Idiopathic hypothalamic diabetes insipidus, pituitary stalk thickening, and the occult intracranial germinoma in children and adolescents.

We report nine consecutive children and adolescents [five females and four males; aged 2 yr 8 months (m) to 18 yr 1 m] studied over the last 5 yr with idiopathic central diabetes insipidus. In addition to vasopressin deficiency, anterior pituitary hormone deficiencies were detected, either on evaluation at presentation or during follow-up studies over the following 3 yr. Four patients had an increased concentration of plasma PRL. One patient had multiple pituitary hormone deficiencies at diagnosis, and two others developed the same by 21 m of follow-up. Brain magnestic resonance imaging scans, performed at presentation, were originally interpreted as normal in four of nine patients, except for absence of the bright posterior pituitary signal; after retrospective review, two of nine were considered normal. All of the brain magnetic resonance imaging (MRI) scans showed positive findings by 14 m of follow-up. The first abnormal finding in all patients was isolated pituitary stalk thickening. Evaluation of cerebrospinal fluid (CSF) for hCG was positive in three of eight evaluated patients; the three positive CSF values were found at presentation and 3 and 9 m after presentation. All eight patients assessed were negative for CSF alpha-fetoprotein and cytology, and no patient had serum tumor markers. Transsphenoidal biopsy of the lesion in seven of nine patients showed a germinoma in six patients and inflammatory cells in one. The six patients with documented germinoma comprise 31% of the intracranial germinomas diagnosed in this age group at the University of California-San Francisco during the last 5 yr. The patient with mononuclear inflammatory cells on biopsy along with one other patient have had spontaneous resolution of their stalk thickening. So-called "idiopathic" central diabetes insipidus warrants close follow-up to determine the etiology, especially if anterior pituitary hormone deficiencies are detected. Normal brain MRI scans or scans that show isolated pituitary stalk thickening merit follow-up with serial contrast enhanced brain MRI for the early detection of an evolving occult hypothalamic-stalk lesion. CSF evaluation is recommended at presentation because elevated CSF hCG may precede MRI abnormalities.

Glucagon-induced small bowel air reflux: degrading effects on double-contrast colon examination.

Glucagon-induced small bowel air reflux and its effect on the diagnostic quality of the double-contrast barium enema examination was prospectively evaluated in 103 patients. These were randomly assigned to receive 0.5 mg intravenous glucagon (50 patients) or to a control group without such medication (53 patients). The group receiving glucagon demonstrated an increased amount of small bowel air and a greater magnitude of change in its volume secondary to reflux, as well as degradation in the quality of barium enema study when compared to the nonglucagon group. No significant improvement in visualization of the appendix after glucagon was observed. We conclude that routine administration of glucagon during double-contrast enema would degrade the quality of examination primarily because it promotes retrograde reflux of air into the small intestine.

Endocrine, histological, and biochemical studies of adrenocorticotropin-producing islet cell carcinoma of the pancreas in childhood with characterization of proopiomelanocortin.

Two 8-yr-old children, a boy and girl, are described with Cushing's syndrome secondary to ectopic ACTH-secreting pancreatic islet cell carcinomas. The girl, seen 28 yr ago, had strong presumptive evidence of ectopic ACTH production and hypercalcemia. The boy, studied recently, had strikingly elevated concentrations of plasma ACTH (1,500 pg/ml) and beta-lipotropin (beta LPH; 2,500 pg/ml) and showed no suppression of urinary 17-hydroxycorticoids or cortisol with low and high dose dexamethasone. He had increased plasma calcitonin (257 pg/ml), glucagon (442 pg/ml), lactate dehydrogenase (497 IU/liter), and alpha-fetoprotein (5,144 pg/ml). He also had hypokalemic alkalosis with elevated plasma deoxycorticosterone (70 ng/ml) and PRA (6.9 ng/ml.h) but normal plasma aldosterone (8.2 ng/dl) and 18-hydroxycorticosterone (7.6 ng/dl). Preoperative localization of the tumor was accomplished by computed tomographic scan of the abdomen with concurrent barium enema. Cell-free translation of the tumor mRNA produced authentic proopiomelanocortin of 35,000 mol wt, indicating that the ACTH and beta LPH were produced by the tumor from a common precursor. After removal of a large amount of metastatic tissue from the boy, clinical progression of the remaining tumor was monitored by measuring plasma ACTH and beta LPH. Episodic secretion of ACTH and beta LPH was demonstrated by taking frequent plasma samples while suppressing pituitary ACTH with oral dexamethasone. Chemotherapy and radiation proved ineffective in controlling the growth of his tumor.