Nephrolithiasis is characterized by the formation of crystalline aggregates (“kidney stones”) that can develop anywhere along the urinary tract. Kidney stones are common in Western societies; nearly 10% of Americans will develop a symptomatic kidney stone during their lifetime.
The 5 major stone compositions are calcium oxalate, calcium phosphate, magnesium ammonium phosphate (struvite), uric acid, and cystine. Calcium–based stones are the most common, causing more than 75% of cases, and calcium oxalate is the most common type of stone overall. A rare but increasingly recognized cause of nephrolithiasis is the use of the protease inhibitor indinavir in treating HIV patients. Kidney Stone type | Population | Circumstances | Details | Calcium oxalate | 80% | when urine is acidic (low pH) | Some of the oxalate in urine is produced by the body. Calcium and oxalate in the diet play a part but are not the only factors that affect the formation of calcium oxalate stones. Dietary oxalate is an organic molecule found in many vegetables, fruits, and nuts. Calcium from bone may also play a role in kidney stone formation. | Calcium phosphate | ___% | when urine is alkaline (high pH) | | Uric acid | 5-10% | when urine is persistently acidic | Diets rich in animal proteins and purines: substances found naturally in all food but especially in organ meats, fish, and shellfish. | Struvite | 10-15% | infections in the kidney | Preventing struvite stones depends on staying infection-free. Diet has not been shown to affect struvite stone formation. | Cystine | ___% | rare genetic disorder | Cystine, an amino acid (one of the building blocks of protein), leaks through the kidneys and into the urine to form crystals. |
Risk Factors * Male gender. Males are 3 times more likely to develop stones than females. * History of nephrolithiasis. Individuals who have developed a kidney stone have an 80% chance of recurrence within 10