Background: Severe neonatal autosomal-dominant polycystic kidney disease (ADPKD) is rare and easily confused with recessive PKD. Managing such infants is difficult and often unsuccessful.
Case diagnosis/treatment: A female infant with massive renal enlargement, respiratory compromise and hyponatraemia was treated with the arginine vasopressin receptor 2 antagonist tolvaptan. This resolved hyponatraemia, and there was no further increase in renal size.
Conclusion: Tolvaptan may be a useful treatment for severe neonatal PKD.
Keywords: Autosomal dominant polycystic kidney disease; Infant; Tolvaptan.