Diagnostic Pitfalls of a Newborn with Congenital Nephrogenic Diabetes Insipidus
Ömer Güran1, Serçin Güven, Heves Kırmızıbekmez, Özlem Akgün Doğan, Leyla Karadeniz Bilgin1University of Health Sciences, Umraniye Training and Research Hospital, Department of Neonatology, Istanbul, Turkey 2University of Health Sciences, Umraniye Training and Research Hospital, Department of Paediatric Nephrology, Istanbul, Turkey 3University of Health Sciences, Umraniye Training and Research Hospital, Department of Paediatric Endocrinology and Diabetes, Istanbul, Turkey 4University of Health Sciences, Umraniye Training and Research Hospital, Department of Paediatric Genetic, Istanbul, Turkey
Congenital nephrogenic diabetes insipidus (NDI) is a rare cause of hypernatremia in newborns. Central diabetes insipidus (CDI) is the main differential diagnosis of NDI. NDI responds poorly to desmopressin acetate (DDAVP) treatment while this is the mainstay of CDI management. Therefore, an early and correct diagnosis of NDI is crucial to avoid the complications of inappropriate therapy. Here, we report a newborn with hypernatremia and hypotonic polyuria. The patient was initially responsive but subsequently unresponsive to intranasal DDAVP treatment in regard to urine output and serum sodium levels. A novel hemizygous missense mutation (c.632T>C, p.L211P) in the AVPR2 gene was found both in the baby and his mother, and the diagnosis of congenital NDI was established. After hydrochlorothiazide treatment and hypo-osmolar formula were given, urine volume was decreased, and serum sodium levels were normalized. Early recognition and appropriate management of NDI can prevent complications of hypernatremic dehydration in young infants.