Pituitary size and function in children and adolescents with shunted hydrocephalus.

OBJECTIVE

Most previous reports of endocrine disorders in children with shunted hydrocephalus have been case reports and there is a lack of systematic information on pituitary anatomy and function among these children. We have obtained these data in a large group of individuals with shunted hydrocephalus.

DESIGN

A controlled cross-sectional study.

PATIENTS

Fifty-four children and adolescents with shunted hydrocephalus were studied for pituitary anatomy and function. They had 54 age- and sex-matched controls (group I). The mean age of the patients and controls was 12.6 years and the mean shunting period 10.6 years. There was a second control group (II) for the magnetic resonance imaging (MRI) and a third control group (III) for the radiography of the sella turcica.

MEASUREMENTS

The anatomy was visualized by MRI of the pituitary gland and by radiography of the sella turcica. The functional evaluation included an arginine-insulin test and a combined stimulation test with corticotrophin releasing factor (CRF), GnRH and TRH.

RESULTS

The patients 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 control group I (20.6 kg/m2 vs 18.0 kg/m2, P < 0.001). They had also a greater 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 mU/l) in the arginine-insulin test. Pituitary height was significantly lower among these patients than in those with a normal response (4.7 mm vs 6.3 mm, P < 0.01), who had an increased pituitary height compared to controls II (5.1 mm, P < 0.01). The area under the curve (AUC) for GH correlated with the pituitary volume (r = 0.50, P < 0.001). The patients had higher basal FSH and LH concentrations than controls I (P < 0.001). The peak to basal ratios of FSH and LH were increased in the prepubertal 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 children with shunted hydrocephalus have an increased pituitary size on average. About one-third of these patients had signs of reduced GH secretion and significantly lower pituitary height, which probably contributes to their poor linear growth. Increased pituitary size was associated with enhanced gonadotrophin secretion, which may result in early puberty in children with shunted hydrocephalus.