Midwest Stone InstituteMidwest Stone Institute
Causes And Types Of Stones
Copyright 1995 Health ResponseAbility Systems, Inc.Stones produced within the urinary system are not the disease, but the end product of the disease process. Scientists suggest many different causes or factors in stone formation. These factors include:
1. Age
2. Genetic disorders
3. Occupation
4. Climate
5. Metabolic disturbances
5. Presence of infection
6. Dietary patterns
7. The amount of water consumedHeredity may play an important role in the tendency to form stones. Blacks tend to have far fewer stones than whites. About three males are affected for every female.
Stones occur in more than 70 percent of individuals with the hereditary disease known as renal tubular acidosis. Cystinuria is a prime example of a genetic defect that often results in formation of urinary stones. In this disorder, the body excretes excessive amounts of the amino acid cystine, which is insoluble in urine and may accumulate in the urinary system to form stones.
Another genetic defect that causes stone formation is hyperoxaluria. This metabolic disorder leads to overproduction of the chemical oxalate by the body, and increased excretion of this salt into the urinary tract.
Stones are composed of substances such as calcium oxalate, calcium phosphate, and uric acid. Calcium stones are the most common. In fact, about 90 percent of all urinary stones contain calcium, which dissolves poorly in urine.
Calcium oxalate is the most common crystal found in stones. This organic acid is produced within the body, and it is also taken in through foods such as broccoli, spinach, asparagus, rhubarb, oranges, various berries, apples, grapes, pineapples, cranberries, beer, coffee, tea, cocoa, cola drinks, pepper, and others.
Both calcium and phosphorus, of course, are basic parts of the normal diet needed for bone and cell metabolism. Oxalate, which cannot be broken down by the cells of the body, must be flushed out in the urine.
When too much calcium oxalate accumulates in the urine, crystals form and a kidney stone develops. This imbalance can result from ingestion of certain diuretics or antacids, or from eating foods high in oxalate. Formation of calcium oxalate stones also occurs frequently in individuals who have suffered from chronic inflammation of the bowel, or who have had an intestinal bypass operation.
A urinary stone may consist entirely of one compound, but most stones are a combination of salts. Determining exactly what type of stone an individual has passed and the mechanism by which it was formed can be very important. The physician must have this information in order to recommend rational preventive treatment.
Medical scientists are not always sure just why kidney stones form, or why one person forms them and another person does not. Sometimes anatomical abnormalities predispose a person to stone formation. There is evidence that drinking too little fluid, which can result in dehydration, decreases the amount of urine and increases the concentration of the elements that accumulate to form stones.
Stones may accompany metabolic disturbances that result in excessive levels of calcium in the blood and urine. Sometimes stones occur in conjunction with chronic urinary tract infections or with the misuse of certain medications. The immobilization, for several weeks or longer, of an individual who is subject to stones can be the initiating event in stone formation.
While certain foods may promote formation of stones in susceptible people, scientists do not believe that eating any specific food causes stones to form in healthy individuals. Absorptive hypercalciuria is a condition in which a person's body absorbs calcium from food at an abnormally high rate, and empties the excess calcium through the bloodstream and kidneys into the urine.
This high level of urinary calcium sometimes may cause crystals of calcium oxalate or calcium phosphate to form and grow in the kidneys or urinary tract. In some cases, a person may habitually eat too much food that is high in calcium, resulting in excessive calcium being passed through the kidneys.
Normally, urine contains chemical substances that inhibit the formation of crystals. These inhibitors do not seem to work for everyone, however, and some people form stones even though their urine does not show abnormally high levels of calcium.
Other causes of stone formation are hyperuricosuria (a disorder of uric acid metabolism), gout, overactivity of the parathyroid glands, excessive consumption of vitamin D, urinary tract infection, and blockage of the urinary tract.
For more information call Midwest Stone Institute at
(314) 835-1549
or
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