What is kidney failure?

Kidney failure (also called renal failure) means one or both kidneys can no longer function well on their own. Sometimes, kidney failure is temporary and comes on quickly. Other times, it is a chronic condition that can get worse slowly over a long time.

Kidney failure may sound serious, and it is. But treatments such as dialysis and kidney transplant help many people with limited kidney function continue to live fulfilling lives.

What do the kidneys do?

The kidneys have several jobs. One of the most important is helping your body eliminate toxins. The kidneys filter your blood and send waste out of your body in urine.

The kidneys are bean-shaped organs about the size of your fist. They sit under your ribcage, toward your back. Most people have two working kidneys, but people can live well as long as at least one is working correctly.

When the kidneys don’t work effectively, waste products build up in your body. If this happens, you might feel sick. In the most serious situations, kidney failure can be life-threatening. However, many people can manage kidney failure with the right treatment.

What causes kidney failure?

The most common causes of kidney failure are diabetes and high blood pressure. Sometimes, though, kidney failure happens quickly due to an unforeseen cause.

When the kidneys lose function suddenly (within hours or days), it’s called acute kidney failure (or acute kidney injury). This type of kidney failure is often temporary. Common causes of acute kidney failure can include:

  • Autoimmune kidney diseases
  • Certain medications
  • Severe dehydration
  • A urinary tract obstruction
  • Uncontrolled systemic disease like heart or liver disease

Kidney failure usually doesn’t happen overnight. Chronic kidney disease refers to a group of health conditions that affect how well your kidneys function over time. If left untreated, chronic kidney disease can lead to kidney failure.

The biggest causes of kidney failure from chronic kidney disease are:

  • Diabetes: Unmanaged diabetes can lead to uncontrolled blood sugar levels. Consistently high blood sugar can damage the body’s organs, including the kidneys.
  • High blood pressure: High blood pressure (hypertension) means blood travels through your body’s blood vessels with increased force. Over time, untreated high blood pressure levels can damage the kidneys’ tissue.

Other causes of chronic kidney disease include:

  • Polycystic kidney disease, a hereditary condition where cysts (fluid-filled sacs) grow inside your kidneys.
  • Glomerular diseases, such as glomerulonephritis, which affect how well the kidneys can filter waste.
  • Lupus and other autoimmune diseases that can affect multiple body systems.

What are the symptoms of kidney failure?

In early stages of kidney disease, many people experience few or no symptoms. It’s important to note that chronic kidney disease can still cause damage even though you feel fine.

Chronic kidney disease and kidney failure can cause different symptoms for different people. If your kidneys aren’t working properly, you may notice one or more of the following signs:

  • Fatigue (extreme tiredness)
  • An upset stomach or vomiting
  • Confusion or trouble concentrating
  • Swelling, especially around your hands or ankles
  • More frequent bathroom trips
  • Muscle spasms (muscle cramps)
  • Dry or itchy skin
  • Poor appetite or metallic taste of food

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