Abstract.
A 710 g male infant was born at a referring hospital at a gestational age of 23 weeks and 2 days via vaginal delivery and was transferred to our facility at 14 days of age. His delivery was complicated by the breech presentation with difficult head extraction. The infant’s initial course was significant for respiratory distress syndrome, grade III-IV intraventricular hemorrhage (IVH), acute kidney injury, and large PDA. On the day of life 29, a gradual increase in serum sodium level refractory to increasing total fluid volume was noted. The combination of persistent hypernatremia (150–160 mmol/l), polyuria (8.4 ml/kg/hr), high plasma osmolality (323 mosm/kg), hyposthenuria (75 mosm/kg) and an undetectable serum ADH (<0.8 pg/ml) confirmed the diagnosis of central diabetes insipidus (CDI). Serum sodium and urine output decreased and urine osmolality increased after subcutaneous DDAVP administration. CDI is an uncommon cause of hypernatremia in the neonatal period. The diagnosis can be difficult as excessive urine output and high serum sodium can often be attributed to high insensible water loss in the extremely premature newborn. CDI in our patient was thought to be due to grade III-IV IVH complicated by post-hemorrhagic hydrocephalus. In conclusion, the diagnosis of central DI should be considered as a complication of severe IVH in the extremely premature neonate who demonstrates persistent hypernatremia, polyuria, decreased urine osmolality, and increased plasma osmolality. Serum ADH levels can be helpful in confirming the central origin of DI and subcutaneous desmopressin can be an effective treatment in the preterm infant.