Renal failure, also known as kidney failure, occurs when the kidneys can't perform their normal functions. It usually occurs in middle-aged and older people. The kidneys are two bean-shaped organs on either side of the spine in the lower back. Their main functions are to remove waste from the body and to balance the water and mineral content of the blood by filtering waste, minerals, and water. The waste and water combine to form urine.

Anatomy of the Kidney

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End-stage renal disease (ESRD) refers to a permanent condition in which the kidneys are no longer able to filter waste from the blood. As the wastes build up, the tiny filters in the kidneys continue to lose their filtering ability. Although damage to the nephrons may occur suddenly after an injury or poisoning, many kidney diseases take years or decades to cause noticeable damage. ESRD is generally diagnosed when kidney function drops to 10% of normal. The two most common causes of ESRD are:

    
  • Diabetes—the nephrons are damaged by chronically high blood sugar levels that occur in poorly controlled diabetes
  • High blood pressure—causes damage to the blood vessels in the kidneys
  • End-stage renal disease can lead to anemia, high blood pressure, bone disorders, heart failure, and mental confusion.