Kidney Stones

« Win Prize And Cash | Home | Make Extra Money »

By peace | May 15, 2007

Your kidneys are bean-shaped organs, each about the size of your fist. They are located near the middle of your back, just below the rib cage, one on each side of the spine. The kidneys are sophisticated trash collectors. Every day, your kidneys process about 200 quarts of blood to sift out about 2 quarts of waste products and extra water. The wastes and extra water become urine, which flows to your bladder through tubes called ureters. Your bladder stores urine until you go to the bathroom. The wastes in your blood come from the normal breakdown of active muscle and from the food you eat. Your body uses the food for energy and self-repair. After your body has taken what it needs from the food, wastes are sent to the blood. If your kidneys did not remove these wastes, they would build up in the blood and damage your body. In addition to removing wastes, your kidneys help control blood pressure. They also help make red blood cells and keep your bones strong.

Kidney stones are one of the most common disorders of the urinary tract. Kidney stones are a common cause of blood in the urine and pain in the abdomen, flank, or groin. Kidney stones are sometimes called renal calculi. Men tend to be affected more frequently than women. The prevalence of kidney stones rises dramatically as men enter their 40s and continues to rise into their 70s. For women, the prevalence of kidney stones peaks in their 50s. Once a person gets more than one stone, others are likely to develop.

The condition of having kidney stones is termed nephrolithiasis or urolithiasis or renal stone disease. Nephrolithiasis literally means kidney stone-itis while urolithiasis means urinary stone-itis.

A kidney stone is a hard mass developed from crystals that separate from the urine and build up on the inner surfaces of the kidney. Kidney stones may be as small as a grain of sand or as large as a pearl. Some stones are even as big as golf balls. Stones may be smooth or jagged. They are usually yellow or brown. A stone may stay in the kidney or break loose and travel down the urinary tract. A small stone may pass all the way out of the body without causing too much pain. A larger stone may get stuck in a ureter, the bladder, or the urethra. A problem stone can block the flow of urine and cause great pain.

Normally, urine contains chemicals that prevent or inhibit the crystals from forming. These inhibitors do not seem to work for everyone, however, so some people form stones. If the crystals remain tiny enough, they will travel through the urinary tract and pass out of the body in the urine without being noticed.

Kidney stones may contain various combinations of chemicals. The Four major types of kidney stones are:

1. Calcium Stones
Approximately 85% of stones are composed predominantly of calcium compounds. The most common cause of calcium stone production is excess calcium in the urine (hypercalciuria). Excess calcium is normally removed from the blood by the kidneys and excreted in the urine. In hypercalciuria, excess calcium builds up in the kidneys and urine, where it combines with other waste products to form stones. Low levels of citrate, high levels of oxalate and uric acid, and inadequate urinary volume may also cause calcium stone formation.

Calcium stones are composed of calcium that is chemically bound to oxalate (calcium oxalate) or phosphate (calcium phosphate). Of these, calcium oxalate is more common. Calcium phosphate stones typically occur in patients with metabolic or hormonal disorders such as hyperparathyroidism and renal tubular acidosis.

Increased intestinal absorption of calcium (absorptive hypercalciuria), excessive hormone levels (hyperparathyroidism), and renal calcium leak (kidney defect that causes excessive calcium to enter the urine) can cause hypercalciuria. Prolonged inactivity also increases urinary calcium and may cause stones.

Renal tubular acidosis (inherited condition in which the kidneys are unable to excrete acid) significantly reduces urinary citrate and total acid levels and can lead to stone formation, usually calcium phosphate.

2. Struvite Stone
A less common type of stone is caused by infection in the urinary tract. This type of stone is called a struvite or infection stone. A struvite stone may form after an infection in the urinary system. These stones contain the mineral magnesium and the waste product ammonia. Bacteria in the urinary tract release chemicals that neutralize acid in the urine, which enables bacteria to grow more quickly and promotes struvite stone development.

Struvite stones are more common in women because they have urinary tract infections more often. The stones usually develop as jagged structures called “staghorns” and can grow to be quite large.

3. Uric Acid Stone
A bit less common is the uric acid stone. Digestion produces uric acid. If the acid level in the urine is high or too much acid is excreted, the uric acid may not dissolve and uric acid stones may form. Genetics may play a role in the development of uric acid stones, which are more common in men. Approximately 10% of patients with kidney stone disease develop this type of stone. A uric acid stone may form when the urine contains too much acid. If you tend to form uric acid stones, you may need to cut back on the amount of meat you eat.

4. Cystine Stone
Cystine stones are rare. Cystine is an amino acid in protein that does not dissolve well. Cystine is one of the building blocks that make up muscles, nerves, and other parts of the body. Some people inherit a rare, congenital (i.e., present at birth) condition that results in large amounts of cystine in the urine. Cystine can build up in the urine to form a stone. The disease that causes cystine stones runs in families. This condition (called cystinuria) causes cystine stones that are difficult to treat and requires life-long therapy.

Urolithiasis is the medical term used to describe stones occurring in the urinary tract. Other frequently used terms are urinary tract stone disease and nephrolithiasis. Doctors also use terms that describe the location of the stone in the urinary tract. For example, a ureteral stone (or ureterolithiasis) is a kidney stone found in the ureter.

Share and Enjoy: