pituitrin and Spasms--Infantile

We describe two sisters with chronic hypernatremia, lack of thirst, and inappropriate osmoregulated vasopressin secretion. Only one sister, who presented with microcephaly and developmental delay, showed signs of dysplasia of the midline structures (ie, septum pellucidum and corpus callosum) and a large intracranial cyst. Neither sister showed any signs of thirst, even when osmolality exceeded 337 mmol/kg. In both patients, the vasopressin secretion did not respond to either osmotic or nonosmotic stimuli or was suppressed by a water load. Plasma osmolality values returned to normal after treatment with forced hydration and a vasopressin analogue, desamino-D-arginine vasopressin. These findings indicate a severe defect in the hypothalamic osmoreceptors that control thirst and vasopressin secretion. To our knowledge, this is the first report of such a disorder in two sisters.

Topics: Aldosterone; Blood Urea Nitrogen; Female; Humans; Hypernatremia; Hypothalamus; Inappropriate ADH Syndrome; Infant; Osmolar Concentration; Renin; Sodium; Spasms, Infantile; Thirst; Vasopressins

The hypothalamic-pituitary-adrenocortical axis was studied in 10 infants before and during a six week period of treatment with adrenocorticotrophic hormone (ACTH) and three days and one and two weeks after its stopping. During the treatment 24 hour urinary cortisol excretion increased 20 to 350-fold (mean 100) above the basal value. Mean morning serum cortisol concentration, measured 24 hours after the preceding ACTH dose, did not increase. After the treatment mean urinary cortisol excretion was subnormal and mean morning serum cortisol concentration was below the pretreatment value. The mean serum cortisol response to a vasopressin test was reduced and shortened throughout the post-treatment observation period. The mean serum cortisol response to an intravenous ACTH test was not significantly different from the pretreatment response three days after treatment but was clearly reduced thereafter. At one and two weeks after treatment the basal concentrations of serum cortisol of one third of the patients and the post-ACTH concentrations of two thirds were subnormal. We conclude that in infants treatment with ACTH may cause adrenocortical hyporesponsiveness.

Topics: Adrenocorticotropic Hormone; Drug Therapy, Combination; Humans; Hydrocortisone; Hypothalamo-Hypophyseal System; Infant; Pituitary-Adrenal System; Spasms, Infantile; Vasopressins