Kidney disease

Kidney disease

What is kidney disease?

The primary function of the kidneys is to rid the body of the waste produced through the breakdown (metabolism) of protein to an energy form. The main waste product is urea, which is normally passed out of the body in the urine. If your kidneys malfunction, urea builds up in your body, accumulating in the kidneys, bloodstream and elsewhere (azotaemia).

Azotaemia can be mild with no symptoms but, if the waste continues to build up for long enough, your kidney function can begin to fail. When symptoms of kidney failure become apparent (usually when 80% of function has been lost) the condition is known as uraemia.

The symptoms of uraemia include:

Kidney (renal) disease or failure can happen very suddenly or may develop slowly over a period of months or years.

What is acute renal failure?

Acute renal failure is a sudden, severe failure of the kidneys that usually occurs as a result of another disorder. The cause may include:

What are the symptoms of acute renal failure?

Symptoms of acute renal failure usually include:

If you develop acute renal failure you will be treated in hospital, where your intake of food and fluids will be strictly monitored. Most people with acute renal failure recover but kidney function may not return to its previous capacity. Your kidneys should begin to heal within about two to six weeks and improvements will continue for three to 12 months.

What is chronic renal failure?

Chronic renal failure occurs when the kidneys become irreversibly damaged and cannot function properly. This may be caused by:

As with the acute form of the disease, waste products build up in your body, resulting in symptoms of anaemia, fluid imbalance, high blood pressure and movement of calcium out of the bone.

The disease usually progresses through three stages. Initially, there is an unnoticeable decrease in kidney function, due to the fact that the remaining healthy kidney cells compensate for the damaged cells. At this stage it is possible for you to live an active lifestyle for many years. Indeed, it may be years before any symptoms are spotted. Chronic kidney damage is often discovered by accident during routine blood or urine tests.

With increased destruction of your kidney cells, kidney function continues to decline to about a quarter of its capacity. The last stage of chronic renal failure results in the build up of waste matter in the blood when symptoms become apparent (uraemia). These include:

Chronic kidney disease tends to be irreversible. If it is widespread, involving both kidneys, total renal failure may occur. It occurs over time and needs to be treated as soon as it is diagnosed, rather than waiting for symptoms which may take years to present themselves.

If you are experiencing kidney failure you may find that you have to change some aspects of your lifestyle. You will probably need to limit the intake of certain proteins in the diet and increase the intake of carbohydrates such as savoury rice and pasta. A dietitian will give you the best advice to suit your individual needs. Fluid intake is adjusted to maintain the correct water balance in your body.

Kidney dialysis or a kidney transplant may need to be commenced if these measures are not enough to control the disease. However, attending hospital for dialysis can be uncomfortable and time-consuming.

I’ve heard that a form of kidney disease called glomerulonephritis is linked to chest infections. What exactly is it?

The kidney is made up of about a million functional units known as nephrons. These filter waste from microscopic blood vessels that gather together in networks known as glomeruli.

Glomerulonephritis is an acute inflammation of both kidneys simultaneously. It results in damage to the glomeruli. The onset may be insidious and the disease commonly affects children and young adults, with a higher incidence occurring in males.

The cause of the inflammation is due to the body’s response to invading bacteria, especially a streptococcal infection, which is responsible for respiratory (chest and throat) infections.

When such bacteria invades the body, antibodies are produced to destroy them. Sometimes the body’s response is insufficient and millions of clumps of bacteria, locked to defending antibodies, circulate around the body in the blood.

These become lodged on the walls of the tiny blood vessels (glomeruli) that supply blood for filtration to the kidney. This causes severe inflammation and much damage. The inflammation can cause some of the glomeruli to rupture and interferes with filtration. Symptoms include:

Treatment includes rest and regulation of diet and fluids, which may be restricted. Carbohydrates will be encouraged, as this will prevent the body breaking down its stores of protein. Salt will be restricted to reduce the retention of fluid in the body and to reduce the person’s blood pressure. Your dietitian will advise on each particular case.

Medications will also be administered to treat the underlying infection and to encourage the excretion of excess fluid in the body. Dialysis may also be considered to rid the body of excess waste.

Most people with glomerulonephritis associated with streptococcal infection recover with no problems. Only a few progress to develop a chronic form of the disease. The nephrons (kidney cells that filter the blood) become increasing unable to function, resulting in high blood pressure, heart failure and kidney failure. However, the rate at which the disease progresses can vary considerably.

What is diabetic kidney disease?

Diabetic kidney disease is a form of renal failure that happens to some people with insulin-dependent diabetes. The exact cause is unknown but one explanation is that high blood glucose levels in the diabetic person's bloodstream trigger the onset of kidney disease. Another explanation is that this may be the result of the body’s immune response to the insulin.

