HYPOTHALAMIC-PITUITARY THYROID ABNORMALITIES IN CHILDREN AFTER RENAL-TRANSPLANTATION

Patients with a successful renal transplant may have abnormalities in thyroid function. We evaluated serum thyroid hormone levels, serum thy rotropin (TSH) response to thyrotropin-releasing hormone (TRH), and th e circadian pattern of serum TSH in 18 children aged 6.6-19.4 years (m edian 12.6 years), 4.0 +/- 2.9 years after renal transplantation. In 1 4 children, immunosuppressive therapy included methylprednisone [mean (+/- SD) 0.17 +/- 0.05 mg/kg per day], while in 11 it included deflaza cort (0.32 +/- 0.1 mg/kg per day). Seven children were studied twice, under methylprednisone and again while on deflazacort therapy. Mean to tal and free thyroxine (T4) values were significantly below the mean c ontrol levels (total T4 108.5 +/- 21.5 vs. 118.7 +/- 22.1 nmol/l, P <0 .05 and free T4 14.4 +/- 4.0 vs. 18 +/- 4.9 pmol/l, P <0.001). Morning basal TSH levels were within the normal range. The mean TSH increment after TRH was 4.4 +/- 3.5 mU/l, significantly lower than that of cont rols (10.8 +/- 4.26, P <0.001). Of 7 patients on methylprednisone, 4 h ad nocturnal TSH surges below the normal range (95% confidence limits 47%-300%); this occurred in 3 of 8 patients on deflazacort therapy. Th e TSH response to TRH was correlated with deflazacort dose. Patients o n methylprednisone and deflazacort therapy had similar thyroid alterat ions. Our findings support the hypothesis that after renal transplanta tion some children have hypothalamic-pituitary thyroid abnormalities i n which glucocorticoids may play a significant role.