Diabetes insipidus (nephrogenic)

Nephrogenic diabetes insipidus is the result of renal resistance to the action of antidiuretic hormone, often described as blunting of the renal response, or failure of kidneys to concentrate urine (1). The result is polyuria. It most often has an osmotic basis but may arise in prolonged polyuria of any cause as a result of loss of the osmotic gradient across the collecting duct from washout of medullary solute.

Plasma ADH is high but appropriate for plasma osmolality; urine osmolality is inappropriately low. Secondary polydipsia maintains normonatraemia.

References:

1. Bockenhauer D, Bichet DG. Pathophysiology, diagnosis and management of nephrogenic diabetes insipidus. Nat Rev Nephrol. 2015 Oct;11(10):576-88. doi: 10.1038/nrneph.2015.89.