How your kidneys work

Why Are the Kidneys So Important?

Most people know that a major function of the kidneys is to remove waste products and excess fluid from the body. These waste products and excess fluid are removed through the urine. The production of urine involves highly complex steps of excretion and re-absorption. This process is necessary to maintain a stable balance of body chemicals.

The critical regulation of the body's salt, potassium and acid content is performed by the kidneys. The kidneys also produce hormones that affect the function of other organs. For example, a hormone produced by the kidneys stimulates red blood cell production. Other hormones produced by the kidneys help regulate blood pressure and control calcium metabolism.

The kidneys are powerful chemical factories that perform the following functions:

• remove waste products from the body
• remove drugs from the body
• balance the body's fluids
• release hormones that regulate blood pressure
• produce an active form of vitamin D that promotes strong, healthy bones
• control the production of red blood cells

There are two kidneys, each about the size of a fist, located on either side of the spine at the lowest level of the rib cage. Each kidney contains up to a million functioning units called nephrons. A nephron consists of a filtering unit of tiny blood vessels called a glomerulus attached to a tubule. When blood enters the glomerulus, it is filtered and the remaining fluid then passes along the tubule. In the tubule, chemicals and water are either added to or removed from this filtered fluid according to the body's needs, the final product being the urine we excrete.

The kidneys perform their life-sustaining job of filtering and returning to the bloodstream about 200 quarts of fluid every 24 hours. About two quarts are removed from the body in the form of urine, and about 198 quarts are recovered. The urine we excrete has been stored in the bladder for anywhere from 1 to 8 hours.

What Are Some of the Causes of Chronic Kidney Disease?

Chronic kidney disease is defined as having some type of kidney abnormality, or "marker", such as protein in the urine and having decreased kidney function for three months or longer.

There are many causes of chronic kidney disease. The kidneys may be affected by diseases such as diabetes and high blood pressure. Some kidney conditions are inherited (run in families). Others are congenital; that is, individuals may be born with an abnormality that can affect their kidneys. The following are some of the most common types and causes of kidney damage.

Diabetes is the leading cause of kidney disease.

High blood pressure (also known as hypertension) is another common cause of kidney disease and other complications such as heart attacks and strokes.

Glomerulonephritis is a disease that causes inflammation of the kidney's tiny filtering units called the glomeruli.

Polycystic kidney disease is the most common inherited kidney disease. It is characterized by the formation of kidney cysts that enlarge over time and may cause serious kidney damage.

Kidney stones are very common, and when they pass, they may cause severe pain in your back and side.

Urinary tract infections occur when germs enter the urinary tract and cause symptoms such as pain and/or burning, but they sometimes spread to the kidneys, and they may cause fever and pain in your back.

Drugs and toxins can also cause kidney problems.

How is Chronic Kidney Disease Detected?
Early detection and treatment of chronic kidney disease are the keys to keeping kidney disease from progressing to kidney failure. Some simple tests can be done to detect early kidney disease. They are:

1.A test for protein in the urine. Albumin to Creatinine Ratio (ACR), estimates the amount of a albumin that is in your urine. An excess amount of protein in your urine may mean your kidney's filtering units have been damaged by disease. One positive result could be due to fever or heavy exercise, so your doctor will want to confirm your test over several weeks.

2.A test for blood creatinine. Your doctor should use your results, along with your age, race, gender and other factors, to calculate your glomerular filtration rate (GFR). Your GFR tells how much kidney function you have. It is especially important that people who have an increased risk for chronic kidney disease have these tests. You may have an increased risk for kidney disease if you:

• are older
• have diabetes
• have high blood pressure
• have a family member who has chronic kidney disease.