Chronic kidney disease (CKD) means that your kidneys are not working as well as they did before. Several conditions can cause chronic kidney disease. The severity can vary, but most cases are mild or moderate, occurring in the elderly, do not cause symptoms and do not progress to kidney failure. People with any stage of CKD are at increased risk of developing heart disease or stroke. This is why it is important to detect even mild CKD, as the treatment can not only slow the progression of the disease, but also reduces the risk of developing heart disease or stroke. A separate leaflet in this series called "mild to moderate chronic kidney disease," is more appropriate if you have chronic kidney disease mild or moderate (stage 1, 2 or 3 CKD).
On this page
- Understanding the kidneys and urine
- What is chronic kidney disease?
- How is chronic kidney disease diagnosed?
- How common is chronic kidney disease?
- What causes chronic kidney disease?
- What are the symptoms of chronic kidney disease?
- Do I need more tests?
- What is the treatment for chronic kidney disease?
- What is the outlook (prognosis)?
- More help and information
Understanding the kidneys and urine
Both kidneys are the sides of the upper abdomen (loins) behind the intestines, and each side of the spine. Each kidney is about the size of a large orange, but bean-shaped.
One of the great arteries – renal artery – supplies blood to each kidney. The artery is divided into many small blood vessels (capillaries) in the entire kidney. On the outside of the small blood vessels kidneys are grouped together to form structures called glomeruli.
Each glomerulus is like a filter. The structure of the glomerulus allows waste products and a little water and salt to pass from the blood into a small canal called a tubule. The liquid remaining at the end of each tubule is called urine. Urine passes through a tube called the ureter leading from each kidney to the bladder. Urine is stored in the bladder until he fainted when going to the bathroom.
The main functions of the kidneys are:
- Filter waste products from the blood, which are excreted in urine.
- Helps to control blood pressure – in part by the amount of water passing outside the body such as urine and in part by the production of hormones involved in controlling arterial pressure.
- Make a hormone called erythropoietin (EPO), which stimulates the bone marrow to produce red blood cells. This is necessary to prevent anemia.
- Help keep various salts and chemicals in the blood at the right level.
What is chronic kidney disease?
ERC means that your kidneys are diseased or damaged in some way, or are aging. As a result, the kidneys can not function as well as they did before. Thus, the various functions of the kidney, as described in the previous section, may be affected. A number of conditions can cause chronic kidney disease (see below).
Some terms explained:
- Chronic means ongoing (permanent or long-term). This does not mean bad as some think. You may have a mild chronic disease. Many people have mild CKD.
- Renal means in relation to the kidney.
- Chronic kidney failure is a term that is sometimes used, but means the same as ERC. ERC is a better term than the word failure means that the kidneys have stopped working completely. In most cases this is not so ERC. In most people with CKD not only a mild to moderate reduction of renal function, which usually causes no symptoms, and kidneys have not "failed."
- Acute renal failure means that the function of the kidneys is affected quickly – within hours or days. For example, the kidneys may enter acute renal failure if you have a serious blood infection that can affect the kidneys. This is in contrast with CKD where decreased kidney function is very gradual – in months or years. Acute renal failure is not addressed further in this article.
How is chronic kidney disease diagnosed?
A simple blood test can estimate the volume of blood that is filtered by the glomeruli in the kidneys over a given period of time. This test is called the glomerular filtration rate (GFR). A normal EGFR than 90 mL/min/1.73 m or more. If any of the glomeruli (tiny filters in the kidneys) filter not normal, the kidney is said to have reduced or impaired renal function.
The eGFR test involves a blood test that measures a chemical called creatinine. Creatinine is a breakdown product of muscle. Creatinine is normally removed from the blood by the kidney. If your kidneys are not working as well and the glomeruli are filtering the blood than normal creatinine level in the blood increases.
The GFR is calculated based on your age, sex and level of creatinine in the blood. An adjustment in the calculation is necessary for people with Afro-Caribbean origin.
CKD is diagnosed by the EGFR and other factors, and is divided into five stages:
|Stage Chronic Kidney Disease||EGFR mL/min/1.73 m|
|Step 1: eGFR shows normal renal function, but it is known to have kidney damage or disease. For example, you may have a little protein or blood in the urine, a kidney abnormality, kidney inflammation, etc.||90 or more|
|Step 2: slight decrease in renal function and is already known to have kidney damage or disease. People with a GFR of 60-89 with no known kidney damage or disease is not considered to have chronic kidney disease (CKD).||60 to 89|
|Step 3: moderately reduced renal function. (With or without known renal disease. For example, an older person with kidney aging may have reduced renal function without a specific known renal disease.)||45-59 (3A)
30 to 44 (3B)
|Step 4: severe reduction in renal function. (With or without known renal disease.)||15 to 29|
|Step 5: very severe renal function decline. This is sometimes called end stage renal failure or established renal failure.||Less than 15|
Note: it is normal for the TFG to change slightly from one measurement to another. In some cases, these changes may actually be large enough to move from one stage of CKD and then back again. However, as long as your eGFR is getting progressively worse, is the average value is more important.
