pituitrin and Germinoma

Diabetes insipidus is a heterogeneous condition characterised by polyuria and polydipsia caused by a lack of secretion of vasopressin, its physiological suppression following excessive water intake, or kidney resistance to its action. The clinical and laboratory diagnosis is confirmed by standard tests, but recent advances in molecular biology and imaging techniques have shed new light on the pathophysiology of this disease. In many patients, central diabetes insipidus is caused by a germinoma or craniopharyngioma; Langerhans' cell histiocytosis and sarcoidosis of the central nervous system; local inflammatory, autoimmune or vascular diseases; trauma from surgery or accident; and, rarely, genetic defects in vasopressin biosynthesis inherited as autosomal dominant or X-linked recessive traits. Thirty to fifty percent of cases are considered idiopathic. Tumour-associated central diabetes insipidus is uncommon in children younger than 5 years old. Biopsy of enlarged pituitary stalk should be reserved for patients with hypothalamic-pituitary mass and progressive thickening of the pituitary stalk since spontaneous recovery may occur. Molecular biology in selected patients may identify those with apparently idiopathic diabetes insipidus carrying the vasopressin-neurophysin II gene mutation.

Topics: Autoimmune Diseases; Brain Neoplasms; Child; Diabetes Insipidus, Neurogenic; Germinoma; Humans; Neurophysins; Vasopressins

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.

Topics: Adolescent; alpha-Fetoproteins; Biopsy; Brain Neoplasms; Child; Child, Preschool; Chorionic Gonadotropin; Diabetes Insipidus; Female; Germinoma; Humans; Hypothalamus; Magnetic Resonance Imaging; Male; Pituitary Gland; Pituitary Hormones, Anterior; Vasopressins

Patients who have suprasellar germinomas in childhood often present with central diabetes insipidus (CDI). The authors investigated the use of aqueous vasopressin (AVP) by continuous infusion to control the fluid and electrolyte balance in germinoma patients with CDI during aggressive fluid hydration as a part of a preirradiation chemotherapy protocol.. Three patients with suprasellar germinomas and CDI were treated with four courses of preirradiation chemotherapy. Two patients were treated with a continuous AVP infusion at an initial rate of 0.08-0.10 mU/kg per hour during hydration. Fluid intake, urine output, body weight, urine specific gravity, and serum electrolyte concentrations were monitored closely, and the infusion rate was adjusted accordingly.. Very low dose AVP infusion controlled fluid balance while allowing appropriate diuresis during chemotherapy. Fluid intake and output were markedly less in the AVP-treated patients (3.8 L/m2 per day) than in the untreated patient (20 L/m2 per day).. The use of very low dose AVP infusion at an initial rate of 0.08-0.10 mU/kg per hour during hydration therapy allowed easily titratable control of fluid and electrolyte balance in the patients studied and avoided the complications associated with desmopressin acetate antidiuresis or withholding antidiuretic treatment altogether.

Topics: Adolescent; Brain Neoplasms; Child; Combined Modality Therapy; Diabetes Insipidus; Female; Germinoma; Humans; Infusions, Intravenous; Male; Vasopressins