Low serum reverse T3 concentration in burned children: its relationship to nutritional state

The correlation between protein turnover and serum thyroid hormone levels was studied in 10 children, ages 1 to 16 years subsequent to severe burn injuries. In contrast to published studies that have shown depression of triiodothyronine (T3) and elevations of reverse T3 (rT3) in stressed patients, no change was found in the mean level of T3 and a 69% decrease in rT3 compared to healthy controls of similar age. Whole body rates of protein synthesis and breakdown were determined using a [15N]glycine turnover technique. The difference between synthesis and breakdown was negatively correlated with the ratio, rT3/T3 in serum. Thus, in burned children, a decrease in N balance was associated with a rise in rT3/T3 which is qualitatively similar to that observed in fasted individuals or in stressed patients who may be semistarved.