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The Kidney Stone WebSite by Roger Baxter
An Educational Resource for Sufferers with Kidney Stones
by Roger Baxter
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Chemical Composition of Kidney Stones

Knowing which one of the several types of chemical composition has caused a suffer's kidney stone to form will allow medical treatment to prevent that particular type of stone and thereby prevent recurrent kidney stone attacks. Therefore it is very important to catch the stone — when and if it is passed — so that it can be chemically analyzed.

Most stones are made up of calcium or a combination of calcium and oxalate. These stones show up quite well on x-rays. Calcium mineral combination stones cannot be dissolved with any known medicine. However kidney stones made up of uric acid are invisible to x-rays, but can sometimes be dissolved with the proper medications.

  • Common Chemical Make Up:
    • calcium phosphate (8%)
    • calcium oxalate (most common: 73%, most opaque)
    • magnesium ammonium phosphate (also called "struvite" - often caused by an infection)
  • Uncommon Chemical Make Up:
    • diammonium calcium phosphate
    • magnesium phosphate
  • Rare Chemical Make Up:
    • cystine (faintly opaque; 1%)
    • urate (lucent - meaning translucent to x-rays; 7%)
    • xanthine

A series of nine magnified PHOTOGRAPHS of these various types of stones is available online from Herring Lab, the company who analyzes more kidney stones than any other — over 125,000 per year.

The southeastern area of the United States is known as the Kidney Stone Belt because of the relative high ratio of people suffering from kidney stones in those states. North Carolina (where this author, a fellow kidney store sufferer happens to live) has more kidney stone cases per capita than any other state. Several factors probably come into play to create this situation. One is the typical southern diet which is high in green vegetables and brewed tea — both of which are high in oxalates. The second is the hot climate which causes increased amounts of perspiration and loss of body fluid. And finally, modern life styles often reduce physical activity.

Together these factors put people at high risk for kidney stones. Oxalate from foods is usually present in urine. The oxalate forms a salt with calcium that has a low soluability factor (it does not dissolve easily; it does precipitate into crystals easily). Even mild chronic dehydration can increase the likelihood of kidney stone formation. Inactivity has been associated with increased kidney stone formation: Russian astronauts in space for long periods have developed kidney stones. Thus a southerner with high levels of oxalate combined with chronic dehydration and a sedentary life style is more likely to suffer from their increased risk of forming kidney stones.

Vitamin C and Vitamin D increase the formation of oxalates during the food digestion processes. (Not only do certain foods contain oxalate, additional oxalates can be formed as a byproduct of the natural metabolic process.)

©1997-2016 Roger Baxter

Latest update March 5, 2016