Chronic kidney disease

Chronic kidney disease (CKD) is a long-term condition in which the kidneys don't work as well as they should. In its early stages it usually causes no symptoms at all, and they tend to appear only once the disease is advanced. That's why doctors usually pick it up earlier, through blood and urine tests.

When chronic kidney disease is advanced, the main symptoms are:

• tiredness
• swollen ankles, feet or hands (due to water retention)
• shortness of breath
• nausea
• blood in the urine

Chronic kidney disease (CKD) is most often found through blood and urine tests.

If you're at high risk of developing CKD, you may be screened once a year. Screening may be recommended if you have:

• high blood pressure (hypertension)
• diabetes
• a family history of CKD

You have 2 kidneys, each shaped like a bean and about the size of your fist. They sit on either side of the body, just beneath the ribcage. Their main job is to filter waste products out of the blood and turn them into urine. The kidneys also do several other things:

• help maintain blood pressure
• keep the chemicals in your body at the correct levels, which in turn helps your heart and muscles work properly
• produce the active form of vitamin D, which keeps bones healthy
• produce a substance called erythropoietin, which stimulates production of red blood cells

Chronic kidney disease means the kidneys are less able to carry out these jobs over the long term. Most often it happens because other conditions have damaged the kidneys, and the most common of these are diabetes and high blood pressure.

Chronic kidney disease (CKD) is common, and it's mostly linked to getting older. The older you are, the more likely it is that your kidneys are working less well than they should, to some degree.

It's estimated that about 1 in 5 men and 1 in 4 women between the ages of 65 and 74 has some degree of CKD.

CKD is also more common in people of south Asian origin (those from India, Bangladesh, Sri Lanka and Pakistan) and in black people than in the general population. Part of the reason is that diabetes is more common in south Asian people, and high blood pressure is more common in people of African or Caribbean origin.

There is no cure for chronic kidney disease (CKD), but treatment can slow the disease down or even stop it from getting worse, and it can prevent other serious conditions from developing.

People with CKD have a higher risk of a heart attack, because the disease changes the circulation.

In a minority of people, CKD can lead to kidney failure. You may also hear this called established renal failure (ERF) or end-stage kidney disease. When this happens, the kidneys stop doing their usual work.

To stay alive, people with ERF may need artificial kidney treatment, which is called dialysis, or a kidney transplant.

Read more about treating chronic kidney disease

A kidney transplant from a living donor can be planned ahead, so that the person with chronic kidney disease spends less time on dialysis, or avoids it altogether. This can also give the person receiving the kidney a better long term outcome.

There are 2 types of living kidney donation:

• directed donation: a person gives a kidney to someone they know, such as a family member or a friend
• altruistic kidney donation: a person gives a kidney anonymously to someone they do not know

The best way to lower your chances of developing chronic kidney disease (CKD) is to keep any conditions you already have, such as diabetes and high blood pressure, under careful control.

A few changes to your daily habits can also bring the risk down. These are:

• having a healthy diet
• avoiding drinking excessive amounts of alcohol
• exercising regularly
• avoiding medicines that can damage the kidney

Most people with chronic kidney disease (CKD) have no symptoms, because the body can cope even with a large drop in kidney function.

Put another way, we are born with a lot more kidney function than we need to stay alive. Often, 1 working kidney is enough. That's why a person can give a kidney to someone who needs a transplant.

A change in kidney function is usually found through a routine blood or urine test. If you are diagnosed with kidney disease, you will have regular blood and urine tests to keep track of how your kidneys are working, and treatment tries to keep any symptoms to a minimum.

If the kidneys keep losing function and move towards kidney failure (established renal failure, or ERF), this is usually followed through blood tests and monitoring. If kidney failure does happen, the symptoms may include:

• weight loss and poor appetite
• swollen ankles, feet or hands (because the body is holding on to water)
• shortness of breath
• blood or protein in your urine (you won't notice protein yourself, as it can only be found with a urine test)
• needing to pass urine more often, particularly at night
• insomnia
• itchy skin
• muscle cramps
• high blood pressure (hypertension)
• nausea
• erectile dysfunction in men (not being able to get or keep an erection)

These are general symptoms, and many less serious conditions can cause them. Many of them can be avoided if treatment starts early, before any symptoms appear.