It causes infection of the kidney; wasting of the kidney cells; and damage to its tiny blood vessels. This causes protein to be released into the urine, which makes diabetic kidney disease quite easy for your doctor or nurse to detect using a urine test.

This form of kidney disease often presents in conjunction with other diabetic complications, including high blood pressure and diabetic eye disease. One unusual symptom of diabetic kidney disease is a recurrent metallic taste in the mouth; otherwise its symptoms are similar to chronic kidney failure.

What is pyelonephritis?

Pyelonephritis is an inflammation of the funnel part of the kidney (known as the pelvis) that collects urine from the kidney itself. It is caused by an infection, which may travel upwards along the urinary tract from the bladder or may arise in the blood. It is more common in females than males. Retention of urine in the bladder is a common cause.

The infection results in destruction of the nephrons (microstructures in the kidney that filter waste from microscopic blood vessels). The outcome depends on the amount of viable kidney tissue left when the infection clears up.

Onset is sudden and may be accompanied by a convulsion in a child. Other symptoms include:

Treatment usually involves drinking lots of water and other fluids to flush the infection out of the kidney. Your doctor will take a urine sample to determine the cause and will prescribe an antibiotic to fight the specific infection.

It is very important that the infection is completely cleared up as it can become chronic and destroy the nephrons, leading to chronic renal failure.

What is polycystic kidney disease?

Polycystic kidney disease is caused by the development of cysts throughout both kidneys. It is congenital (you are born with it), familial (runs in families) and affects both sexes. It does occur in children, although this form is rare. It is more usually seen in adults between the ages of 30 and 50.

The cysts enlarge slowly and cause pressure on the cells in the kidney, eventually damaging them. Symptoms include pain, bleeding and repeated infection. A person with this disorder may go on to develop chronic renal failure, uraemia or cardiac failure.

While polycystic kidney disease is very serious, research continues and there appears to be the possibility of a major breakthrough in this area. In the meantime, it can be treated with dialysis and kidney transplant.

Is chronic nephritis a serious disease?

The answer is yes. Chronic nephritis is a persistent, destructive inflammation of both kidneys that occurs as a result of the body’s production of substances that attack and destroy the kidney cells. Healthy tissue is replaced by useless scar tissue, resulting in reduced kidney function.

Chronic nephritis accounts for well over 60% of deaths in Ireland from terminal kidney failure. However, research has led to some significant advances in recent times.

My friend has been put on water tablets in hospital as the doctors say she has nephrotic syndrome. What is that?

Your friend probably went to her doctor with swelling all over her body, especially around her eyes and ankles and a reduction in the amount of urine passed.

Tests would then have shown a raised level of protein in the urine and a raised level of fat in the blood, which are characteristic of the disorder. The nephrotic syndrome usually develops in people with other kidney problems or diseases in which kidney involvement is secondary. These might include glomerulonephritis, rheumatiod arthritis, diabetes, severe high blood pressure or poisoning or adverse drug reactions.

She may have developed other symptoms, including:

The treatment of the nephrotic syndrome is to rid the body of excess fluid, reduce the protein in her urine and reduce the fat in her blood. She may be given steroids to help the problem, depending on the underlying cause but her doctor will decide on this.

It is likely that she was prescribed the water tablets (diuretics) to help rid her body of the excess fluid and this will make her pass a lot of urine.

Your friend may be placed on a low-salt diet so that fluid is not retained and she may have to eat more food containing protein in order to replace what has been lost.

She should also be careful not to pick up any infections, as the swollen tissue has probably lowered her resistance and will make her more susceptible. Your friend will probably be let home from hospital once her condition has stabilised and she should be encouraged to remain as active as possible. She will also require regular medical check-ups to ensure that her condition continues to improve.

My doctor says that I will need to have dialysis. What will this involve?

In Ireland, about 170 people each year reach the end-stage of renal failure and are in dire need of treatment to replace their non-functioning kidneys.

All suitable patients are placed on dialysis. If they have a reasonably successful response they may continue on this treatment indefinitely or be placed on a list for a kidney transplant.

Dialysis will involve the removal of waste products from your body by passing your blood through a filtration machine that mimics the function of the kidneys. It is an arduous process that needs to be performed on a regular basis for as long as the kidneys are unable to function.

There are two different types of dialysis, peritoneal dialysis and haemodialysis. Peritoneal dialysis would involve placing a tube through the lining of your abdomen (peritoneum) and into your abdominal cavity. This tube can then be left in place for some time.

