Many people with reduced renal function have a kidney disease that will get worse. Health problems will develop and worsen as renal function declines. If your renal function drops below 15 percent, you cannot live long without some form of renal (kidney) replacement therapy—either dialysis or transplantation.
Why do kidneys fail?
Most kidney diseases attack the nephrons, causing them to lose their filtering capacity. Damage to the nephrons may happen quickly, as the result of injury or poisoning, but most kidney diseases destroy the nephrons slowly and silently. Only after years or even decades will the damage become apparent. Most kidney diseases attack both kidneys at the same time.
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.
Diabetes is a disease caused by high levels of glucose (sugar) in the blood, which results when the body can’t make enough insulin or can’t use the insulin. Insulin is needed to maintain healthy glucose (sugar) levels in the blood. If glucose stays in your blood instead of breaking down, it can act like a poison. Over time, diabetes changes the blood vessels in the body, including the blood vessels that deliver blood to the kidneys. When the nephrons don’t get enough blood they are severely damaged. As a result, the blood can’t pass through the kidneys and the nephrons can’t filter wastes from the blood, or perform their other functions. Damage to the nephrons from unused glucose in the blood is called diabetic nephropathy. If you keep your blood glucose levels down, you can delay or prevent diabetic nephropathy. Monitoring your glucose (sugar) level and keeping your glucose (sugar) level in the normal range is the best way to prevent damage to the kidneys.
High Blood Pressure (also called hypertension)
High blood pressure is known as the “silent killer” and can lead to kidney disease. It can also be a sign that your kidneys are already impaired. The damaged vessels cannot filter wastes from your blood as they are supposed to. The only way to know whether your blood pressure is high is to have a health professional measure it with a blood pressure cuff. The result is expressed as two numbers. The top number, which is called the systolic pressure, represents the pressure when your heart is beating. The bottom number, which is called the diastolic pressure, shows the pressure when your heart is resting between beats. Blood pressure for healthy adults should be below 120/80 (expressed as “120 over 80”). In order to get your blood pressure within the target range, your doctor may prescribe blood pressure medication.
Glomerulonephritis is a type of kidney disease that involves the glomeruli. The glomeruli are small, essential structures in the kidneys that supply blood flow to the small units in the kidneys that filter urine, called the nephrons. Glomerulonephritis is when the glomeruli become inflamed and impair the kidney’s ability to filter urine. As a result, the nephrons can’t filter the blood and the kidneys can’t carry out their other functions. There are many causes of glomerulonephritis.
Polycystic Kidney Disease (also called PKD)
Polycystic kidney disease is usually a genetic disease in which many grape-like, fluid filled cysts grow in the kidneys. These cysts slowly take over and replace much of the kidney. This causes reduced kidney function leading to kidney failure. Most patients with PKD have family members with PKD.
Kidney Infection or Pyelonephritis
Pyelonephritis is an infection most often caused by a germ that travels from the bladder to the kidneys. Severe or frequent infections of this type can cause damage to the kidneys leading to kidney failure.
A kidney stone is a hard mass that develops when calcium oxalate or other chemicals in the urine form crystals that stick together. These crystals may grow into stones ranging in size from a grain of sand to a golf ball. Kidney stones can form in the ureters (the tubes that carry urine from the kidneys to the bladder) and block the flow of urine. Then urine collects in the kidneys, which causes pressure and sometimes infection in the kidneys. Over time, this damages the kidneys and causes them to fail.
Systemic Lupus Erythematosus (also called Lupus)
Lupus is an “autoimmune” disease. The immune system, which usually protects the body from disease, turns against the body, causing harm to organs and tissues. The immune system can cause inflammation and swelling of the blood vessels and organs of the body including the kidneys. If the kidneys become involved, they lose the ability to filter wastes out of the blood or carry out their other normal functions.