What is Kidney (Renal) Failure?

Sometimes kidneys are no longer able to filter and clean blood. This can cause unsafe levels of waste products to build up. This is known as kidney (or renal) failure. Unless it is treated, this can cause death.

Female Urinary Tract
Female Urinary Tract
Medical Illustration Copyright © 2015 Nucleus Medical Media, All rights reserved

Male Urinary Tract
Male Urinary Tract
Medical Illustration Copyright © 2015 Nucleus Medical Media, All rights reserved

How the kidneys filter waste from your blood
How the kidneys filter waste from your blood
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health

What are Kidneys?

The kidneys are 2 bean-shaped organs, each about the size of a fist. They are found in your back on either side of the spine. Healthy kidneys clean waste products from the blood by making urine. They also balance the amount of certain elements in your blood (such as sodium, potassium, and calcium), and make hormones that control blood pressure and red blood cells.

What is Kidney Failure?

Kidney (renal) failure is when kidneys don't work as well as they should. The term "kidney failure" covers a lot of problems. These problems can result in kidney failure:

  • Your kidney doesn't get enough blood to filter
  • Your kidney is hurt by a disease like
    • high blood sugar (diabetes)
    • high blood pressure
    • glomerulonephritis (damage to the kidney's tiny filters)
    • polycystic kidney disease
  • Your kidney is blocked by a kidney stone or scar tissue


What are the Signs of Kidney Failure?

The symptoms can differ based on how bad the kidney failure is, how quickly it is getting worse, and what is causing it.

There are 2 main types of kidney (renal) failure:  acute (sudden) and chronic (over time).

Acute Renal Failure – ARF

ARF occurs when the kidneys suddenly stop filtering waste products from the blood.

The signs of ARF can be:

  • swelling of the hands, feet and face (edema)
  • internal bleeding
  • confusion
  • seizures
  • coma
  • abnormal blood and urine tests
  • high blood pressure

Chronic Renal Failure – CRF

CRF builds slowly with very few symptoms in its early stages.

A patient with CRF may not have any symptoms until kidney function declines to 20% or less. At that stage, these signs may appear:

  • abnormal blood and urine tests
  • high blood pressure
  • weight loss for no reason
  • low red blood cell count (anemia)
  • nausea
  • vomiting
  • metal taste in your mouth
  • loss of appetite
  • shortness of breath
  • chest pains
  • numbness and tingling
  • confusion
  • coma
  • seizures
  • easy bruising
  • itching
  • fatigue
  • headaches
  • muscle twitches and cramps
  • weak bones that break easily
  • yellow-brown skin color
  • itching
  • swelling of the hands, feet and face (edema)
  • trouble sleeping


What Causes Kidney Failure?

ARF is most likely to happen with:

  • low blood flow (such as after complicated surgery or an accident)
  • swelling of the kidney (such as a reaction to a drug or infection)
  • sudden blockage (such as by a kidney stone)
  • very high blood pressure

With ARF, the kidney often returns to normal or near normal after the cause is treated.

CRF is permanent loss of kidney function. The most common causes are:

  • high blood pressure
  • chronic glomerulonephritis (kidney damage)
  • high blood sugar (diabetes)
  • polycystic kidney disease
  • blocked urinary tract
  • kidney infection


How is Kidney Failure Diagnosed?

Kidney failure is most often found with a blood test called a "creatinine level." Creatinine is a molecule made by your muscles. A normal kidney will remove extra creatinine from the blood stream and get rid of it in urine. More creatinine in the blood is a sign that the kidneys aren't cleaning the blood as well as they should. This test can spot something is wrong before a patient with kidney failure feels sick.



How is Kidney Failure Treated?

To treat ARF, you have to treat the cause (such as blood pressure that is too high or too low, a kidney stone or high blood sugar). Sometimes you need dialysis for a short time.

With CRF, treating the cause (such as high blood pressure and/or high blood sugar) can slow the disease. CRF can lead to end stage kidney disease.

When kidney function falls below 10% of normal, dialysis or a kidney transplant is most often needed, especially if you have signs of uremia (a buildup of waste in the blood), like nausea and itching.

Hemodialysis Treatment
Hemodialysis Treatment
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health

Peritoneal Dialysis of the Abdominal Cavity
Peritoneal Dialysis of the Abdominal Cavity

Dialysis

Dialysis is a way to pump your blood through a machine that filters out the waste and returns the blood to your body. The 2 types of dialysis are hemodialysis and peritoneal dialysis.

Hemodialysis:  For hemodialysis, a tube (catheter) is stuck into one of the veins in your neck, or an arm or leg. Hemodialysis is most often done 3 times a week for 3 to 4 hours at a time.

Peritoneal dialysis: Peritoneal dialysis is done through a tube permanently set in your belly.

Most adults have dialysis done in an outpatient hemodialysis center. Most children have peritoneal dialysis done at home.

Kidney Transplant

A kidney transplant is when a surgeon puts a healthier kidney from another person into your body. Kidney transplant is the best way to treat many patients with end stage kidney failure.

Kidneys for transplant come from people who have agreed to donate their kidneys when they die (deceased donors) or donated by healthy people (living donors). Living donors are most often family members of the patient. There is a shorter wait time to surgery for a transplant from a living donor. (This is because there is a waiting list for kidneys from deceased donors and not enough donors.) Also, patients with kidneys donated by living donors live longer (and the kidneys last longer) than those with kidneys from deceased donors or who just stay on dialysis.

With modern medical techniques, the living kidney donor doesn't need to be a blood family member to get a good result.

About 90,000 patients are on the wait list for deceased donor kidney transplants in the U.S. But only 10,000 deceased donor kidney transplants are done each year due to the lack of donated kidneys. Another 6,000 kidney transplants are done each year from living kidney donors.