renal

Pre-renal AKI vs ATN

Renal Failure

Pre-renal AKI vs ATN
Feature	Pre-renal AKI	Acute Tubular Necrosis (ATN)
Mechanism
FeNa	<1% (kidneys conserving Na⁺)	>2% (damaged tubules cannot conserve Na⁺)
FeUrea	<35%	>50%
Urinalysis	Bland/concentrated	Muddy brown granular casts
Response to Fluids	Improves rapidly with volume	Does NOT improve promptly with fluids

Comparing: Pre-renal AKI

<1% (kidneys conserving Na⁺)

<35%

Bland/concentrated

Improves rapidly with volume

For healthcare-professional education. Clinical decisions require patient-specific assessment and local protocols.