in which types of AKI, urine osmolality is high
what about urine Na+,FEna,serum BUN/Cr

prerenal azotemia(more than 500 mOsm/kg)

☆Na+ is reabsorbed in an attempt to conserve volume(e.g. ↑renin angiotensin system)→ less water in urin→ ↑osmolality, ↓urine Na(<20mEq/L) , ↓FEna(=excreted Na/filtered Na)(<1%), ↑serum BUN/Cr(urea is reabsorbed, creatinin not)(>20)

renal