Pituitary function in children with hydrocephalus before and after the first shunting operation

Abstract

OBJECTIVE: Children with shunted hydrocephalus experience slow linear growth in prepuberty, accelerated pubertal maturation and a reduced final height. A substantial proportion of these patients have a poor growth hormone (GH) response to stimulation and reduced pituitary volume. The basic mechanisms behind these phenomena are still unknown, but one can hypothesize that an unphysiological intracranial pressure (ICP) may be involved. This study was undertaken to investigate the effect of increased ICP on pituitary function. DESIGN: Twenty-one children (nine males) aged 4 months to 15 years were evaluated for pituitary function before and after their first shunting operation. METHODS: A clinical examination was performed, bone age was determined and a combined pituitary stimulation test was performed to evaluate GH, luteinizing hormone, follicle-stimulating hormone, cortisol, thyrotropin and prolactin secretion. RESULTS: GH concentrations were significantly higher 10 and 15 min before the operation (P=0.04 and P=0.03 respectively) than after it. The basal levels of insulin-like growth factor-I (IGF-I) tended to be higher before the operation than afterwards and those of its binding protein-3 (IGFBP-3) were significantly so (P<0.01). CONCLUSIONS: The higher GH response to GH releasing hormone and circulating IGFBP-3 levels in children with hydrocephalus before compared with after their first shunting operation raise the possibility that the reduced GH secretion and retarded linear growth observed in children with shunted hydrocephalus may be a consequence of decreased ICP and/or the lack of physiological pressure variations.