Postrenal causes for renal failure result from obstruction of the collecting system of the kidney
, ureter, and bladder. The high back pressure generated can result in poor kidney
function and ultimately lead to kidney failure. Causes include from BPH (benign prostatic hypertrophy), ureteral obstruction by metestatic lymph nodes in some cases of cancer, stricture disease, obstruction secondary to stones, etc. These are problems that are usually urologic (taken care of by a urologist).