Pre-renal - factors occurring before the kidney (hypotension- renal artery stenosis) Kidneys aren't getting blood supply, not being perfused, shock leads to renal failure because the kidneys are fine but there's not enough blood supply. Intra-renal - occurring within the kidney. Post- renal - factors occurring - after the kidney- (blockage of ureters, bladder etc) Kidneys are fine, after it's not.