Your Health A-Z

Kidney failure

Kidney failure occurs when the kidneys stop working properly and harmful wastes build up in the body.

Summary

* Kidney failure occurs when the kidneys stop working properly and harmful wastes build up in the body.

* If the kidneys fail, treatment is needed to replace the work they normally do; usually through dialysis or a kidney transplant.

Alternative names

End-stage renal disease (ESRD), renal failure

What is kidney failure?

Kidney failure is a potentially life-threatening disease. Also called renal failure, it is a condition in which the kidneys lose their ability to function properly.

This deterioration of renal function can be sudden or it can develop over a period of time.

To understand the implications of renal failure you need to keep the basic functions of the kidney in mind; namely to remove excess fluid and waste, to maintain the chemical balance of the body and to produce certain important hormones and enzymes. Therefore kidney failure can lead to an overload of fluid in the body, which adds to the workload of the heart, raises blood pressure and could lead to heart failure.

If your kidneys are unable to remove metabolic and other waste products, toxic accumulation of these substances may follow.

The decrease in production of certain hormones may lead to anaemia as well as phosphate, calcium and other electrolyte disturbances. The chemical constitution of your body is a complicated process, in which your kidneys play a pivotal role. If this delicate balance is lost, major organs like the heart and brain are adversely affected.

Some risk factors cannot be controlled like age, male sex and hereditary kidney disease. Others like diabetes and high blood pressure can be treated and may slow down or prevent kidney damage.

Risk factors for patients who already have Chronic Renal Failure include hypertension, diabetes, a high-protein diet and high blood fats like cholesterol and triglycerides. These patients should also avoid analgesics and anti-inflammatory drugs.

Acute Renal Failure must be prevented in high-risk patients – those with chronic diseases which can affect the kidneys, such as diabetes, hypertension and heart disease. Heart attacks can lead to cardiogenic shock and must be treated early. Pregnant patients who suffer from eclampsia, a hypertensive condition, also have a high risk for kidney damage.

What causes kidney failure?

Acute renal failure (ARF) occurs when an abrupt deterioration of renal function develops within hours or days. ARF follows a dramatic decrease in blood flow to the kidneys, or damage to the kidneys or when urine flow from the kidneys is obstructed.

A severe drop in blood pressure or sudden loss of blood may lead to a shutdown of blood flow to the kidneys, which may occur due to major surgery, trauma, a heart attack, major burns or serious infection.

Chronic renal failure (CRF) occurs when the kidney function decreases gradually, but progressively. High blood pressure and diabetes are two of the most important causes of chronic kidney failure.

Other factors causing a slow decline in kidney function include the natural ageing process, race, obesity, atherosclerosis, inherited kidney disorders and the auto-immune disorder lupus erythematosis.

Long-term exposure to certain drugs, e.g. painkillers and toxins can also lead to CRF, including lead and mercury. Avoiding these can help prevent further deterioration of kidney function.

What are the symptoms of kidney failure?

  • Dehydration
  • Increased urination at night
  • Itchy or yellow skin
  • Facial swelling
  • 'Coke' coloured urine
  • Shortness of breath
  • Distended neck veins
  • Fast or irregular heartbeat
  • Nausea, vomiting and tiredness
  • Muscle cramps and confusion
  • Insomnia

How is kidney failure diagnosed?

ARF: Patients who develop ARF are often in hospital for another condition that puts them at risk for the condition. This includes major surgery, heart attack, crush injury and severe burns.

Urine and blood tests are done and the volume of urine produced is monitored. An abrupt rise in the blood levels of urea and creatinine characterises ARF.

Urine production may be slowed down, but often patients continue to pass more than one litre of urine per day. Sophisticated urine and blood tests are done to determine the renal function.

It is important to determine if the patient might have underlying chronic kidney failure that can slowly progress for years, without causing symptoms. In this case, acute deterioration of the chronic condition can be difficult to differentiate from ARF.

Small, scarred kidneys on sonar or special X-rays of the kidneys, suggest the disease is of a chronic nature.

Taking a thorough history, careful physical examination, urine and special tests will help the doctors establish whether the cause is pre-renal, renal or post-renal.

Obstruction of the urine flow is an important post-renal cause and should be excluded because the management is different from the other forms of ARF. Dehydration is a common cause of pre-renal ARF and correcting the patient’s fluid balance is a priority.

