Physiopathology and diagnosis of nephrogenic diabetes insipidus.

Nephrogenic diabetes insipidus (NDI) is caused by an improper response of the kidney to the antidiuretic hormone arginine vasopressin (AVP), leading to a decreased ability to concentrate urine which results in polyuria and polydipsia. The clinical diagnosis of NDI relies on demonstration of subnormal ability to concentrate urine despite the presence of AVP. NDI is most commonly acquired, secondary to kidney disorders, electrolyte imbalance and various drugs. Congenital forms of NDI are rare, and most commonly inherited in a X-linked manner with mutations of the AVP receptor type 2 (AVPR2). Mutations of the water channel aquaporin-2 (AQP2) can be detected in autosomal recessive or dominant forms of NDI. Management of NDI should focus on free access to drinking water and reduction of polyuria.