Kidney failure occurs when your kidneys lose the ability to filter waste from your blood sufficiently. It may not cause symptoms in the early stages.
Your kidneys filter your blood and remove toxins from your body. These toxins go to your bladder and are eliminated when you urinate. When this process doesn’t work properly, you can get kidney failure.
If your kidneys can’t function properly, toxins can overwhelm your body. This can lead to kidney failure, which can be life threatening if left untreated.
Keep reading as we break down everything you need to know about kidney failure, including symptoms, stages, treatment, and the typical outlook.
Kidney failure, aka renal failure, is when your kidneys can no longer function effectively. This means they can’t filter waste and toxins from your blood. People with kidney failure have lost 85% to 90% of their kidney function.
Kidney failure may occur due to acute (sudden) or chronic causes.
As a chronic condition, kidney failure is the final stage of chronic kidney disease. Medical professionals also refer to it as end stage renal disease (ESRD) or end stage kidney disease (ESKD).
Stages of chronic kidney disease
Doctors classify CKD into
Doctors measure kidney function using an estimated glomerular filtration rate (eGFR) blood test. Your eGFR helps determine your CKD stage as follows:
| Stage | Categorization | eGFR (milliliters per min) | Description |
|---|---|---|---|
| 1 | normal | greater than 90 | usually no symptoms, but some people may experience swelling, back pain, and changes in urination frequency; doctor may consider medications to treat underlying conditions |
| 2 | mild | 60 to 89 | detectable issues, such as protein in the urine or physical damage to the kidneys, may be more obvious |
| 3 | moderate | 30 to 59 | apparent symptoms, like swelling, back pain and changes in urination frequency; doctor may consider medications to treat underlying conditions |
| 4 | severe | 15 to 29 | complications may include anemia, high blood pressure, and bone disease; doctor will likely develop a treatment plan to slow damage |
| 5 | kidney failure | less than 15 | evident symptoms, such as vomiting and nausea, trouble breathing, and itchy skin; will need regular dialysis or a kidney transplant |
The
Acute kidney failure, aka acute kidney injury (AKI), occurs when your kidneys suddenly stop working properly. Chronic kidney failure occurs over time.
Doctors may also classify acute kidney failure according to its cause:
- Pre-renal: insufficient blood flow to the kidneys
- Intrinsic: a problem within the kidney, such as damage to the glomeruli or tubules, possibly due to toxins or ischemia (lack of oxygen to the kidneys)
- Post-renal: a blockage that prevents fluid from leaving the kidneys, such as stones
Early stage kidney failure often doesn’t cause noticeable symptoms. According to the Centers for Disease Control and Prevention (CDC), about
As kidney disease progresses, or if you experience acute kidney failure, symptoms may include:
- reduced amount of urine
- swelling of your legs, ankles, and feet from fluid retention
- shortness of breath
- trouble sleeping
- muscle cramping at night
- excessive drowsiness or fatigue
- persistent nausea
- confusion
- chest pain or pressure
- seizures
- coma
Early signs of kidney failure
Symptoms of early stage kidney disease may be subtle and hard to identify. They may include:
Kidney failure urine color
The color of your urine doesn’t tell you much about your kidney function until damage to the kidneys has progressed.
Still, urine color changes may be an early indicator of some issues.
| Urine color | Indication |
|---|---|
| clear or pale yellow | well-hydrated |
| dark yellow or amber | dehydrated |
| orange | dehydration or bile in the bloodstream |
| pink or red | blood in the urine or having eaten certain foods, like beets |
| foamy | contains a lot of protein; potentially an indicator of kidney disease |
Kidney failure can result from various causes. According to the National Kidney Foundation, the two most common include high blood pressure and diabetes.
People who are most at risk usually have one or more of the following:
Loss of blood flow to the kidneys
A sudden loss of blood flow to your kidneys can prompt kidney failure. Some causes include:
- heart attack
- heart disease
- scarring of the liver or liver failure
- dehydration
- severe burns
- allergic reactions
- severe infection, such as sepsis
High blood pressure and anti-inflammatory medications can also limit blood flow.
Urine elimination problems
When your body can’t eliminate urine, toxins build up and overload the kidneys. Some cancers can block the urine passageways, such as:
Other conditions can interfere with urination and possibly lead to kidney failure, including:
- kidney stones
- enlarged prostate
- blood clots within your urinary tract
- damage to the nerves that control your bladder
Other causes
Other factors that may lead to kidney failure include:
- a blood clot in or around your kidneys
- heavy metal poisoning
- drugs and alcohol use
- vasculitis, an inflammation of the blood vessels
- lupus, an autoimmune disease that can cause inflammation of many body organs
- glomerulonephritis, an inflammation of the small blood vessels of the kidneys
- hemolytic uremic syndrome, which involves the breakdown of red blood cells following a bacterial infection, usually of the intestines
- multiple myeloma, a cancer of the plasma cells in your bone marrow
- scleroderma, an autoimmune condition that affects your skin
- thrombotic thrombocytopenic purpura, a disorder that causes blood clots in small vessels
- chemotherapy drugs that treat cancer and some autoimmune diseases
- dyes used in some imaging tests
- certain antibiotics
- unmanaged diabetes
People of all ages develop kidney failure, but the risk increases with age. According to the CDC, about
You may have a higher risk if you have:
- diabetes
- high blood pressure
- heart disease
- a family history of kidney failure
The longer you’ve had these conditions, the
In the United States, African Americans are three times as likely to develop kidney failure than white people. Experts suggest this is due to several factors, including genetics, a higher prevalence of risk factors, issues of access to quality care, and other social determinants of health.
