Three categories of injury:
Renal hypoperfusion (prerenal)
Most common cause of acute renal failure and is caused by renal hypoperfusion that occurs rapidly over a period of hours with elevation of BUN and plasma creatinine levels
Possible causes: hypovolemia, hemorrhagic blood loss, loss of plasma protein, water and electrolyte losses, hypotension or hypoperfusion, septic shock, cardiac failure or shock, massive pulmonary embolism stenosis or clamping of renal artery