If any of these symptoms worry you, arrange to see your doctor.

Chronic kidney disease is most often caused by other conditions that put a strain on the kidneys. The two most common are high blood pressure (hypertension) and diabetes.

Blood pressure is the pressure your heart creates in your arteries with each pulse. If that pressure stays too high, it can damage the organs of your body. This can lead to heart disease, stroke and worsening of kidney function.

In around 90% of cases of high blood pressure, nobody knows the cause. There does seem to be a link with a person's general health, diet and lifestyle.

These are the known risk factors for high blood pressure:

• age (the risk goes up as you get older)
• family history of high blood pressure (the condition seems to run in families)
• being of African-Caribbean or south Asian origin
• obesity
• lack of exercise
• smoking
• excessive alcohol consumption
• a high amount of salt in your diet
• a high-fat diet
• stress

Hypertension harms the kidneys by putting strain on their small blood vessels. When that happens, the kidneys can't filter properly.

Diabetes is a condition in which the body makes no insulin, or too little of it (type 1 diabetes), or can no longer use insulin effectively (type 2 diabetes).

You need insulin to keep the glucose (sugar) in your blood in check. It stops the level going too high after a meal and too low between meals.

If diabetes is poorly controlled, too much glucose can build up in your blood. That glucose can damage the tiny filters in your kidneys, and then your kidneys find it harder to filter out waste products and fluids.

An estimated 20% to 40% of people with type 1 diabetes will develop kidney disease before they reach 50 years of age. Around 30% of people with type 2 diabetes also show signs of developing kidney damage.

The first sign of diabetic kidney disease is a low level of protein appearing in the urine. So your doctor will ask for a urine test every year, to pick up any kidney disease as early as possible.

Everyone with diabetes should have a kidney check every year. Finding kidney dysfunction early matters because it shows who is at risk of complications, such as eye problems and impotence.

Several other conditions cause chronic kidney disease (CKD) less often. These include:

• glomerulonephritis (inflammation of the kidney)
• pyelonephritis (infection in the kidney)
• polycystic kidney disease (an inherited condition where both kidneys grow larger than normal because masses of cysts slowly form in them)
• failure of the kidneys to develop normally in an unborn baby while it is growing in the womb
• systemic lupus erythematosus (a condition of the immune system where the body attacks the kidney as if it were foreign tissue)
• long-term, regular use of medicines, such as lithium and non-steroidal anti-inflammatory drugs (NSAIDs), including aspirin and ibuprofen
• blockages, for example due to kidney stones or prostate disease

Most people find out they have chronic kidney disease (CKD) through blood and urine tests.

If you are in a high-risk group for developing chronic kidney disease (CKD), you should be screened for it regularly. People who are not in a high-risk group are not normally screened.

Screening once a year is recommended for the following groups:

• people with high blood pressure (hypertension)
• people with diabetes
• people with acute kidney injury caused by medicines such as lithium or NSAIDs such as ibuprofen, kidney stones or an enlarged prostate
• people with cardiovascular disease (conditions that affect the heart, arteries and veins, such as coronary heart disease or heart failure)
• people with a family history of stage 5 CKD (see below for more information about staging) or an inherited kidney disease
• people with diseases that affect several parts of the body and may affect the kidneys, such as systemic lupus erythematosus
• people with blood in the urine (haematuria) or protein in the urine (proteinuria) where there is no known cause

Your doctor can advise you about whether or not you should be screened for CKD.

Most often, kidney disease is diagnosed because a routine blood or urine test shows the kidneys may not be working normally. If that happens, the test is usually repeated to confirm the diagnosis.

