Syndrome of inappropriate antidiuretic hormone secretion in newborn infants with respiratory problems.

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has not often been described in newborn infants. Of 61 infants with respiratory problems who were admitted to our neonatal intensive care unit over a six-month period from July 1978, three had SIADH, diagnosed on the basis of hyponatremia, weight gain and the excretion of highly concentrated urine. In one infant the onset of marked hyponatremia was very rapid and resulted in deep coma. The occurrence of this syndrome in 5% of infants under intensive care for neonatal respiratory problems makes it essential to monitor these infants closely for deviations in fluid and electrolyte balance.