What Is Kidney Failure?

A patient with kidney failure undergoes dialysis treatment. Photo Courtesy: Helen H. Richardson/Denver Post/Getty Images

Kidney disease affects an estimated 37 million people living in the United States, and, according to the National Kidney Foundation, it is “the under-represented public health crisis” — in part because around 90% of people who have chronic kidney disease aren’t aware that they have it or that it can lead to complete kidney failure. This lack of awareness about kidney disease highlights exactly why it’s so important to learn more about what it is, how to recognize it and the role it plays in kidney failure.

Your Kidneys: What They Do and How They Work

Like all your organs, your kidneys play an integral role in the overall healthy functioning of your body. These are two bean-shaped organs that sit just below your ribcage, with one on either side of your spine. Each kidney is about the size of your fist, but despite their relatively small size, they have a big job to do.

These organs are responsible for filtering your blood by removing excess water and waste products like old red blood cells and acids that other cells create. In order for your muscles, nerves and other tissues to function properly, your body needs to have a healthy balance of water and minerals like potassium, calcium and sodium. Your kidneys help maintain this balance as they filter out excess material your body doesn’t need (and that may disrupt that balance).

One lesser-known role your kidneys play is that they also produce and excrete several hormones. These stimulate your body to create new red blood cells in your bone marrow when your oxygen levels are lower, and they also help your body effectively absorb calcium and phosphate — substances that your nerves and muscles need in order to work properly together.

Each one of your kidneys has about a million nephrons, which are the tiny filtration units that process and clean your blood, and each nephron has two important structures called a glomerulus and a tubule. When your heart pumps blood into your renal arteries, which are the large blood vessels that lead to your kidneys, it travels through progressively smaller blood vessels until it reaches the nephrons’ glomeruli. The glomeruli catch and remove the waste products from your blood before passing it into the tubules, which circulate the filtered blood back into your body. Excess water and the filtered blood waste products move into structures called ureters, and you then excrete them as urine. All in all, your kidneys process and filter about 30 gallons of blood each day.

Kidney Disease and Failure: What Happens and Why

Your kidneys are undeniably important when it comes to keeping almost every part of you healthy, but damage and disease can prevent them from working properly. When your kidneys are diseased and you don’t receive effective treatment, they can ultimately fail, which means they stop working completely.

Generally, “kidney disease” refers to any type of damage that happens to these organs that keeps them from filtering blood the way they should. Some other health conditions, particularly type 2 diabetes and high blood pressure, often cause and worsen kidney disease because they lead to damage in your kidneys’ blood vessels, which prevents them from efficiently circulating and filtering your blood. Having frequent urinary tract or kidney infections can also lead to damage. Even injury in a one-time event can lead to damage that prevents or or both of your kidneys from working the way they should.

Kidney damage typically requires treatment to prevent it from progressing into kidney failure, which it often leads to as it worsens. However, there are two main types of kidney failure to be aware of. The first is called acute kidney failure, which happens when one or both kidneys suddenly become unable to remove the waste products from your blood. This is more common with some sort of injury to your kidney that damages it beyond repair, but acute failure can also be a result of blood clots forming in kidney veins, infections, inflammation in the glomeruli or side effects from certain medications, such as chemotherapy drugs. If urine flow becomes blocked and your kidneys can’t excrete it — which typically occurs due to certain cancers or kidney stones — acute kidney damage that may lead to failure may take place.

Chronic kidney failure is the second type, and, like its name suggests, it refers to a long-term, gradual loss of kidney function that happens over time. Instead of a sudden health event taking place to stop your kidneys from working, as in the case of acute failure, chronic kidney failure progresses more slowly over time and is often the result of living with an untreated kidney-damaging disease. When you have chronic kidney failure, it can take months or years for these organs to reach the point that they fully fail.

In both cases, as your kidneys lose function, waste products can build up in your blood and cause a number of other uncomfortable health effects. Eventually, this can lead to complications like fluid building up in your lungs, loss of muscle function and chest pain. Without treatment that replaces the kidneys’ function and begins cleaning your blood again, kidney failure can be fatal. That’s one essential reason why it’s important to be familiar with kidney failure symptoms.

Symptoms of Kidney Failure

Just as acute and chronic types of kidney failure have different causes, they also have different symptoms to be aware of. Acute kidney failure may cause no symptoms at all, but some of the more common include a marked decrease in urine output, swelling in your legs and ankles, fatigue, confusion, weakness and nausea. If you notice any of these symptoms and they don’t resolve within a day or so, contact your doctor immediately. They may recommend that you seek emergency care, which you should also get if your physician is unavailable.

Chronic kidney failure often goes unnoticed in its earliest stages. That’s because it may not present any symptoms, and the symptoms of this condition tend to progress in severity at a rate that’s similar to the kidney failure itself. With chronic kidney failure, you may find yourself frequently losing your appetite or feeling nauseous. You may experience sleep disturbances, and your mental clarity and ability to recall information may feel diminished. Persistent itching is another symptom you might experience, and this happens when large amounts of waste products have built up in your blood. Chronic kidney failure also causes many of the same symptoms people with acute kidney failure experience.

Treatment for Kidney Failure

Getting kidney failure treatment is essential for survival. If you have acute kidney failure, you’ll likely be hospitalized to receive treatment. Your doctors will treat the underlying illness or health event that caused kidney damage while trying to balance the fluid levels in your body. They may give you medicine to balance mineral levels in your body and will likely put you on dialysis, which is a form of treatment that uses various processes or external machines to perform your kidneys’ function and remove the buildup of toxins in your blood.


If you have chronic kidney failure, your treatment will depend on how far the disease has progressed. In the early stages, your doctor will likely work with you to make medication and lifestyle changes that can help you prevent the kidney damage from worsening. These may include changes like losing weight, quitting smoking and taking fewer over-the-counter medicines, particularly pain relievers. As the disease progresses, you may need to take medications to lower your blood pressure and cholesterol levels and follow a specific diet to reduce the amount of work your kidneys have to do to process your blood. Once you’re experiencing complete kidney failure, your doctor will likely recommend dialysis to remove toxins from your blood. You may also be a good candidate for a kidney transplant which involves surgery to replace your failing kidney with one from a donor.

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