Diagnosis and management of growth retardation with special reference to the problem of hypopituitarism

Essentials of growth diagnosis

There is more to growth than GH. Growth disorders can be approached expeditiously by assessing the relationships among height, weight, BA and height velocity. Undernutrition is indicated by low weight for height; diabetes mellitus, hyperthyroidism, and electrolyte disturbances are the major endocrine considerations. Short stature results from intrinsically short, delayed, or attenuated growth patterns. Excessive stature results from intrinsically tall, advanced, or accelerated growth patterns. Each of these patterns causing linear growth abnormalities has a distinct differential diagnosis that variously includes endocrine, metabolic, genetic, and systemic disorders.

How necessary is a chromosomal analysis in growth-retarded girls?

In growth-retarded girls, shortness may be the only clinical sign of Turner syndrome. Therefore recommendations have been published that a chromosomal analysis should be carried out in every girl showing growth retardation. The present study was carried out to examine whether the head circumference of small girls can serve as a criterion and hence limit the need for expensive chromosomal analysis. The head circumferences of 45 girls with Turner syndrome were compared with those of 41 growth-retarded girls. It could be shown that the heads of the patients with Turner syndrome had a normal circumference, whereas the heads of the control group were significantly smaller. In view of this result, the risk of overlooking Turner syndrome in diagnosing growth retardation without a chromosomal analysis could be estimated to be 1:9000. The conclusion is drawn that a chromosomal analysis is not necessary in girls whose growth retardation is combined with a small head circumference and who do not show other malformations.

Comparison of dose frequency of human growth hormone in treatment of organic and idiopathic hypopituitarism

Two weekly (biw) injections of pituitary human growth hormone (hGH) were compared with three weekly (tiw) injections of hGH (0.24 IU hGH/kg body weight/wk for both groups) for effect on growth rate in children with idiopathic and organic hypopituitarism. Both dosage schedules resulted in increased growth rate during the first 12 months of therapy; the tiw dosage was more effective in the first 6 months in patients with organic hypopituitarism, and in the second 6 months in patients with idiopathic hypopituitarism. There was no advantage to tiw therapy during the second year of therapy in either group. The additional increment in height after 1 year of therapy using tiw compared with biw therapy was 2 cm and 1 cm for the patients with organic and idiopathic hypopituitarism, respectively. This increment should be weighed against the cost, pain, and inconvenience of tiw versus biw doses of hGH in the treatment of hGH deficiency. With the dosages used in this study, tiw therapy was more effective during the first year, when patients are more responsive, and should be recommended. Twice weekly therapy could be considered for the second and possibly subsequent years of therapy. Other schedules of treatment may be more effective than either of these schedules.

Treatment of growth hormone deficiency

According to the results reported in the literature and from our own experience, the following recommendations for the treatment of children with GHD can be given: In order to start GH replacement therapy in early childhood the diagnosis of GHD should be made as early as possible. The growth hormone dose during prepubertal age should not fall short of 12 IU/m2 per week. During spontaneous or induced puberty, the dose needs to be increased, possibly by a factor of two. Daily subcutaneous injections appear most suitable. Treatment with growth hormone releasing factors in cases with hypothalamic GHD, although a promising alternative to the treatment with hGH (Thorner et al, 1985), must be considered experimental at this point. Thyroxine replacement at a daily dose of 75-100 micrograms/m2 should be given in cases of secondary hypothyroidism. Glucocorticoid replacement, if required, should be given at low doses (e.g. hydrocortisone 10 (to 15) mg/m2 per day in divided doses). In cases with additional gonadotropin deficiency, sex steroids (or anabolic steroids) should be given with frequent monitoring of bone maturity not before the age of 13 in girls or 15 years in boys. In boys depot testosterone starting at low doses (e.g. 50-100 mg/month i.m.) will induce a puberty-like increment in height velocity. Since the effect of oestrogens--even in low doses--on growth is uncertain, their administration before achievement of near-normal adult height should be avoided. With the advancement of diagnostic techniques and with the experience in treatment accumulated over the past 25 years, patients with GHD need no longer become dwarfs.

Long-term response to human growth hormone in 36 children with idiopathic growth hormone deficiency

The results of long term treatment with human growth hormone (Crescormon, 12.4 IU/m2/week) in 36 patients with idiopathic growth hormone deficiency are given. Birth trauma--in particular assisted breech delivery (30%)--is the major aetiological cause. Twelve patients had isolated growth hormone deficiency (IGHD), 24 had multiple pituitary hormone deficiencies (MPHD) of which 19 were treated with additional thyroid hormones. The results were judged by the criteria of height velocity, total height gain and change of height prediction (TW2, age based). It is concluded that the growth hormone dose chosen in many cases is insufficient to maintain high growth rates after the first year of treatment, when "catch-up" no loner takes place. The tendency of patients supplemented with thyroid hormone to grow better--without additional bone-age advancement--calls for careful search for hypothyroidism and suggests the use of thyroxin in cases of doubt.

Phenotypic and genetic analysis of the silver-Russell syndrome

A family is reported in which two half-siblings present clinical findings suggestive of the Silver-Russell syndrome (SRS). The available published literature on SRS is reviewed and the variable expression of the syndrome demonstrated. A review of published pedigrees of the syndrome suggests that in a small percentage of cases, SRS has a genetic etiology.

Insulin secretion in children with growth retardation

The effect of tolbutamide administration on insulin secretion was studied in 69 children with growth retardation. Diminished insulin secretion was found in all the patients, compared to the control group. This insulin deficit was most evident in patients with isolated, total GH deficiency and least evident in children with idiopathic short stature. Intermediate values were found in dwarfism due to isolated, partial GH deficiency. These results favour the hypothesis that hypoinsulinism contributes to the somatotropin deficiency in causing growth retardation.