Management of idiopathic growth hormone deficient patients during puberty.

Boys with idiopathic GH deficiency, treated with hGH and entering spontaneous puberty, have an onset of puberty and peak height velocity (PHV) at a late chronological age but normal bone age. PHV occurs at G3 with testicular volumes of 6-12 ml. The size of PHV and the height gain after G2 are similar to those of a normal delayed adolescent. In contrast, idiopathic GH deficient girls have an onset of puberty and PHV nearer to a normal chronological age and at an early bone age. PHV occurs at B2 and its size and the height gain after B2 are similar to those of normal girls. The length of time of pubertal growth is shorter in both GH deficient boys and girls. Very late induction of puberty in idiopathic GH deficient boys results in psychosocial damage and in bodily disproportion. It is suggested that induction of puberty be considered no later than 14.5 years in boys and 13.5 years in girls with the use of low-dose sex steroids. The decision to induce puberty should be taken to avoid psychosocial problems and be independent of proof of associated gonadotrophin deficiency. In GH deficient girls with early puberty, therapies to delay puberty may be considered. There are theoretical grounds for increasing the GH dose given during puberty, but present dose-response studies fail to include controls for important biological variables and are so far inconclusive. Cost-effectiveness is an important consideration. Increasing the frequency of injections probably improves the growth effect for a given dose of GH.