OBJECTIVE Appropriate replacement doses of glucocorticoid are important to determine in primary and secondary adrenal deficiency in children, both to avoid the risks of hypoglycaemia and adrenal crisis associated with undertreatment, and to avoid growth suppression and reduced final height potential associated with steroid excess. The aim of this study was to assess how closely conventional twice daily hydrocortisone administration mimics physiological cortisol secretion in a group of ACTH-deficient children and adolescents.PATIENTS Fifty children and adolescents (aged 3-20 years) were studied who had had surgery +/- radiotherapy to the hypothalamopituitary region for removal of a craniopharyngioma. The patients were subdivided into two groups: group I comprised 44 patients known to be ACTH deficient (as determined by glucagon or insulin provocation tests of anterior pituitary function performed after surgery) and maintained on twice daily oral hydrocortisone replacement; group II comprised six patients known to be ACTH sufficient at their last assessment of pituitary function and not on hydrocortisone replacement. A third group of 10 boys (aged 7-13 years) who had no known endocrinopathy were used as controls (group III).MEASUREMENTS After intravenous cannula insertion, blood samples were taken every 2 h for measurement of plasma cortisol and glucose over a period of 24 h. Patients in group I continued on their usual doses of hydrocortisone, prescribed at 0800 and 1800 h. RESULTS The mean total daily replacement dose of hydrocortisone for patients in group I was 12.3 mg/m(2)/day (range, 5.5-18.5). On the conventional twice daily dose regimen, there was a supraphysiological medium plasma cortisol level (629 nmol/l, range 185-1600; z = -3.76, P = 0.0002) 2 h after the morning dose relative to the control group, and a prolonged and unphysiological nadir from 1400-1800 h (median at 1600 h 42 nmol/l, range 13-1170; z = -3.13, P < 0.002) before the second dose of hydrocortisone was administered. Cortisol values were low, and often negligible, during the early hours of the morning (median at 0600 h 15 nmol/l, range 13-277, z = -4.87, P < 0.00001) and spontaneous hypoglycaemia was documented in one patient on a single 0800 h sample. One patient in group II was shown to be unequivocally cortisol deficient and median cortisol values for the remaining five suggested a suboptimal rise in plasma cortisol during the early hours of the morning.CONCLUSION Our cohort of patients provides an excellent model for the study of glucocorticoid replacement in cortisol-deficient children and adolescents and shows, as in adults, that the aim of mimicking the physiological nyctohemeral secretion of cortisol is difficult to achieve in practice and raises a number of important considerations unique to steroid substitution therapy in this age group.

Objective: To quantify the extent of hypothalamic damage after surgery for craniopharyngioma using magnetic resonance imaging (MRI) and to relate the findings to changes in body mass index (BMI).Patients: Sixty-three survivors (36 males, 27 females) of childhood craniopharyngioma were treated surgically between 1973 and early 1994.Methods: Cranial MRI was performed at a structured follow-up assessment 1.5-19.2 yr after the initial surgery. Hypothalamic damage was scored as 0 (no visible damage), 1 (intermediate), or 2 (severe).Results: After surgery there was an increase in BMI standard deviation (SD) from diagnosis to study assessment in all but 7 patients. However, patients with MRI scores of 2 (n = 17) had a significantly greater increase in median BMI so score at follow-up (+5.5 SD score), compared with +2.5 so score and +1.1 so score for patients with MRI scores of 1 or 0, respectively. Of the 17 cases with MRI scores of 2, 10 had a history of extreme weight loss or weight gain at presentation; preoperative neuroimaging demonstrated extensive hypothalamic infiltration by tumor in these cases.Conclusion: MRI gives sufficient anatomical definition to allow assessment of the extent of hypothalamic damage and, thereby, prediction of the patients most at risk for severe post-operative weight gain.

Seventy-five children treated for craniopharyngioma between 1973 and 1994 were studied to demonstrate which pre- and intraoperative factors were indicative of a poor outcome as defined by a quantitative assessment of morbidity. This involved a retrospective review of 65 patients and a prospective study of 10 patients focused on clinical details and cranial imaging and a follow-up "study assessment" of 66 survivors performed over the last 2 years. As part of the assessment, 63 patients underwent magnetic resonance imaging with a three-dimensional volume acquisition sequence 1.5 to 19.2 years after initial surgery. Predictors of high morbidity included severe hydrocephalus, intraoperative adverse events, and young age ( < or = 5 years) at presentation. Predictors of increased hypothalamic morbidity included symptoms of hypothalamic disturbance already established at diagnosis, greater height ( > or = 3.5 cm) of the tumor in the midline, and attempts to remove adherent tumor from the region of the hypothalamus at operation. Large tumor size, young age, and severe hydrocephalus were predictors of tumor recurrence, whereas complete tumor resection (as determined by postoperative neuroimaging) and radiotherapy given electively after subtotal excision were less likely to be associated with recurrent disease. Based on these findings, the authors propose an individualized, more flexible treatment approach whereby surgical strategies may be modified to provide long-term tumor control with the lowest morbidity.

The growth and endocrine sequelae of 75 children (33 girls and 42 boys) with craniopharyngioma, treated from 1973 to 1994, were studied by retrospective review and by follow up assessment in 66 survivors, with a mean time from initial surgery of 6.7 years (range 1.5 to 19.8 years). Although infrequently complained of, 71% of patients had symptoms to suggest an endocrinopathy at diagnosis. After surgery, multiple endocrinopathies were almost universal, such that 75% of children had panhypopituitarism at follow up. Hypoadrenal crises in association with intercurrent illness contributed significantly to morbidity and mortality, as did the metabolic consequences of concomitant antidiuretic hormone (ADH) insufficiency and absent thirst. Final height in 25 patients was significantly below genetic target height, particularly in the girls, with loss of height potential occurring during the pubertal years. The endocrine morbidity associated with craniopharyngioma and its treatment remains high but manageable with appropriate hormone replacement. However, the combination of ADH insufficiency and an impaired sense of thirst following aggressive surgery and severe hypothalamic injury remains one of the most complex management problems.

Childhood onset anorexia nervosa may be difficult to diagnose because of the lack of clear diagnostic criteria for prepubertal children and because of the difficulty of differentiating psychogenic from organic disease.' Psychological disturbance and symptoms of anorexia without neurological manifestation may also be presenting features of an early intracranial lesion, usually affecting the diencephalon-as shown by the following three cases.Case reports CASE 1

Children with growth failure, whether secondary to an endocrinopathy such as growth hormone deficiency or secondary to neurological handicap with poor nutrient intake, grow at a subnormal rate but it is most unusual for a child to have complete growth arrest.

When unlimited supplies of biosynthetic human growth hormone (hGH) became available in the late 1980s, the envisaged potential of its therapeutic applications was enormous in that it was hoped that perhaps most short children would be able to be made taller. However, this seems to have been far too simplistic a view and certainly in those children with various growth disorders treated with pharmacological doses of growth hormone (GH), the potential for increased final height does not appear to be fulfilled, with the exception of girls with Turner's syndrome. Further challenges in the growth field involve the manipulation of pubertal development during concomitant GH therapy.