Who has the estimated glomerular filtration rate test?
The eGFR blood test is commonly done as a routine part of monitoring people with kidney disease or conditions that can affect the kidneys, such as diabetes or high blood pressure. Also often done as a routine test in many medical situations. If you are found to have CKD then the eGFR test is usually done at regular intervals to monitor renal function.
How common is chronic kidney disease?
About 1 in 10 people have some degree of CKD. It can occur at any age and the different conditions can lead to CKD. It becomes more common with age and is more common in women.
Although about half of those 75 years and older have some degree of chronic kidney disease, most of these people do not actually have kidney disease, with normal aging kidneys.
Most cases of chronic kidney disease are mild to moderate.
What causes chronic kidney disease?
Several conditions can cause permanent damage to the kidneys and / or affect the function of the kidneys and lead to CKD. Three common causes in the UK, which probably account for about 3 out of 4 cases of chronic kidney disease in adults, are:
- Diabetes. Diabetic kidney disease is a common complication of diabetes.
- High blood pressure. High blood pressure untreated or poorly treated is one of the leading causes of CKD. However, CKD can also cause high blood pressure, such as the kidney plays a role in the regulation of arterial pressure. Nearly nine out of ten people with CKD stages 3-5 have high blood pressure.
- Aging kidneys. There seems to age-related decrease in renal function. About half of those 75 years and older have some degree of CKD. In most of these cases, the ERC not advance beyond the moderate stage unless other kidney problems develop, such as diabetic kidney disease.
Other less common conditions that can cause CKD include glomerular diseases, such as glomerulonephritis (inflammation of the glomeruli in the kidneys) – renal artery stenosis (narrowing), hemolytic uremic syndrome, polycystic kidney disease, blockages in the flow urine, induced by drugs and toxins induced kidney damage, kidney infections and repeated. However, this list is not complete and there are many other rare causes.
What are the symptoms of chronic kidney disease?
It is unlikely that you feel unwell or have symptoms of mild to moderate CKD – ie, stages 1-3. (However, there may be symptoms of an underlying condition such as kidney pain with certain kidney disorders.) CKD is diagnosed by the eGFR test before symptoms develop.
Symptoms tend to develop when it becomes severe CKD (stage 4) or worse. Initial symptoms tend to be vague and nonspecific, such as feeling tired, have less energy than usual, and not just feel good. With more severe CKD, symptoms may occur:
- Trouble thinking clearly.
- A lack of appetite.
- Weight loss.
- The dry and itchy skin.
- Muscle cramps.
- Fluid retention causing swelling of the feet and ankles.
- Swelling around the eyes.
- Need to urinate more often than usual.
- Being pale due to anemia.
- Feeling ill.
If renal function decreases to stage 4 or 5 then several other problems can develop. For example, anemia, and an imbalance of calcium, phosphate and other chemicals into the bloodstream. These can cause various symptoms, such as fatigue due to anemia, and thinning bones or fractures due to imbalance of calcium and phosphate. Renal failure (stage 5) is eventually fatal if not treated.
Do I need more tests?
As mentioned, the eGFR test is done to diagnose and monitor the progression and severity of CKD. For example, should be done routinely at least once a year in those with stages 1 and 2 CKD and more often if you have stage 3, 4 or 5 CKD.
You may have routine testing of urine dipstick occasionally for the presence of blood and protein in urine. Furthermore, blood tests may be performed from time to time to monitor their blood level of chemicals such as sodium, potassium, calcium and phosphate. The need for other tests and then depends on several factors and your doctor will advise. For example:
- Ultrasonography of the kidneys or a kidney biopsy may be recommended if certain conditions are suspected kidney. For example, if you have a lot of protein or blood in the urine, if you have pain that seems to come from a kidney, etc.
- A scan or biopsy is not required in most cases. This is because most people with chronic kidney disease have a known cause of renal function, such as a complication of diabetes, high blood pressure or aging.
- If CKD progresses to stage 3 or worse than other tests can be done. For example, blood tests for anemia and altered level of parathyroid hormone (PTH). PTH is involved in controlling the blood level of calcium and phosphate.
What is the treatment for chronic kidney disease?
