Diuresis in AKI

Q: Diuresis during resolution of acute kidney injury (AKI) is due to?

A) Glucosuria
B) Urea diuresis
C) Sodium diuresis
D) Water diuresis
E) Formation of new nephrons


Answer: B

Resolution of AKI causes diuresis due to urea as azotemia gets resolved. Urea is an osmotic agent. There are two other major causes of urea diuresis in ICU beside resolution of AKI. One is steroid therapy which causes tissue catabolism, and the second is the addition of high amounts of protein orally via a feeding tube or parenteral nutrition.

 Glucosuria also causes solute diuresis alike urea diuresis but it is in the setting of hyperglycemia (choice A).

 Sodium diuresis occurs during intravenous (IV) saline administration. A similar mechanism occurs when bilateral urinary tract obstruction is relieved. This should be distinguished from urea diuresis and is not exactly due to the resolution of AKI (choice C).

Water diuresis occurs during primary polydipsia, central Diabetes Insipidus, and nephrogenic Diabetic Insipidus (choice D).

Formation of new nephrons does not occur during resolution of AKI (choice E).

#nephrology


Reference: 

Forni LG, Darmon M, Ostermann M, et al. Renal recovery after acute kidney injury. Intensive Care Med. 2017;43(6):855–866. doi:10.1007/s00134-017-4809-x