Health Guide » 
Topic Overview
What is chronic kidney disease (CKD)?
Chronic kidney disease develops when the kidneys permanently lose most of their ability to remove waste and maintain fluid and chemical balances in the body. This process can develop rapidly—within 2 to 3 months—or slowly, over 30 to 40 years. The severity of chronic kidney disease depends on how well the kidneys filter wastes from the blood (glomerular filtration rate).
In chronic kidney disease, the kidneys have not stopped working altogether but are not working as well as they should. You can live normally with kidneys that are not functioning at 100% or with only one functioning kidney. Dialysis or kidney transplantation is required when kidney function drops to about 15% of normal.
Another type of kidney disease is acute renal failure. It occurs when the kidneys suddenly stop working. It is usually caused by an event that leads to rapid kidney malfunction, such as dehydration, blood loss from major surgery or injury, or the use of certain medications, such as contrast agents used in some X-ray tests, overuse of nonsteroidal anti-inflammatory medications (NSAIDs), and the use of aminoglycoside antibiotics. For more information, see the topic Acute Renal Failure.
What causes chronic kidney disease?
The cause of chronic kidney disease is not always known. However, many conditions and diseases can damage kidneys and lead to chronic kidney disease.
- Diabetes causes about 35% of all chronic kidney disease.
- High blood pressure causes another 30%.
- Glomerulonephritis is the third most common cause of chronic kidney disease.
Other causes include:
- Medication use or overuse.
- Infection and obstruction of the kidneys.
- Inherited genetic diseases, such as polycystic kidney disease.
How will I know if I have kidney disease?
Some people with chronic kidney disease do not have any symptoms. As kidney function declines, symptoms may include:
- Fatigue.
- Frequent headaches.
- Loss of appetite (anorexia).
- Sleep problems (insomnia).
- Itchy skin.
- Frequent urination or urinary retention.
- Nausea or vomiting.
- Swelling or numbness of the hands and feet.
- Darkening of the skin.
- Muscle cramps.
Since chronic kidney disease may not cause symptoms, your health professional may screen you for it if you are at high risk because you have another condition, such as Diabetes or high blood pressure. Screening may be the only way to know whether you have chronic kidney disease.
How will my doctor diagnose kidney disease?
Your health professional will use blood and urine tests to measure changing levels of chemicals in the bloodstream to help determine how well the kidneys are working. Levels of certain chemicals, such as urea and creatinine, begin to increase as kidney function declines.
Other blood tests will be used to keep track of anemia that can be caused by advanced kidney disease.
An ultrasound can measure the size of the kidneys, estimate blood flow to the kidneys, and determine whether urine flow is blocked. In some cases, a kidney biopsy may be needed to determine the cause of chronic kidney disease.
If you are in a high-risk group because you have Diabetes or high blood pressure, screening for chronic kidney disease is recommended. Early diagnosis of chronic kidney disease and appropriate referral to a kidney disease specialist (nephrologist) can help you to control your condition.
What are the stages of chronic kidney disease?
The stages of chronic kidney disease are determined by the glomerular filtration rate (GFR), which measures kidney function. Glomerular filtration is the process by which the kidneys filter the blood, removing excess wastes and fluids. GFR is used to determine how well the kidneys filter blood. A low GFR number indicates poor kidney function.
Stages of chronic kidney disease | ||
Stage | Description | GFR (mL/min/1.73m 2 ) |
0 | Normal kidney function | 120–125 |
1 | Kidney damage with normal or increased GFR | 90 or above |
2 | Kidney damage with mildly decreased GFR | 60–89 |
3 | Moderately decreased GFR | 30–59 |
4 | Severely decreased GFR | 15–29 |
5 | Kidney failure | 15 or less (on dialysis) |
Chronic kidney disease is defined as either kidney damage or glomerular filtration rate (GFR) of less than 60 mL/min/1.73m2 for longer than 3 months.
Kidney damage includes structural abnormalities, such as those seen on X-ray or ultrasound, or abnormal blood or urine laboratory values.
How is kidney disease treated?
Since another condition usually causes chronic kidney disease, the most effective way to treat kidney disease is to treat and manage the disease that caused your kidney damage. Work with your health professional to:
Develop a plan to aggressively treat and control your Diabetes or high blood pressure to slow additional damage to your kidneys.
Prevent diseases or avoid situations, such as medication use, that can cause kidney damage.
Your health professional will use blood and urine tests to regularly monitor your condition. These tests will determine how your kidneys are functioning and whether changes to your treatment plan are needed.
Kidney dialysis or kidney transplant may be needed if end-stage renal disease (ESRD) develops.
What can I expect if I have chronic kidney disease?
Chronic kidney disease is often progressive. If the disease progresses, your symptoms may occur more frequently or become more severe. Work with your health professional to develop a treatment plan to control these symptoms.
Depending on your stage of chronic kidney disease, you may need to make dietary changes to help slow its progression. You may be asked to limit your use of salt or watch how much potassium or phosphorus is in your diet.
In the early stages of this disease, only a small part of the kidney is involved. Some people have destruction of the glomerulus (glomerulonephritis) or renal tubules. Early kidney disease can cause scarring, which interferes with the blood flow to a portion of the kidney (nephrosclerosis).
Over time, if chronic kidney disease is not treated, end-stage renal disease (ESRD) develops. When this occurs the kidneys have been severely damaged and are often replaced with nonfunctional scar tissue.
What are the complications of kidney disease?
Regardless of what causes kidney disease, problems begin to occur when the kidneys cannot adequately filter and remove waste products from the bloodstream. As levels of these waste products begin to increase, other symptoms and complications occur, including:
- Uremic syndrome.
- Anemia.
- Electrolyte imbalances.
- Fluid imbalances, causing swelling (edema).