An effective way of assessing how well your kidneys are working in chronic kidney disease is to calculate your glomerular filtration rate (GFR). GFR measures how many millilitres (ml) of waste fluid your kidneys can filter from the blood in a minute, so it's given in ml/min. A healthy pair of kidneys should be able to filter more than 90ml/min.

It's difficult to measure GFR directly, so doctors estimate it with a formula. The result is called the estimated GFR, or eGFR. To work it out, a blood sample is taken and the level of a waste product called creatinine is measured. Your age, gender and ethnic group are also taken into account. The result is similar to the percentage of normal kidney function. For example, an eGFR of 50ml/min equates to 50% kidney function.

The following tests are used to detect proteinuria (protein in the urine):

• Urine tests: used to see whether there is blood or protein in your urine
• Albumin and creatinine testing: this is another urine test that compares the amounts of albumin (a protein) and creatinine in your urine. The ratio of the 2 (the albumin:creatinine ratio or ACR) can be used with eGFR to give doctors a more accurate idea of how the kidneys are functioning

Chronic kidney disease (CKD) is described using a 6-stage system based on eGFR levels. The higher the stage, the more severe the CKD.

Stage 1 (sometimes called G1): the eGFR is normal (above 90 or more), but other tests show signs of kidney damage.

Stage 2 (G2): the eGFR has dropped slightly (60 to 89), but this is still considered normal for a young adult.

If you have stage 1 or 2 CKD, you are advised to have an eGFR test every year, so the condition can be watched closely as it progresses.

Stage 3 is split into two, stage 3a (G3a) and stage 3b (G3b). In stage 3a, the eGFR has dropped mildly (45 to 59). This is called a mild to moderate decrease in kidney function, and it should be checked every year. In stage 3b, the eGFR has dropped moderately (30 to 44). This is called a moderate to severe reduction in kidney function, and it should be checked every 6 months.

Stage 4 (G4): the eGFR has fallen severely (15 to 29). By this point you may be having symptoms of CKD. Further tests should be done every 6 months.

Stage 5 (G5): the kidneys have lost almost all of their function (an eGFR below 15). This is known as established renal failure. Further tests should be done every 3 months.

Your GFR can go up and down over time, so one abnormal result does not automatically mean you have CKD. The diagnosis is usually confirmed only when repeated eGFR tests show your eGFR staying lower than normal over 3 months.

Doctors use a few other tests to see how much damage there is to your kidneys:

• kidney scans, such as an ultrasound scan, a magnetic resonance imaging (MRI) scan or a computerised tomography (CT) scan, which check whether there are any unusual blockages in your urine flow (in advanced kidney disease, the kidneys are shrunken and uneven in shape)
• kidney biopsy, where a small sample of kidney tissue is taken so the cells can be looked at under a microscope for damage

These lifestyle changes are known to help lower your blood pressure and keep chronic kidney disease (CKD) under control:

• stopping smoking
• eating a healthy, low-fat, balanced diet
• keeping your salt intake to less than 6g (0.2oz) a day
• not using over-the-counter nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, unless a medical professional advises you to
• keeping your alcohol intake within recommended limits
• losing weight if you are overweight or obese
• doing regular exercise for at least 30 minutes a day, 5 times a week

You can read more about preventing high blood pressure through lifestyle changes.

One of the main ways to slow down kidney damage is to keep high blood pressure under control. Good control protects the kidneys.

People with chronic kidney disease (CKD) should aim to bring their blood pressure below 140/90mmHg. If you also have diabetes, the aim is below 130/80mmHg.

There are many types of blood pressure medicine. The ones used to control high blood pressure in people with CKD are called angiotensin converting enzyme (ACE) inhibitors. They lower blood pressure around the body and reduce the strain on blood vessels, and they also give the kidney extra protection.

