Empty sella in children and adolescents with possible hypothalamic-pituitary disorders.

Several computed tomographic scan studies have described empty sellae in children with hypothalamic-pituitary disorders. Magnetic resonance imaging, however, is a more precise technique for visualizing the intrasellar content, such as the stalk and pituitary lobes. Using magnetic resonance imaging, we studied 339 children and adolescents (mean age +/- SD, 12.7 +/- 4.5 yr) with possible hypothalamic-pituitary disorders to ascertain the frequency of primary empty sella and examine its relationships with other intrasellar abnormalities, pituitary function, and adverse perinatal events. One hundred and ninety-three patients had isolated GH deficiency, 43 had multiple pituitary hormone deficiency, 10 had diabetes insipidus, 17 had hypogonadotropic hypogonadism, 5 had idiopathic delayed puberty, 47 had precocious puberty, and 24 had other hypothalamic pituitary disorders of hyperfunction. One tenth (10.9%) of the patients (37 cases) had empty sella, with a marked variation of incidences among the disorders listed above. A statistically higher frequency of subjects with empty sellae was found only in patients with multiple pituitary hormone deficiency. Patients with and without empty sellae were not different in regard to age or sex. The incidence of empty sella in the various groups of patients was as follows: isolated GH deficiency, 8.8% (17 cases); multiple pituitary hormone deficiency, 34.9% (15 cases); hypogonadotropic hypogonadism, 5.9% (1 case); idiopathic delayed puberty, 40% (2 cases); and precocious puberty, 4.2% (2 cases). No patients with isolated diabetes insipidus or other hypothalamic-pituitary disorders had empty sellae. In the patients with empty sellae, abnormalities of the stalk or posterior lobe were found in 1 patient with isolated GH deficiency (5.9%), 13 patients with multiple pituitary hormone deficiency (86.7%), and no patients with puberty disorders. Likewise, adverse perinatal events were found only in 1 patient with isolated GH deficiency and 9 patients with multiple pituitary hormone deficiency. These findings suggest that empty sella is not rare in children and adolescents evaluated for hypothalamic-pituitary disorders, particularly if there is multiple pituitary hormone deficiency. Empty sella can be found regardless of abnormalities of the stalk and posterior lobe, and adverse perinatal events do not seem to be the primary etiological factor. Empty sella is usually associated with pituitary hypofunction, but it can be found in patients with hyperfunction of the hypothalamic-pituitary-gonadal axis.

Growth and thyroid function in children treated with growth hormone.

We examined the effect of growth hormone (GH) therapy on thyroid function in 57 children with isolated GH deficiency and whether this effect could influence their growth response. Thyroid function and insulin-like growth factor I levels were measured before and after 3, 6, and 12 months of recombinant-GH therapy (20 U/m2 per week, given subcutaneously), after a 1-month withdrawal from therapy, and after a further 6 months of GH administration. The serum concentration of triiodothyronine (T3) and the T3/T4 (thyroxine) ratio increased after 12 months of GH treatment, whereas total T4 and free T4 levels decreased; thyrotropin levels did not change significantly during treatment but increased after a 1-month withdrawal. After a further 6 months of GH therapy, an increase in T3 levels and in the T3/T4 ratio and a decrease in total T4 and free T4 levels were found again, and thyrotropin levels decreased. The increment in growth velocity after 12 months of therapy correlated positively with the T3/T4 ratio and negatively with total T4 and free T4 values. These data confirm in children a GH-induced enhancement of peripheral conversion of T4 to T3. This effect appears to be more evident in children who are most sensitive to GH in terms of growth-promoting activity.

Follow-up of antibodies to growth hormone in 210 growth hormone-deficient children treated with different commercial preparations.

The aim of the study was to evaluate the immunogenicity of different commercial recombinant-growth hormone preparations. The presence of antibodies to growth hormone was tested in 210 growth hormone-deficient children at 6-month intervals during treatment for 6-66 months. The patients were treated with three preparations (groups A, B and C of 70 cases each) having the authentic growth hormone sequence. Groups A and B received hormone synthesized by the recombinant DNA technique in E. coli, while the group C preparation was produced in a mammalian cell line. The preparations showed poor immunogenicity and antibodies were found as follows: 1.4% in patients of group A (1 case: binding capacity 0.2 mg/l and Ka 3.5 10(7) l M-1), 2.8% in patients of group B (2 cases; case 1 binding capacity 0.7 mg/l and Ka 1.5 10(7) l M-1; case 2 binding capacity 0.04 mg/l and Ka of 1.8 10(8) and 6.5 10(6) l M-1), and 8.5% in group C (6 cases; binding capacity from 0.4 to less than 0.02 mg/l, Ka from 1.6 10(7) to 3.8 10(8) l M-1). Only two patients of group C presented the antibodies in two subsequent examinations; in the other patients the positivity was found once. In all patients positive samples were found at intervals of 6-24 months after the start of therapy. In all antibody-positive patients growth velocity presented no decrease at the time of antibody detection and was never different to that of negative patients. We conclude that the three commercial preparations examined showed poor immunogenicity without clinical relevance.