Kidney Diseases: How Kidneys Work and What Can Go Wrong

How kidneys work

You have two kidneys, each about the size of your fist, near the middle of your back just below the rib cage.

• Each holds about a million tiny filters called nephrons.
• They filter your blood, removing wastes and extra water as urine.
• Urine flows through tubes called ureters to the bladder, which stores it until you go to the bathroom.

Kidney disease

Most kidney diseases attack the nephrons, which can leave the kidneys unable to remove wastes.

• Causes include genetic problems, injuries and medicines.
• Higher risk: diabetes, high blood pressure, or a close relative with kidney disease.
• Chronic kidney disease damages the nephrons slowly, over several years.

Other kidney problems include cancer, cysts, stones and infections.

Testing and treatment

Blood and urine tests show whether you have kidney disease. If your kidneys fail, you will need dialysis or a kidney transplant.

Sources

Based on "Kidney Diseases," MedlinePlus, U.S. National Library of Medicine, drawing on the NIH National Institute of Diabetes and Digestive and Kidney Diseases; a work of the United States government in the public domain.