Dialysis is performed by running a special fluid into your abdomen via the tube and then draining it out a number of hours later. This fluid collects your body’s toxins that would normally be filtered out by healthy kidneys. Some kidney patients find that this form of dialysis can even be performed at home and many choose to carry out the process at night as they sleep.

Haemodialysis is about one-tenth as efficient as having normal kidney function. This involves running your blood through an 'artificial kidney' machine. The blood passes from an artery via a tube through a membrane in the machine. The machine, generally only available in hospital renal units, cleans the blood of its toxins and returns it through a vein to your body via another tube.

Haemodialysis takes a number of hours to complete and must be repeated every few days. This form of dialysis can be particularly hard on you, as it entails regularly travelling to and from hospital for treatment.

A dietitian will advise you on what to eat when you are on dialysis. You will be encouraged to eat high protein food, including meat and chicken. The amount of potassium in your diet will be strictly monitored as it can be harmful to your heart if your take either too much or too little. Potassium is a mineral found in fruit such as bananas, vegetables, milk, chocolate and nuts. Your fluid intake will be monitored carefully as well. Salt will be restricted as it makes the body retain fluid.

There are currently about 400 people in Ireland successfully receiving dialysis treatment. About 230 of these must attend major city hospitals to receive haemodialysis. The remainder filter their blood at home through the use of peritoneal dialysis.

While haemodialysis involves travelling to hospital for treatment, it can be reassuring to have specially-trained personnel available at all times. If you choose to have peritoneal dialysis, you will certainly find that it is more flexible and can be carried out when it suits your own routine.

What exactly is involved in a kidney transplant?

Kidney transplantation involves removing a kidney from one body and resiting in the body of another person. The donor may be living or recently deceased (cadaver donor).

Live donors include a brother, sister or parent with identical blood and tissue types to those of the recipient and the success rate is higher in these cases. They will usually recover quickly from surgery, with no problems. The removal of the kidney from a living donor and the transplantation in the recipient are usually synchronised in adjacent operating theatres to reduce the risk of damage to the kidney.

For cadaver donors, after death the body is kept on a ventilator and the kidneys are ‘harvested’ in an operating theatre. Once removed the kidneys can be transplanted up to 36 hours later. The donations are usually anonymous.The kidneys are kept cool during transport and are brought to Beaumont Hospital, Dublin, where the transplant operations are performed.

Donors must be free of significant disease, such as cancer or serious high blood pressure. Similarly, recipients must not have any diseases that would make a transplant operation dangerous or cause the transplanted kidney to fail. These include:

Recipients must also be able to understand the transplant operation and the responsibilities that go with it. They must not abuse alcohol or drugs and must be willing to follow medical advice.

When a kidney becomes available the surgeon has a very short time to accept it for transplantation, therefore the potential recipient must be available and contactable at all times. This may mean wearing a pager or mobile phone constantly.

A transplanted kidney takes over the functions of the damaged kidneys. The ureter (long, thin tube that transports urine from the kidney to the bladder) of the transplanted kidney is imbedded in the wall of the recipient’s bladder and the kidney is attached to the renal artery and vein to ensure a good blood supply.

The recipient must have regular blood tests and check-ups, and must take imunosuppressant medications for the rest of their lives to ensure that their body does not reject the kidney as a foreign body. A kidney from a cadaver donor usually lasts about 10 years, while those from living donors can last 20 or 30 years. If the kidney fails, it is possible to go back on dialysis and have another transplant.

The Irish success rate is one of the highest in Europe – 90% with kidneys from cadaver donors and over 91% with kidneys from live donors. While the rate of transplantation does not quite keep up with the waiting list, the situation is improving. Patients can expect to wait an average of less than one year for a transplant.

The number of transplants has risen steadily in the last 10 years. In 1990, there were 137 patients transplanted, a rise of 30% on the previous year. In 1995 that figure had risen to 147 and by October 1998 the figure was 133.

Where can I get more information about kidney disease?

You may wish to contact the Irish Kidney Association, which provides support and information to kidney patients, their families and friends. The IKA publishes a magazine and runs educational awareness campaigns about kidney disease. The association offers advice on diet and actively promotes organ donation. The IKA has also opened a state-of-the-art support centre to accommodate families of patients receiving treatment at the National Kidney and Transplant Unit in Beaumont Hospital. To find out more, contact the Irish Kidney Association online at or Tel: LO-CALL 1890 456556.

If you are diagnosed with kidney damage your GP will refer you to a specialist renal unit. There are specialist renal units at the following hospitals in Ireland:

The staff at any of these units should be able to answer any questions you may have.

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