ACE inhibitors include:

• ramipril
• enalapril
• lisinopril
• perindopril

Side effects of ACE inhibitors include:

• a persistent, dry cough
• dizziness
• tiredness or weakness
• headaches

Most of these side effects should pass within a few days, though some people keep having a dry cough.

If the side effects of ACE inhibitors are particularly troublesome, you can be given an alternative medicine called an angiotensin-II receptor blocker (ARB). This group of medicines includes:

• candesartan
• eprosartan
• irbesartan
• azilsartan
• olmesartan
• temisartan
• valsartan
• losartan

The side effects of ARBs are uncommon, but can include dizziness.

Both ACE inhibitors and ARBs can reduce kidney function in some people and raise the level of potassium in the blood. So you will need blood tests after you start treatment and whenever the dose changes. If you are on an ACE inhibitor or ARB and you develop a fever/infection or need medicines for other conditions, it's important to ask your doctor whether the ACE inhibitor or ARB needs to be stopped for a while.

People with chronic kidney disease (CKD) have a higher risk of cardiovascular disease, including heart attacks and strokes. Studies have shown this. Some of the risk factors for CKD are the same as those for heart attacks and strokes, such as high blood pressure and high levels of cholesterol in the blood (atherosclerosis).

Statins are a type of medicine used to lower cholesterol levels. Cholesterol narrows the arteries, and this can block the blood supply to the heart (causing a heart attack) or to the brain (causing a stroke). Statins work by blocking the effects of an enzyme in your liver, called HMG-CoA reductase, which the body uses to make cholesterol.

Statins sometimes have mild side effects, including:

• constipation
• diarrhoea
• headaches
• abdominal pain

Occasionally, statins can cause muscle pain, weakness and tenderness. If you notice any of these, contact your doctor. You may need a blood test, or your treatment may need to change.

If you have kidney disease, you may be asked to cut down on the fluid and salt you take each day. Fluid can build up in your body because your kidneys can't get rid of it as well as they used to.

If you are asked to drink less fluid, you must also count the fluid in foods such as soup and yoghurt. Your doctor or dietitian can advise you about this.

The extra fluid that comes with kidney disease often collects in your ankles or around your lungs. You may also be given diuretics (water tablets), such as furosemide, which help your body get rid of the excess fluid.

If you have no fluid retention and nobody has told you to reduce your fluid intake, there's no need to do so. In fact, it could be harmful in some circumstances.

Many people with stage three, four and five CKD develop anaemia, which means you don't have enough red blood cells. The symptoms include:

• tiredness
• lethargy
• shortness of breath (dyspnoea)
• palpitations (awareness of heartbeat)

Anaemia can come from many other conditions too, so your doctor will investigate to rule out other possible causes.

Most people with kidney disease are given iron supplements, because iron is needed to make red blood cells. To boost iron levels, iron may be given as tablets, such as daily ferrous sulphate tablets, or as occasional intravenous infusions.

If this isn't enough to treat the anaemia, you may be started on injections of erythropoietin, a hormone that helps your body produce more red blood cells. These injections are often given into a vein (intravenously) or under the skin (subcutaneously). Examples include epoetin alfa, beta and zeta, darbepoetin and methoxy polyethylene glycol-epoetin beta.

If you have stage 4 or 5 chronic kidney disease, phosphate can build up in your body because your kidneys can't get rid of it. Phosphate is a mineral that, together with calcium, makes up most of your bones. You get it through your diet, mainly from dairy foods. Normally the kidneys filter out any extra phosphate. If phosphate levels rise too much, the body's usual calcium balance can be upset, and this can lead to thinning of the bones and furring of the arteries.

You may be asked to limit the phosphate in your diet. Foods high in phosphate include red meat, dairy produce, eggs and fish. Your doctor or dietitian should be able to tell you how much phosphate you can eat. There is no advantage in cutting down on these foods unless your phosphate level is raised, though. Always ask a healthcare professional before you change your diet.

If eating less phosphate doesn't bring your level down enough, you may be given medicines called phosphate binders. They bind to the phosphate in the food inside your stomach and stop your body from absorbing it.

