KIDNEY STONES -Etiology-

Conditions that cause kidney stone formation are not always identifiable. However, through certain foods seem to promote stone formation in susceptible persons, researchers do not believe that eating any specific good causes stones to form in persons who seem not to be susceptible.



Hypercalciuria is an inherited condition that is the cause of stones in >50% of affected patients. In these persons, high levels of calcium in the urine cause crystals of calcium oxalate or calcium phosphate to form in the kidneys.

Stones may be more likely to form in a person with a family history of kidney stones. Urinary tract infections, kidney disorders such as cystic kidney diseases, and certain metabolic disorders such as hyperparathyroidism are also linked to stone formation.

Cystinuria and hyperoxaluria are 2 other rare, inherited metabolic disorders that often cause kidney stones. In cystinuria, excessive amounts of the amino acid cystine are excreted in the urine. This can lead to the formation of stones made of cystine. In patients with hyperoxaluria, an excessive quantity of oxalate is produced by the body. This excess is not able to undergo dissolution in the urine, and the crystals settle out and form stones.

Kidney stones develop in more that 70% of persons with a rare hereditary disease called renal tubular acidosis.

Other causes of kidney stones are hyperuricosuria, a disorder of uric acid metabolism, gout, excess intake of Vitamin D, urinary tract infections, and urinary tract obstruction. Certain diuretics or calcium based antacids also may increase risk of kidney stones by increasing the amount of calcium in the urine.
Calcium oxalate stones may also form in persons who have chronic bowel inflammation or who have undergone intestinal bypass or ostomy surgery. As mentioned previously, struvite stones can form in persons who have had a urinary tract infection. Finally, persons who receive the protease inhibitor indinavir are at risk of having kidney stones.