What happens when your kidneys fail?
Healthy kidneys clean the blood by filtering out extra water and wastes. They also make hormones that keep your bones strong and blood healthy. When both of your kidneys fail, your body holds fluid. Your blood pressure rises. Harmful wastes build up in your body. Your body doesn't make enough red blood cells. You develop fatigue, nausea, and loss of appetite.
When this happens, treatment is needed to replace the work of your failed kidneys.
For more information, please see MedicineNet.com's Kidney Failure article.