Why Do kidneys fail?

Most kidney diseases attack the nephrons, causing them to lose their filtering capacity. Damage to the nephrons may happen quickly, often as the result of injury or poisoning. But most kidney diseases destroy the nephrons slowly and silently. It may take years or even decades for the damage to become apparent.

The two most common causes of kidney disease are diabetes and high blood pressure. If your family has a history of any kind of kidney problems, you may be at risk for kidney disease.

Diabetic nephropathy
Diabetes is a disease that keeps the body from using sugar as it should. If sugar stays in your blood instead of breaking down, it can act like a poison. Damage to the nephrons from unused sugar in the blood is called diabetic nephropathy. If you keep your blood sugar levels down, you can delay or prevent diabetic nephropathy.

High blood pressure
High blood pressure can damage the small blood vessels in your kidneys. The damaged vessels cannot filter poisons from your blood as they are supposed to.

Your doctor may prescribe blood pressure medication. A group of blood pressure medicines called ACE inhibitors appears to give extra protection to the kidneys in patients with diabetes.

Inherited and congenital kidney diseases
Some kidney diseases result from hereditary factors. Polycystic kidney disease (PKD), for example, is a genetic disorder in which many cysts grow in the kidneys. PKD cysts can slowly replace much of the mass of the kidneys, reducing kidney function and leading to kidney failure.

Some kidney problems may show up when a child is still developing in the womb. Examples include autosomal recessive PKD, a rare form of PKD, and other developmental problems that interfere with the normal formation of the nephrons. The signs of kidney disease in children vary. A child may grow unusually slowly, may vomit often, or may have back or side pain. Some kidney diseases may be "silent" for months or even years.

If your child has a kidney disease, your child's doctor should find it during a regular checkup. Be sure your child sees a doctor regularly. The first sign of a kidney problem may be high blood pressure, a low number of red blood cells (anemia), or blood or protein in the child's urine. If the doctor finds any of these problems, further tests may be necessary, including additional blood and urine tests or radiology studies. In some cases, the doctor may need to perform a biopsy--removing a piece of the kidney for inspection under a microscope.

Some hereditary kidney diseases may not be detected until adulthood. The most common form of PKD was once called "adult PKD" because the symptoms of high blood pressure and renal failure usually do not occur until patients are in their twenties or thirties. But with advances in diagnostic imaging technology, doctors have found cysts in children and adolescents before any symptoms appear.

Other causes of kidney disease
Poisons and trauma, for example a direct and forceful blow to your kidneys, can lead to kidney disease.

Some over-the-counter medicines can be poisonous to your kidneys if taken regularly over a long period of time. Products that combine aspirin, acetaminophen, and other medicines such as ibuprofen have been found to be the most dangerous to the kidneys. If you take painkillers regularly, check with your doctor to make sure you are not putting your kidneys at risk.

How do kidneys fail

Many factors that influence the speed of kidney failure are not completely understood. Researchers are still studying how protein in the diet and cholesterol levels in the blood affect kidney function.

Acute renal failure
Some kidney problems happen quickly, like an accident that injures the kidneys. Losing a lot of blood can cause sudden kidney failure. Some drugs or poisons can make your kidneys stop working. These sudden drops in kidney function are called acute renal failure (ARF).

ARF may lead to permanent loss of kidney function. But if your kidneys are not seriously damaged, acute renal failure may be reversed.

Chronic renal failure
Most kidney problems, however, happen slowly. You may have "silent" kidney disease for years. Gradual loss of kidney function is called chronic renal failure or chronic renal disease.

End stage renal disease
The condition of total or nearly total and permanent kidney failure is called end-stage renal disease (ESRD). People with ESRD must undergo dialysis or transplantation to stay alive.

What are the signs of kidney disease?

People in the early stages of kidney disease may not feel sick at all. The first signs that you are sick may be general: frequent headaches or feeling tired or itchy all over your body.

If your kidney disease gets worse, you may need to urinate more often or less often. You may lose your appetite or experience nausea and vomiting. Your hands or feet may swell or feel numb. You may get drowsy or have trouble concentrating. Your skin may darken. You may have muscle cramps.

What happens if my kidneys fail completely?

If your kidneys stop working completely, your body fills with extra water and waste products. This condition is called uremia . Your hands or feet may swell. You will feel tired and weak because your body needs clean blood to function properly.

Untreated end-stage renal disease may lead to seizures or coma and will ultimately result in death. If your kidneys stop working completely, you will need to undergo dialysis or kidney transplant.

Dialysis
The two major forms of dialysis are hemodialysis and peritoneal dialysis. In hemodialysis, your blood is sent through a machine that filters away waste products. The clean blood is returned to your body. Hemodialysis is usually performed at a dialysis center three times per week for 3 or 4 hours.

Transplantation
A donated kidney may come from an anonymous donor who has recently died or from a living person, usually a relative. The kidney that you receive must be a good match for your body. The more the new kidney is like you, the less likely your immune system is to reject it. Your immune system protects you from disease by attacking anything that is not recognized as a normal part of your body. So your immune system will attack a kidney that appears too "foreign." Special drugs can help trick your immune system so it does not reject a transplanted kidney.

Points to remember

• Your kidneys are vital organs, keeping your blood clean and chemically balanced.
• The progression of kidney disease can be slowed, but it cannot be reversed.
• End-stage renal disease (ESRD) is the total loss of kidney function.
• Dialysis and transplantation can extend the lives of people with ESRD.
• Diabetes and high blood pressure are the two leading causes of kidney failure.
• You should see a nephrologist regularly if you have renal disease.
• If you are in the early stages of renal disease, you may be able to save your remaining renal function for many years by
  • Controlling your blood sugar.
  • Controlling your blood pressure.
  • Following a low-protein diet.
  • Maintaining healthy levels of cholesterol in your blood.
  • Taking an ACE inhibitor if you have diabetes.