hypertonic saline test - somber

[ArchivalUser]

does anyone know how hypertonic saline test is able to distinguish between central and nephrogenic diabetes insipidus?

[ArchivalUser]

3% saline is infused to achieve plasma Na of 145-150 mmol/l, and AVP and Posm are measured. Patients with primary polydipsia and nephrogenic DI exhibit normal stimulation of AVP release in response to hypertonicity; whereas those with central DI exhibit little or no rise in AVP.

[ArchivalUser]

Thanks so much