Doctors use several tests to diagnose kidney failure. Common tests include:
- Urinalysis: A urine sample can show how much protein or sugar is in your urine. A urinary sediment examination looks for red and white blood cells, high levels of bacteria, and high numbers of cellular casts.
- Urine volume measurements: Measuring urine output can help diagnose kidney failure. Low output may suggest that kidney disease is due to a urinary blockage.
- Blood samples: Blood tests can measure substances filtered by your kidneys, such as blood urea nitrogen and creatinine. A rapid rise in these levels may indicate acute kidney failure.
- Imaging: Tests like ultrasounds, MRIs, and CT scans provide images of your kidneys and urinary tract to identify issues.
- Kidney tissue sample: Doctors use a kidney biopsy to collect and examine tissue samples.
The type of treatment you need depends on the cause and stage of your kidney failure.
Dialysis
Dialysis filters and purifies the blood using a machine to perform the function of the kidneys. Depending on the type of dialysis, you may be connected to a large machine or a portable catheter bag.
Along with dialysis, you may need to follow a low potassium, low salt diet.
Dialysis doesn’t cure kidney failure, but going to regularly scheduled treatments can extend your life.
Kidney transplant
A transplanted kidney can work fully, so you no longer need dialysis.
There’s usually a long wait to receive a donor kidney that’s compatible with your body. If you have a living donor, the process may go more quickly.
Transplant surgery might not be the right treatment option for everyone. It is not always successful.
You must take immunosuppressant drugs after the surgery to prevent your body from rejecting the new kidney. These drugs have their own side effects, some of which can be serious.
You can talk with a doctor about whether you’re a good candidate for a kidney transplant.
Dietary changes
Making certain dietary changes may help prevent kidney failure from progressing.
The guidelines for what you eat will often depend on the stage of kidney disease you have and your overall health. Some recommendations might include:
- Limiting potassium: Suggestions vary considerably on how much potassium people with CKD should consume, but a potassium-restricted diet usually allows up to 2,000 milligrams (mg) per day. Several factors can influence the best target for you, so talk with a doctor about what your goal should be.
- Limiting sodium: Experts recommend lowering sodium intake to 2,000 to 2,300 mg per day, but the National Kidney Foundation suggests that 1,500 mg may be a better target for people with CKD.
- Limiting phosphorus: Try to stay below
1,000 mgTrusted Source of phosphorus. - Following protein guidelines: In early and moderate kidney disease, you might want to cut back on protein consumption. If you’re on dialysis for ESRD, you may need to
eat more proteinTrusted Source .
Beyond these general guidelines, a doctor may also ask you to avoid certain foods.
Lowering alcohol intake
It’s usually okay for people with kidney disease — even those with ESRD on dialysis — to consume alcohol in moderation. However, there can be risks to some people with CKD, especially if they have other chronic conditions.
Beer, ale, and wine also contain large amounts of phosphorus. Severe heart issues and death are possible if your kidneys cannot filter it out.
If you have kidney failure or late-stage kidney disease, a doctor may recommend you limit alcohol. Eliminating alcohol from your diet, if possible, may be best.
Diabetes is the most common cause of kidney failure. About
Without management, high blood sugar can damage your kidneys. The damage can worsen over time.
Diabetic nephropathy, or kidney damage caused by type 1 or type 2 diabetes, is irreversible. Steps to prevent or limit kidney damage can include:
- managing your blood sugar
- managing blood pressure
- taking medications as prescribed
If you have diabetes, a doctor will likely perform regular screenings to monitor for kidney failure. Your risk of diabetic nephropathy
Kidney failure can lead to various complications. These can include:
- anemia
- bone weakness, due to an imbalance of phosphorus and calcium
- edema (fluid retention)
- heart disease
- hyperkalemia (high potassium levels)
- metabolic acidosis (when blood becomes too acidic)
Many people with kidney failure develop secondary complications. These can include:
It’s not possible to know precisely how long a person with kidney failure will live, as it can depend on many factors.
These include:
- the underlying cause
- how well that underlying cause is managed
- any complicating factors, like high blood pressure or diabetes
- stage of kidney disease at diagnosis
- age
The National Kidney Foundation says that a person on dialysis can expect to live for an average of 5 to 10 years as long as they follow their treatment. Some people live for more than 20 or 30 years.
Once you reach ESRD, you will need dialysis or a kidney transplant to live. Missing even one dialysis treatment can decrease your life expectancy.
Proper treatment and healthy lifestyle changes may improve your outlook.
You can take steps to lower the risk of kidney failure.
Follow directions when taking over-the-counter medications. Taking doses that are too high, even of common drugs like aspirin, can create high toxin levels quickly. This can overload your kidneys. Chronic use of certain medications, like nonsteroidal anti-inflammatory drugs (NSAIDs), can lead to kidney failure.
Many kidney or urinary tract conditions lead to kidney failure without prompt treatment.
You can help lower your risk of kidney failure by:
- eating a balanced diet
- maintaining a moderate weight
- taking prescribed and over-the-counter medications as directed and not taking more medication than is safe
- keeping conditions, such as diabetes and high blood pressure, well managed and following a doctor’s advice
Kidney failure can develop suddenly or from long-term damage. Possible causes of kidney failure can include diabetes, high blood pressure, and kidney trauma.
Chronic kidney disease progresses through five stages, ranging from mild to complete kidney failure. Symptoms and complications increase as the stages progress.
If you have kidney failure, you can work with a doctor to determine the best treatment options.
