RESUMEN
Congenital nephrogenic diabetes insipidus (NDI) is a rare disorder of the kidney characterized by the in ability to concentrate urine despite normal or elevated plasma concentration of the antidiuretic hormone agent vasopressin (AVP). We describe a case of congenital nephrogenic diabetes insipidus presenting with mild fever . The 3-day-old baby boy was admitted with mild fever. He has 6 members with DI in his family and his laboratoty finding showed hypernatremia, increased serum osmolarity and low level of urine specific gravity. Throughout the water deprivation test and the vasopressin test, he has been diagnosed as congenital NDI. Urinary free water loss was improved after treatment with hydrochlorothiazide and low salt formula. At the age 4 months, the infant has demonstrated normal growth and neurodevelopmental milestones. An early diagnosis of congenital NDI is very important, since the proper adequate management can prevent hyperosmolarity which might induce the delayed mental and physical development.