COMMENT
Acute kidney injury has three categories, they are prerenal, postrenal, and intrarenal/intrinsic. The first category, prerenal, means that the injury to the kidney occurs before the kidney itself. This type of injury is caused because of reduced perfusion of the kidney. This reduction can be caused by absolute decrease in circulating volume caused by hemorrhage, dehydration, or burns. It can also be caused by relative decrease in circulating volume caused by, distributive shock, third-spacing and edema, or decreased cardiac output. Another cause can be renal abnormalities such as occlusion or stenosis of the renal artery. The second category is postrenal, this can be caused by obstruction of normal outflow of urine from the kidneys. Things that can cause this are: benign prostatic hyperplasia, kinked or obstructed catheters, intraabdominal tumors, strictures, or calculi. The third category is intrarenal/intrinsic, this involves either vascular, interstitial, glomerular, or tubular. If it is vascular, it can be caused by vasculitis, emboli, or nephrosclerosis (due to primary hypertension, hypertensive emergencies, and urgency). If interstitial, it can be caused by acute allergic interstitial nephritis or acute pyelonephritis. If glomerular, it can be caused by acute glomerulonephritis. If tubular, it can be caused by ischemic issues such as prolonged prerenal failure, transfusion reactions, or rhabdomyolysis. Tubular can also be caused by nephrotoxic issues like prolonged post renal failure, certain antimicrobials (antibiotics, antifungals, and antiviral drugs), radiographic contrast media, certain cytotoxic chemotherapy agents, recreational drugs, environmental agents, and snake and insect venom.
