4 and rT3. Despite the reduced serum T3 and T4 concentrations, TSH values were within the normal range. Our data show that the metabolic acidosis with normal anion gap could result in the abnormal peripheral conversion of T4 to T3 and the significant reduction of T3 serum levels, all of which are characterized by the low T3 syndrome.