Endocrinologic evaluation of children who grow poorly following renal transplantation.

Some children do not grow well following successful renal transplantation. We reviewed 25 children with renal allografts who receive regular medical care in the renal transplant program at The Children's Hospital, were less than or equal to 18 years of age, and had stable renal function. We compared children who were growing well (n = 14) with those who were growing poorly (n = 11). The children with poor growth more frequently had elevated serum creatinine concentrations (8/11 vs. 3/14). The mean age at transplantation was the same, although the duration of follow-up was shorter for the children growing well (3.3 +/- 0.5 years) than for those growing poorly (6.2 +/- 1.0 years, P less than 0.02). Eight of the children who were growing poorly underwent endocrinologic evaluation. Plasma growth hormone (GH) concentrations were measured during sleep, after arginine and L-DOPA administration, and during a 4-hr oral glucose tolerance test. In 4 patients, the maximum GH concentration was inadequate both following pharmacologic stimulation (4.0 +/- 2.6 ng/ml, n = 4) and during sleep (4.4 +/- 0.2 ng/ml, n = 3). In 2 additional patients, maximal GH concentrations were subnormal during sleep despite adequate responses during pharmacologic stimulation. In the final two patients, GH secretion was adequate both during sleep and after stimulation. All children studied had some degree of renal insufficiency with a mean creatinine clearance of 39 +/- 4 ml/min/1.73 m2. Plasma concentrations of thyroxine, thyrotropin, and IGF-I were normal for age in all eight patients. We conclude that abnormalities in GH secretion occur frequently among patients who grow poorly following successful renal transplantation. Evaluation of GH secretion may be useful in evaluating growth failure in this group of patients, and the usefulness of GH therapy should be investigated.