What is chronic kidney disease?

Having chronic kidney disease means that for some time your kidneys have not been working the way they should. Your kidneys have the important job of filtering your blood. They remove waste products and extra fluid and flush them from your body as urine.

When your kidneys don't work right, wastes build up in your blood and make you sick. Chronic kidney disease is also called chronic renal failure or chronic renal insufficiency.

There are five stages of chronic kidney disease:

• Stage 1
• Stage 2
• Stage 3
• Stage 4
• Stage 5

How are the stages of kidney disease determined?

The stages of chronic kidney disease are determined mostly by the estimated glomerular filtration rate (eGFR). Glomerular filtration is the process that the kidneys use to filter the blood, removing excess wastes and fluids. The eGFR is a number that shows how well the kidneys filter the blood. It's one way to measure kidney function. Your doctor will also use a test that measures the amount of protein in your urine.

The eGFR is often calculated using a formula that includes a person's age, sex, and serum creatinine (say "kree-AT-uh-neen") levels. The lower the eGFR number, the worse the kidney function. This number is an estimate. It may not be a good measure of kidney health in some people, such as the very young or very old, amputees, or people who have obesity.

What does each stage mean?

Stage 1 (eGFR 90 or above)

There is kidney damage without symptoms.

• Your doctor will try to find the cause of your kidney disease and may begin treatment.
• You'll work with your doctor to manage other health problems, such as diabetes and high blood pressure.
• You'll see your doctor regularly to check how well your kidneys are working.

Stage 2 (eGFR 60–89)

There is a mild decline in kidney function.

• Your doctor will estimate how quickly kidney disease is progressing.
• You'll work with your doctor to manage other health problems, such as diabetes and high blood pressure.
• You'll see your doctor regularly to check how well your kidneys are working.

Stages 3a (eGFR 45–59) and 3b (eGFR 30–44)

In stage 3a, there is a mild to moderate decline in kidney function. In stage 3b, there is a moderate to severe decline in kidney function.

• Your doctor may check for problems caused by kidney disease. These include anemia and bone disease. You'll begin treatment if needed.
• You'll see your doctor regularly to check how well your kidneys are working.

Stage 4 (eGFR 15–29)

There is a severe decline in kidney function.

• You'll work with your doctor to decide what type of treatment you want if kidney failure develops.
• You'll continue treatment and get tested to see how well your kidneys are working.

Stage 5 (eGFR below 15)

There is kidney failure.

• You'll start dialysis, have a kidney transplant, or choose conservative kidney management.
• You'll continue to see your doctor for treatment and testing.

What are the symptoms?

Most people don't have symptoms early on. This is called the "silent" phase of the disease. But symptoms can start to appear a few months after your kidneys have stopped working as well as they should. Symptoms vary depending on the stage of kidney disease.

Stages 1 and 2

Most people don’t have symptoms at these stages. But your doctor may notice signs when testing for kidney damage or other health conditions. These signs could include:

• Swelling of your hands or feet, high blood pressure, a urinary tract infection, and protein in your urine.
• Kidney damage that shows up in an ultrasound, CT scan, MRI, or kidney biopsy.

Stage 3

You may not have symptoms yet. But this stage is when they may start to appear. Symptoms may include:

• Swelling in your hands or feet.
• Urinating more or less often than usual.
• Urine that is foamy or darker in colour than usual.
• Feeling weak and tired.
• Muscle cramps.
• Trouble sleeping.

Stage 4

Symptoms at this stage may include:

• High blood pressure.
• Anemia.
• Bone disease.
• Feeling weak and tired.
• Swelling in your arms or legs.
• Muscle cramps.
• Feeling sick to your stomach or vomiting.
• Loss of appetite.

Stage 5

Symptoms at this stage may include:

• Feeling weak and tired.
• Feeling sick to your stomach or vomiting.
• Loss of appetite.
• Trouble breathing.
• Changes in skin colour.
• Producing little or no urine.
• Swelling in your arms, hands, legs, or feet.
• Headaches.
• Muscle cramps.

How is it treated?

Chronic kidney disease is usually caused by another condition. So the first step is to treat the disease that is causing kidney damage.

Diabetes and high blood pressure cause most cases of chronic kidney disease. If you keep your blood pressure and blood sugar in a target range, you may be able to slow or stop the damage to your kidneys. Losing weight and getting more exercise can help. You may also need to take medicines.

Chronic kidney disease is a complex problem. You will probably need to take a number of medicines and have many tests when you have kidney disease. To stay as healthy as possible, work closely with your doctor. And take your medicines exactly as your doctor says to.

Lifestyle changes are an important part of your treatment. Taking these steps can help slow down kidney disease and reduce your symptoms. These steps may also help with high blood pressure, diabetes, and other problems that make kidney disease worse.

• Be active. For many people, walking is a good choice. Try for at least 2½ hours a week.
• Follow a diet that is healthy for your kidneys. A dietitian can help make an eating plan with the right amount of salt (sodium), protein, and fluids.
• If you smoke, try to quit. If you can't quit, cut back as much as you can. Smoking can make chronic kidney disease worse. If you need help quitting, talk to your doctor about stop-smoking programs and medicines. These can increase your chances of quitting for good.
• Avoid medicines that can harm your kidneys. These include non-steroidal anti-inflammatory drugs (NSAIDs). Examples of these are ibuprofen and celecoxib. Let your doctor know all of the prescription and over-the-counter medicines, vitamins, and herbs you take. And talk to your doctor before you take anything new.
• Avoid or limit alcohol, marijuana, or other drugs. If you need help decreasing your use, talk to your doctor.

Go to all your appointments and follow-up visits. Your doctor will use blood and urine tests to regularly check how well your kidneys are working and decide if you need changes in your treatment plan.

What happens if kidney disease gets worse?

When kidney function falls below a certain point, it's called kidney failure. Kidney failure affects your whole body. It can cause serious heart, bone, and brain problems and make you feel very ill. Untreated kidney failure can be life-threatening.

When you have kidney failure, you will probably have three choices: Start dialysis to filter wastes and extra fluid from your blood, get a new kidney (transplant), or conservative kidney management. All of these treatments have risks and benefits. Talk with your doctor to decide which would be best for you.