What happens when the kidneys fail?

It depends: Acute kidney failure can happen for several reasons (blood loss, obstruction, toxin damage, immune response to name a few). The kidneys lose the ability to produce urine and eliminate waste, and you can get electrolyte imbalances, uremia, and acid base imbalances. If the damage happens over a longer period of time, you can get hypertension, heart failure, bone fractures, and anemia.

Uremia develops.: The body is unable to remove many of the toxins that originate from food and internal metabolism ;this leads to multiple malfunctions including hypertension, fluid retention, anemia, and eventually death from uremia.

Uremia: When the kidneys fail, usually a slow process, the blood collects toxins including urea - mostly end products of metabolism and you will get extremely sick. It is commonly associated with changes in blood pressure and requires serious attention by a renal specialist. Sometimes a kidney transplantation might be needed.