PITUITARY SIZE AND FUNCTION IN CHILDREN AND ADOLESCENTS WITH SHUNTED HYDROCEPHALUS

OBJECTIVE Most previous reports of endocrine disorders in children wit h shunted hydrocephalus have been case reports and there is a lack of systematic information on pituitary anatomy and function among these c hildren, We have obtained these data in a large group of individuals w ith shunted hydrocephalus. DESIGN A controlled cross-sectional study, PATIENTS Fifty-four children and adolescents with shunted hydrocephalu s were studied for pituitary anatomy and function, They had 54 age- an d sex-matched controls (group I). The mean age of the patients and con trols was 12.6 years and the mean shunting period 10.6 years. There wa s a second control group (II) for the magnetic resonance imaging (MRI) and a third control group (III) for the radiography of the sella turc ica. MEASUREMENTS The anatomy was visualized by MRI of the pituitary g land and by radiography of the sella turcica. The functional evaluatio n included an arginine-insulin test and a combined stimulation test wi th corticotrophin releasing factor (CRF), GnRH and TRH. RESULTS The pa tients were shorter (height 148.4 cm vs 153.7 cm, P<0.05 and relative height -0.5 SDS vs 0.4 SDS, P<0.05) and had a higher BMI than the cont rol group I (20.6 kg/m(2) vs 18.0 kg/m(2), P<0.001). They had also a g reater pituitary height than the control group II (5.8 mm vs 5.1 mm, P <0.01). The patients had significantly lower basal GH levels (P<0.001) than controls I. Sixteen patients (30%) had a poor GH response (<20 m U/I) in the arginine-insulin test. Pituitary height was significantly lower among these patients than in those with a normal response (4.7 m m vs 6.3 mm, P<0.01), who had an increased pituitary height compared t o controls II (5.1 mm, P<0.01). The area under the curve (AUG) for GH correlated with the pituitary volume (r=0.50, P<0.001), The patients h ad higher basal FSH and LH concentrations than controls I (P<0.001). T he peak to basal ratios of FSH and LH were increased in the prepuberta l patients and that of LH at Tanner pubertal stage II in the females, The basal FSH and LH levels correlated with the pituitary volume (r=0. 50 and r=0.54, P<0.001 for), as did FSH AUC and LH AUC (r=0.48 and r=0 .75, P<0.001 for both). CONCLUSIONS These observations indicate that c hildren with shunted hydrocephalus have an increased pituitary size on average. About one-third of these patients had signs of reduced GH se cretion and significantly lower pituitary height, which probably contr ibutes to their poor linear growth, Increased pituitary size was assoc iated with enhanced gonadotrophin secretion, which may result in early puberty in children with shunted hydrocephalus.