The treatment for most cases of chronic kidney disease is usually made by doctors. This is because most cases are mild to moderate (stages 1-3) and require no special treatment. Your GP may refer you to a specialist if you develop stage 4 or 5 CKD, or at any time if you have problems or symptoms that require specialized research.
Research studies have shown that, in many people, treatment in the early stages of CKD can prevent or delay progression through eventual kidney failure.
The goals of treatment are:
- If possible, the treatment of any underlying renal disease.
- Prevent or slow the progression of CKD.
- Reduce the risk of developing cardiovascular disease.
- Relieve symptoms and problems caused by CKD.
The treatment of any underlying renal disease
There are several conditions that can cause CKD. For some of them may have specific treatments for that particular condition. For example, a good glucose control in people with diabetes, controlling blood pressure in persons with high blood pressure, antibiotics for people with recurrent kidney infections, surgery for people with an obstruction to urine flow, etc
Preventing or delaying progression of chronic renal disease
Once the ERC has developed, in many cases tends to worsen gradually over months or years. This can happen even if an underlying cause has been treated. You should be checked from time to time by their GP or nurse to monitor renal function (GFR). It will also give advice on how to treat and prevent or delay the progression of CKD. This usually includes:
- Controlling blood pressure. The most important treatment to prevent or slow the progression of CKD, regardless of the underlying cause, is to keep your blood pressure under control. Most people with chronic kidney disease who require medication to control their blood pressure. Your doctor will give you a target blood pressure level to aspire. This is usually Hg below 130/80 mm, and even less in some circumstances.
- Review of medicines. Some medicines can affect the kidneys as a side effect that can make CKD worse. For example, if you have CKD should not take anti-inflammatory medication unless directed by a doctor. You may also need to adjust the dose of certain medications you can take if your chronic kidney disease worsens.
Reducing the risk of cardiovascular disease
People with chronic kidney disease are at increased risk of cardiovascular disease, such as heart disease, stroke and peripheral vascular disease. People with chronic kidney disease are actually twenty times more likely to die from cardiovascular disease related to the problems of kidney failure. This is why reducing any other cardiovascular risk factor is so important. See separate leaflet called 'Preventing Cardiovascular Disease "for more details. Briefly, this typically includes:
- Good control of blood pressure (and blood glucose levels if you have diabetes).
- Medications to lower your cholesterol level – necessary in many cases.
- Where appropriate, to address the lifestyle factors of risk. This means that:
- Stop smoking if you smoke and if you drink too much alcohol cut.
- Eat a healthy diet that includes low salt intake.
- Keep your weight under control and waist.
- Take regular physical activity.
If you have high levels of protein in the urine, then you may be advised to take medication, even if your blood pressure is normal. A type of drug called an angiotensin converting enzyme (ACE) inhibitors (eg, captopril, enalapril, ramipril, lisinopril) has proven beneficial for some people with chronic kidney disease, reducing the risk of cardiovascular disease and may prevent further worsening of their kidney function.
Relief of symptoms and problems caused by chronic kidney disease
If severe CKD may need treatment to combat various problems caused by renal dysfunction. For example:
- Anemia can develop which may require treatment with iron or erythropoietin ("EPO") – a hormone normally produced by the kidneys.
- Imbalances of calcium or phosphate in the blood may need treatment.
- You may be advised about the amount of liquid to drink, and how much salt to take.
- Other dietary advice can be given which can help control factors such as the level of calcium and potassium in your body.
If end-stage renal failure develops, you may need kidney dialysis or a kidney transplant to survive.
People with CKD stage 3 or worse should get a flu shot every year, and have a single immunization against pneumococcus. People with chronic kidney disease stage 4 should be vaccinated against hepatitis B.
What is the outlook (prognosis)?
CKD stages 1-3 (mild to moderate) are common and most cases occur in older people. It tends to get worse gradually over months or years. However, the rate of progression varies from case to case, and often depends on the severity of the underlying condition. For example, some kidney diseases can cause kidney function to deteriorate relatively quickly. However, in most cases CKD progresses very slowly. Only a small number of people with chronic kidney disease progresses to end stage renal disease (stage 5 CKD) requiring dialysis or a kidney transplant.
For many people with CKD exists a much higher risk of developing serious cardiovascular disease to develop end-stage renal failure.
In short …
- attention to the control of blood pressure
- thorough review of drugs to ensure that only employees are the ones who put least strain on the kidneys
- address the factors that reduce the risk of developing cardiovascular disease
can make a big difference in your attitude.
More help and information
National Kidney Federation
The Point, Coach Road, Shireoaks, Worksop, Nottinghamshire S81 8BW
Helpline: 0845 601 0209 Web: www.kidney.org.uk