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Growth hormone therapy in a poorly growing child with hypophosphatemic rickets
1Department of Pediatrics, Hospital de Clínicas Caracas, Venezuela.
Insights
Growth hormone therapy can significantly improve growth rates and predicted adult height in prepubertal males with hypophosphatemic rickets who show poor growth despite standard treatments. This suggests evaluating growth hormone status in such cases.
Area of Science:
- Pediatric Endocrinology
- Metabolic Bone Disease
Background:
- Hypophosphatemic rickets (HPR) is a rare genetic disorder characterized by impaired phosphate reabsorption, leading to rickets and poor growth.
- Standard treatment involves calcitriol and phosphate supplementation, but some patients exhibit suboptimal growth responses.
Observation:
- A 10-year-old prepubertal male with HPR presented with poor linear growth despite adequate calcitriol and phosphate therapy.
- Exogenous growth hormone (GH) therapy was initiated, despite normal baseline GH testing.
Findings:
- GH treatment led to a substantial increase in growth rate, from 3.9 cm/yr to 9 cm/yr in the initial 4 months, and from 2.7 cm/yr to 6.0 cm/yr over the subsequent 14 months.
- Predicted adult height also improved during the treatment period.
- Minor metabolic changes observed included increased serum phosphorus and decreased 24-hour urine calcium.
Implications:
- Evaluating growth hormone status in children with HPR and poor growth is warranted.
- A trial of growth hormone therapy may be beneficial for select patients with HPR unresponsive to conventional treatment.
Abstract:
We treated a 10 6/12 year old prepubertal male with hypophosphatemic rickets, who was growing poorly despite appropriate treatment with calcitriol and phosphate, with exogenous growth hormone (for an initial trial period of 4 months, followed by 14 months of continuous treatment at a dose of 4 IU three times weekly) even though his growth hormone testing proved to be normal. His growth rate increased significantly during treatment with synthetic growth hormone (from a basal rate of 3.9 cm/yr to 9 cm/yr during the first 4 months of therapy and from 2.7 cm/yr to 6.0 cm/yr during next 14 months of treatment) and his predicted adult height increased as well. Slight metabolic changes were detected in this patient during treatment, with an increase in serum phosphorus and a decrease in twenty-four hour urine calcium concentrations. It would seem reasonable to evaluate the growth hormone status of children with hypophosphatemic rickets who are growing poorly despite appropriate therapy with calcitriol and phosphate and to consider a trial period of therapy with growth hormone in some of them.