Postrenal failure is characterized by what primary issue?

Postrenal failure is primarily characterized by a partial or complete obstruction of the urinary tract. This type of renal failure occurs when there is an obstruction that prevents urine from being excreted, which can lead to back pressure on the kidneys and subsequently impair their function. Conditions that may lead to postrenal failure include kidney stones, tumors, or an enlarged prostate, all of which can obstruct urine flow.

Understanding that the obstruction is key to this type of failure helps in managing the condition effectively, often by relieving the blockage, which can restore urine flow and kidney function. In contrast, other factors presented, such as uncontrolled hypertension or acute glomerulonephritis, relate to different types of renal failure and the underlying mechanisms affecting kidney function in distinct manners.