To work properly, phosphate binders must be taken just before meals. The most commonly used one is calcium carbonate, but there are alternatives that may suit you better.

Side effects of phosphate binders are uncommon, but they include:

• nausea
• stomach ache
• constipation
• diarrhoea
• flatulence (wind)
• skin rash
• itchy skin

If you have chronic kidney disease, your vitamin D levels can run low, and your bones need this vitamin to stay healthy. The reason is that vitamin D from food and sunlight can't be used by the body straight away. Your kidneys have to activate it first.

Many people with kidney failure can carry on with treatment using medicines, and their kidneys keep working well for the rest of their lives.

In a few people, though, kidney disease gets worse until the kidneys stop working, and this becomes life threatening. This stage is called kidney failure, or established renal failure (ERF). It rarely happens suddenly, so there will be time to plan the next stage of your condition. You should talk with your medical team about whether to have dialysis, a kidney transplant or supportive treatment.

You can read more about dialysis and kidney transplants.

If you decide not to have dialysis or a transplant for kidney failure, or they aren't suitable for you, you will be offered supportive treatment. This is also called palliative care.

The aim is to treat and control the symptoms of kidney failure without using dialysis or transplantation. Supportive treatment includes medical, psychological and practical care for both the person with kidney failure and their family. That includes talking about how you feel and planning for the end of life.

Many people choose supportive treatment because they:

• are unlikely to benefit or have quality of life with treatment
• do not want to go through the inconvenience of treatment with dialysis
• are advised against dialysis because they have other serious illnesses that will shorten their life, and the negative aspects of treatment outweigh any likely benefits
• have been on dialysis but have decided to stop this treatment
• are being treated with dialysis, but have another serious physical illness, especially severe heart disease or stroke, that will shorten their life

If you choose to have supportive treatment, your kidney unit will still look after you. Doctors and nurses will make sure you receive:

• medicines to protect your remaining kidney function for as long as possible
• medicines to treat other symptoms of kidney failure, such as feeling out of breath, anaemia, loss of appetite or itchy skin
• help to plan your home and money affairs
• bereavement support for your family after your death

You can read more about bereavement support from CRUSE.

Most of the time, chronic kidney disease (CKD) can't be prevented completely. You can still take steps that lower the chances of it developing.

If you have a long-term condition such as diabetes that could lead to chronic kidney disease, it matters a great deal that you keep it well managed.

Follow your doctor's advice and keep all your appointments for the condition. People with diabetes are advised to have their kidney function tested every year.

Read more about Type 1 diabetes and Type 2 diabetes

A healthy diet helps prevent chronic kidney disease. It lowers the amount of cholesterol in your blood and keeps your blood pressure at a healthy level. Aim for a balanced diet with plenty of fresh fruit and vegetables (5 a day) and whole grains.

Keep the salt in your food to no more than 6g (0.2oz) a day, because too much salt raises your blood pressure. One teaspoonful of salt is about 6g.

Avoid foods high in saturated fat, as they push up your cholesterol level.

Foods high in saturated fat include:

• meat pies
• sausages and fatty cuts of meat
• butter
• ghee (a type of butter often used in Indian cooking)
• lard
• cream
• hard cheese
• cakes and biscuits
• foods that contain coconut oil or palm oil

Some foods high in unsaturated fat can help bring your cholesterol level down. These include:

• oily fish
• avocados
• nuts and seeds
• sunflower oil
• rapeseed oil
• olive oil

Drinking too much alcohol pushes your blood pressure up, and it raises the cholesterol levels in your blood too. So the best way to lower your risk of high blood pressure (hypertension) and chronic kidney disease (CKD) is to stay within the recommended limits for alcohol.

Regular exercise can help lower your blood pressure, and that in turn reduces your risk of developing chronic kidney disease (CKD).

The recommended amount is at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity every week. Cycling or fast walking are good examples.

