Empty sella in short children with and without hypothalamic-pituitary abnormalities.

A study was conducted on growth hormone (GH) response to oral clonidine (0.15 mg/m2), GH and cortisol responses to i.m. glucagon (0.1 mg/kg), and glucose response to an oral load of glucose (1.75 g/kg). Measurements were made on the circulating concentrations of free thyroxine (FT4), thyroid stimulating hormone (TSH) and different growth parameters and CT sellar images in 25 GH deficient children (Peak GH response to clonidine and glucagon < 7 ug/ml), 15 growth retarded children (Ht < 5th percentile for age and gender) with sickle cell disease (SCD) and GH deficiency, 30 randomly selected children with normal variant short stature (NVSS) (HtSDS 2SD below the mean for age and gender with normal GH response to stimulation (> 10 ug/ml) and 20 age-matched normal children were evaluated. Out of the 25 children with GH deficiency, five had multiple pituitary hormonal deficiency (GH < TSH and/or ACTH. deficiencies), and 20 had isolated GH deficiency. Empty sella, either complete or partial, was detected in 9 out the 20 children with isolated GH deficiency (45%), 4 out of the 5 children with multiple pituitary deficiency (80%), all the children with SCD and GH deficiency (100%), 3 out of the 30 children with NVSS (10%) and in none of the normal children. The insulin-like growth factor-I (IGF-I) concentrations were significantly lower in the two groups of children with GH deficiency compared to those with NVSS. The height standard deviation scores (HTSDS) were significantly lower and the annual growth velocity was slower in children with idiopathic GH deficiency and empty sella compared to those with NVSS and those with empty sella associated with SCD. The bone age delay (yr) did not differ among the 3 groups of children with short stature. All children with isolated GH deficiency associated with empty sella had normal body mass indices (BMI), while all the children with SCD and empty sella had BMI below the 5th percentile for the corresponding age and gender. None of the children had glucose intolerance. In conclusion, children with growth retardation and abnormal hypothalamic pituitary functions have high incidence of empty sella. However, empty sella is detected in considerable number (10%) of short children with normal hypothalamic pituitary function.

Growth hormone response to clonidine in obese children.

Basal and stimulated serum growth hormone (GH) levels after exercise, insulin induced hypoglycemia (IIH) and oral clonidine were evaluated in 20 (16 M, 4 F) normal statured obese (body mass index greater than or equal to 25 kg/M2) children. Basal serum GH levels (mean +/- SEM, 2.0 +/- 0.38 ng/ml) were not different from basal levels in non-obese children. The mean peak levels were 3.16 +/- 1.17 ng/ml, 2.15 +/- 0.36 ng/ml and 3.15 +/- 1.12 ng/ml (+/- SEM) after exercise, IIH and oral clonidine, respectively. The positive responses (peak level of serum GH greater than 7 ng/ml) were seen in 10% with exercise, in 10% with clonidine and in none with IIH test. These observations suggest that GH response to oral clonidine is subnormal in obese children.

Clonidine suppression test--an evaluation of its diagnostic significance in hypertensive patients.

The Clonidine Suppression Test (CST) was performed in 8 patients with Labile hypertension (Group I), 8 patients with mild and moderate Essential hypertension (Group IIa), 8 patients with severe Essential hypertension (Group IIb) and 6 patients with pheochromocytoma (Group III). The mean plasma catecholamine (CA) levels as estimated by a Spectrofluorimetric method were significantly reduced 3-4 hours after administration of clonidine (5 micrograms/kg) by mouth in Group I, IIa & IIb patients. Plasma norepinephrine levels fell from 1.82 +/- SEM 0.35 ng/ml to 1.03 +/- 0.11 ng/ml (p less than 0.05) in Group I, 1.64 +/- 0.36 ng/ml to 0.88 +/- 0.12 ng/ml (p less than 0.025) in Group IIa, 1.23 +/- 0.16 ng/ml to 0.86 +/- 0.12 ng/ml (p less than 0.005) in Group IIb patients. Plasma epinephrine levels fell from 0.35 +/- 0.06 ng/ml to 0.16 +/- 0.03 ng/ml (p less than 0.05) in Group I, 0.34 +/- 0.04 ng/ml to 0.22 +/- 0.03 ng/ml (p less than 0.01) in Group IIa, 0.33 +/- 0.06 ng/ml to 0.18 +/- 0.03 ng/ml (p less than 0.025) in Group IIb patients. The blood pressure and heart rate showed a similar response. By contrast, in patients with pheochromocytoma, the mean plasma CA levels did not show any significant fall, and even rose during the CST, but, when repeated post-operatively, showed normal suppression. No serious side effects were noticed. We conclude that the CST is a safe and reliable test for the diagnosis of pheochromocytoma.(ABSTRACT TRUNCATED AT 250 WORDS)