What are the causes of renal failure, and how are they categorized?

Prerenal
Hypoperfusion
Hypotension
Dehydration
CHF

Renal
Nephrotoxicity (e.g., chemotherapeutic agents, antibiotics, iodinated contrast)
Infection (e.g., glomerulonephritis)
Renal artery occlusion
Renal neoplasm or cysts

Postrenal
Obstruction of the ureter or bladder