Chronic kidney disease can sometimes be caused by using non-steroidal anti-inflammatories (NSAIDs) the wrong way, for example by taking too many. Aspirin and ibuprofen are two common NSAIDs.

If you need to take painkillers, follow the instructions that come with them. That can help you avoid kidney damage.

Living with chronic kidney disease can put a strain on you, your family and your friends. It can be hard to talk about your condition, even with people who are close to you.

Learning about the illness often helps. When you and your family understand more about what to expect, you feel more in control, and your lives don't start to feel taken over by kidney disease and its treatment.

Be open about how you feel, and tell your family and friends what they can do to help. But don't feel shy about saying you need some time to yourself, if that is what you need.

Chronic kidney disease can affect your sex life, both through its symptoms and through the stress it brings into your life.

Some couples grow closer after the diagnosis. Others find that their partner is weighed down by worry about how they will cope with the illness. Men and women alike may struggle with body image and self-esteem, and that can put a strain on the relationship.

Try to talk openly with your partner about how you feel. If problems with sex don't get better with time, speak to a counsellor or sex therapist.

People on dialysis often have particular sexual difficulties. Loss of sex drive, in both men and women, and impotence in men are commonly reported.

Treatment is available, but it may take some time and needs commitment from both partners. The first step is to discuss it with your healthcare team.

If you have early stage chronic kidney disease, your fertility is not affected, whether you are a man or a woman. So you need to use contraception unless you want to have a baby.

Later stage kidney disease can change a woman's periods, and that can make it harder to become pregnant. In men, later stage disease can lower the sperm count. Even so, having kidney disease doesn't mean you can't get pregnant or father a child. Both men and women should use an effective method of contraception unless they want to have a baby.

Women who want a baby should talk to their renal specialist, or to an obstetrician who has an interest in kidney disease. Depending on the stage of the kidney disease, there can be risks to both the mother and the baby. Planning the pregnancy helps keep those risks as low as possible, and your healthcare team can advise you about this.

Some remedies you can buy without a prescription may be harmful if you have chronic kidney disease. So check with your doctor before you take any new over the counter medicine.

You're at higher risk of being harmed by certain over the counter remedies if:

• you have advanced kidney disease (stage 4 or 5, or a kidney function below 30% of normal)
• you have mild-to-moderate kidney disease (stage 3 with a kidney function between 30 and 60% of normal) and are elderly with another serious illness, such as coronary heart disease

Below is a list of which over the counter medicines are safe for people with kidney disease and which ones should be avoided. Take it as a guide only. For more detailed advice, talk to your pharmacist, your kidney specialist or your doctor.

If you have chronic kidney disease and get a headache, paracetamol is the safest choice and the best painkiller to use. Avoid the soluble kind, though, because those products are high in sodium.

If your kidney function is less than about 50%, stay away from painkillers that contain aspirin, ibuprofen or similar drugs such as diclofenac. They can make the function of damaged kidneys worse. The one exception is low-dose aspirin of 75mg to 150mg a day, which can be used if a doctor has prescribed it to prevent vascular disease.

You should also avoid ibuprofen if you're taking anti-rejection treatment after a kidney transplant.

Many cough and cold products contain a mixture of ingredients, so if you have chronic kidney disease, read the packaging carefully. Some contain paracetamol, which is safe. Others contain high doses of aspirin, and it's best to avoid those.

Many cold remedies also contain decongestants, which you should avoid if you have high blood pressure. The best way to clear congestion is steam inhalation with menthol or eucalyptus. For a cough, try a simple linctus, or glycerine honey and lemon, to soothe your throat.

If you have muscle or joint pain with chronic kidney disease, the best choice is a topical preparation, which you rub on to the painful area of skin. Avoid tablets containing ibuprofen, or similar drugs such as diclofenac, if your kidney function is below 50%. Ibuprofen gel or spray is safer than ibuprofen tablets, but it isn't completely risk-free, because a small amount of the drug passes through the skin into the bloodstream.

