<prompt> Dispropoionately increased blood urea levels compared to serum creatinine urea creatinine ratio 20:1 can be seen in the following except -Prerenal failureCCFIntrinsic renal failureHypovolemia  <response>: Intrinsic or intrarenal acute renal failure ARF occurs when direct damage to the kidneys causes a sudden loss in kidney function. The most common causes of intrinsic acute renal failure are acute tubular necrosis ATN, acute glomerulonephritis AGN, and acute interstitial nephritis AIN . Ref Harrison20th edition pg 236 