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Types of Kidney Stones

Kidney stones are comprised of various combinations of compounds. The table below discusses the types of stones and how common each type is.
 
Name of stone
Approximate incidence
Constituents
Calcium oxalate
70 percent of all stones
Calcium, oxalate
Calcium phosphate
10 percent of all stones
Calcium, phosphate
Uric acid
5-10 percent of all stones
Uric acid
Struvite
10 percent of all stones
Calcium, ammonia, phosphate
Cystine
Less than 1 percent of all stones
Cystine
Medication-induced stones
Less than 1 percent of all stones
Composition depends on medication or herbal product (examples include indinavir, ephedrine, guaifenesin, silica)
 
 
Commonly a person develops a mixture of stones (e.g., a combination of calcium oxalate plus calcium phosphate or uric acid stones).
 
View photos of types of kidney stones
 
Stone Composition
 
Chemical analysis of a kidney stone - either one that is caught as it is spontaneously passed into urine or one that is removed during a surgical procedure - allows for precise determination of stone composition.
 
Some observations: 
  • The most common type of stone contains calcium and oxalate.
  • Other stones frequently observed in stone forming individuals are calcium phosphate, uric acid, and, less commonly, struvite (a combination of calcium, ammonia, and phosphate).
  • Struvite stones usually form as a result of urinary tract infections where bacteria produce ammonia that builds up in the urine.
  • Two very rare genetic disorders can also cause people to form stones. One disorder, called cystinuria, causes a person's urine to become saturated with cystine, a derivative of the amino acid cysteine, leading to the formation of cystine stones. People with cystinuria generally begin to form stones in childhood. Another inherited disorder is xanthinuria, which causes xanthine stones.
  • Very rarely, stones can form as a result of taking certain medications or herbal products and the subsequent build-up of chemicals from those products in the urine. Some of these are indinavir, ephedrine, guaifenesin, and products containing silica.
  • Cranberry concentrate in the form of tablets have been associated with calcium oxalate stones.