Kidney stones can be composed of different substances, but the most common ones (80% of stones) consist of calcium salts, mostly in the form of calcium oxalate and calcium phosphate.[1] Less common kidney stones may form from other substances such as medications, struvite, uric acid, or cystine.[2] Kidney stones tend to occur more frequently in men, with an incidence of 10% compared to 5% in women.[3][4]
When a stone is dislodged from the kidney and enters the ureter (the tube that connects the kidney to the bladder), it often causes significant pain by irritating the urether, and sometimes by blocking the normal flow of urine. While most stones pass on their own, they may also block the urinary tract, requiring treatment or surgery for removal. (Most stones are small, <6mm, and pass on their own; larger stones tend to require procedures for removal.)
References
- ^Coe FL, Parks JH, Asplin JRThe pathogenesis and treatment of kidney stones.N Engl J Med.(1992-Oct-15)
- ^Evan APPhysiopathology and etiology of stone formation in the kidney and the urinary tract.Pediatr Nephrol.(2010-May)
- ^Johnson CM, Wilson DM, O'Fallon WM, Malek RS, Kurland LTRenal stone epidemiology: a 25-year study in Rochester, Minnesota.Kidney Int.(1979-Nov)
- ^Hiatt RA, Dales LG, Friedman GD, Hunkeler EMFrequency of urolithiasis in a prepaid medical care program.Am J Epidemiol.(1982-Feb)