About 1% of people with stage three chronic kidney disease (CKD) go on to develop kidney failure, which is also called established renal failure (ERF). Kidney failure has a major impact on your life and on the lives of those close to you. Most people who are diagnosed with it go through shock, grief and denial before they come to accept their condition.

If you have established renal failure (ERF), you will need to decide between dialysis and a kidney transplant. You may also decide on neither, and choose supportive care instead. These choices should be made together with your doctors and the rest of your care team.

For people who want active treatment for their ERF, a transplant would be the best option. But a transplant is only suitable for about half of all people with ERF, because some have had cancer recently or are not physically fit enough.

Many people have kidney failure that gets worse slowly, along with other serious health problems, and they are usually older. They may choose to avoid dialysis. Supportive care can still allow you to live for some time with a good quality of life.

If you have chronic kidney disease that has reached ERF, a kidney transplant is the best treatment, when it is suitable for you. The new kidney can come from a deceased donor or a living one, and survival rates are now extremely good. About 90% of transplants still work after five years, and many keep working usefully after 20 years. The main reason people wait is that there aren't enough donors.

Over a third of kidney transplants now come from live donors. A kidney from a live donor can be transplanted before dialysis is needed, instead of after a period on dialysis.

Rejection is one major risk after a transplant. This is when the immune system mistakes the donated kidney for a foreign object and attacks it. Strong drugs that suppress the immune system are used to prevent this, and you must take them with great care. They are usually well tolerated, but they can cause side effects, including a higher chance of infections and of some forms of cancer. For this reason, people with a transplant are reviewed regularly in a specialist transplant clinic.

Dialysis can be done at home or in hospital. It filters waste products and extra water out of your blood. But it isn't as efficient as a healthy kidney, so people with kidney failure usually have to limit how much fluid they drink and avoid or cut down on certain foods.

You will also need extra medicines, such as iron supplements, phosphate binders and antihypertensive medicine (this lowers blood pressure). There are 2 types of dialysis: peritoneal dialysis and haemodialysis.

Your abdomen (tummy) has a lining called the peritoneal membrane, and in peritoneal dialysis this lining is used as a filter to remove excess waste and water. If you choose this treatment, a tube (catheter) is put into your abdomen during an operation. Once it's in place, you can drain the dialysis fluid in and out of your tummy yourself.

You won't need to go into hospital for the treatment. But you will have to spend an hour or two each day draining the fluid. There are two ways of doing it. One is four exchanges spaced out through the day, each taking half an hour. The other is to attach yourself overnight to a machine that pumps the fluid in and out for you.

Haemodialysis removes waste products and extra fluid that build up in your body when the kidneys stop working. Your blood is taken out of the body and cleaned in a filter called a dialyser, which is really an artificial kidney. The whole process takes about four hours, and it usually has to be repeated three times a week.

Most people go to hospital for haemodialysis. Some people choose to have the treatment at home instead.

Home haemodialysis gives you more flexibility, but it also brings greater responsibility. You'll need enough space in your home for a dedicated machine and, in most cases, a lot of support from a close family member or friend. Some people choose to have their dialysis at night while they are asleep. Most people who choose home haemodialysis have it every day, so their fluid intake is not as restricted.

During haemodialysis, large amounts of blood have to pass through the machine. For that, the doctors need to reach blood vessels that are big enough. So if you need haemodialysis, you will have a minor operation to join one of the deep arteries to a vein close to the surface of the skin. This join is called a fistula. The operation is done as day surgery. It should be done at least 6 weeks before you need dialysis, because a fistula needs time to mature before it can be used.

Occasionally there isn't enough time to make a fistula before dialysis has to start. When that happens, the team finds a temporary solution, usually an indwelling plastic dialysis catheter. A catheter is a surgical tube put into the body so that fluid can pass through it.

The dialysis team will go through all of these issues with you in detail before any decisions are made.