CRF: Patients with chronic conditions that are known to cause kidney damage should be monitored for symptoms or signs of renal decline.

Regular examinations, blood pressure checks, urine and blood tests can be done.

Symptoms typically occur late in the disease and CRF is confirmed with blood tests.

Special X-ray and ultrasound tests are also done and small, scarred kidneys are a common finding.

How is kidney failure treated?

Dialysis: Healthy kidneys filter out excess fluid and wastes. The kidneys also produce hormones that keep your bones strong, blood chemically balanced and stimulate your bone marrow to make red blood cells. These cells carry oxygen in your blood to your organs.

When end-stage renal failure occurs, treatment is necessary to replace the work of the kidneys. Dialysis is a life-saving option until a suitable organ donor is found, but it is not a cure for end-stage renal failure.

A patient with end-stage renal failure can be on dialysis for as long as it takes to get a kidney transplant or for the rest of his or her life.

There are two types of dialysis: Haemodialysis and Peritoneal dialysis:

Haemodialysis: Uses a filter, called a dialyzer, which is connected to a machine. A special solution, dialysate and your blood are perfused on opposite sides of a semi-permeable membrane. Your blood travels to the filter through tubes.

Water and solute move from your blood across the membrane to the dialysate. Fluid and waste products are filtered out in this process and the cleaned blood is returned to your body via a different set of tubes.

Peritoneal dialysis: This is a different method of dialysis that uses the inner lining of your abdomen to filter your blood. The most common type is called CAPD, or continuous ambulatory peritoneal dialysis.

A surgeon places a small catheter in your abdomen that stays there permanently. The abdominal cavity is quite big and the lining is called the peritoneal membrane. This membrane contains a big amount of small blood vessels. The catheter is connected to a special cleansing solution, dialysate, via a tube. The solution passes from a sterile plastic bag through the tube and into your abdomen. The dialysate (usually about 2 litres) stays in your peritoneal cavity with the catheter sealed.

Due to chemical gradients, fluid, wastes and chemicals pass from the blood vessels to the solution. No machine is needed and you can be trained to do it yourself at home.

Kidney transplant:

This is an operation in which a kidney is removed from one person (the donor) and implanted into another person (the recipient). Once kidney function deteriorates beyond a certain point, the loss of function tends to become progressively worse. When your kidneys can no longer sustain you, this function can be performed by long-term dialysis. Many people on dialysis, although not all, are suitable candidates for a kidney transplant.

Sometimes an otherwise healthy person needs to have both kidneys removed. An example of when this would be necessary is severe trauma (injury) to both kidneys. Someone like this would be a good candidate for a transplant.

Most potential transplant recipients will be on a dialysis programme while they wait for a suitable kidney to become available. People on a transplant waiting list need to be prepared to come into hospital at short notice.

Once a kidney becomes available for transplantation, a scoring system is used to determine the best recipient of that specific kidney.

Various systems are used but most include factors such as length of time on the waiting list, accuracy of the match between donor and recipient blood groups and tissue typing, and the relative ages of donor and recipient.

What is the prognosis?

Changes have to be made to the patient's life with regard to diet and daily activities, although through effective treatment, most patients lead full and active lives.

Should the kidneys fail, urgent treatment is needed to replace the work they normally do. The treatment options include dialysis or a kidney transplant.

When to call your doctor

If you experience any swelling of the hands and feet, decreased urinary output or dark-coloured urine, sudden confusion or agitation, muscle cramps, shortness of breath or have an abnormal heart beat you should seek medical advice immediately.

How can kidney failure be prevented?

  • Your kidneys need constant flushing. Drink eight glasses of water daily to enable your kidneys to work optimally.
  • Don't abuse alcohol or other drugs, including over-the-counter pain medications such as aspirin, paracetamol, ibuprofen, and other anti-inflammatories.
  • Long term use of aspirin in high dosages can damage your kidneys, so can taking too much paracetamol on one day.
  • If you have diabetes, high blood pressure or other chronic medical conditions, carefully follow your doctor's recommendations to ensure that your kidneys are not put under strain.
  • Avoid long-term exposure to heavy metals. Ongoing exposure to lead, found in certain paints, lead pipes, soldering materials and jewellery, can lead to chronic renal failure.
  • Consult your doctor when you experience any symptoms of possible kidney problems.