Natural History of ATN vs Prerenal

• Prerenal AKI will improve with fluids within hours

• ATN: Initiation Phase (hours to days)

• Period of ischemia or exposure to toxins:

• Reduced GFR from reduced blood flow

• Tubular Obstruction and Backleak

• Maintainance Phase (1-2 weeks)

• Parenchymal injury established

• GFR stable at < 10 cc/min

• Recovery

• Repair and regeneration lead to improvement in renal function