Kidney stones, medically known as renal calculi, may appear at any time in life. While these stones may be painful, they rarely cause permanent harm. Small stones often pass out of the body undetected. Kidney stones are formed inside the kidney of varying substances and may be attributed to a number of causes.
Calcium
Most small kidney stones are composed of calcium and oxalate or calcium and phosphate. They are often the result of excess calcium, which can occur for several reasons. Some individuals absorb too much calcium from the foods they eat, causing it to wind up in the urine. Chronic use of calcium-based antacids can also cause small calcium stones in the kidney. Diuretics are responsible for some cases. The National Kidney and Urologic Diseases Information Clearinghouse explains that some individuals are vulnerable to kidney stones when they eat a high level of dietary oxalates. Consumption of a large amount of peanuts, rhubarb, sweet potatoes, spinach, beets or chocolate can induce a small kidney stone in these individuals. Other foods may also precipitate the development of calcium stones in susceptible people.
Cystine
Some small kidney stones are made of cystine, an amino acid. MayoClinic.com explains that some individuals have an inherited disorder that causes their kidneys to collect too much of this amino acid for excretion. Cystine has a tendency to crystallize, causing kidney stones.
Uric Acid
Excess uric acid in the urine is responsible for some small kidney stones. This can happen when the person is chronically dehydrated due to hot weathe, poor fluid intake, ill health or strenuous, extended physical activity. Gout, a disorder in which the body does not properly metabolize uric acid, is often to blame for uric acid stones in the kidney. A diet that contains more protein than the body needs can also cause this type of stone.
Struvite
Struvite, a mineral, is responsible for some kidney stones. These are usually the result of a bacterial infection, such as a urinary tract infection. To form these stones, the bacteria attaches to urea, an end product of protein metabolism, forming a small stone. These small stones can grow quite large if they are not excreted soon after formation. According to MedlinePlus, a website of the National Institutes of Health, struvite stones are more common in women.
