Which of the followings renal stones may be large and still be asymptomatic for years: March 2011

Ans. C: Staghorn Phosphate calculus may enlarge to fill most of the collecting system, forming a staghorn calculus. Even a very large straghorn calculus may be clinically silent for years until it signals its presence by hematuria, urinary infection or renal failure Renal calculi: Calcium stones (calcium oxalate and calcium phosphate) makes up 75-85% of the total renal calculi Uric acid stones are radiolucent Uric acid stones are MC in men Struvite stones: - Occur mainly in women or patients who require chronic bladder catheterization - Result from UTI with urease producing bacteria (proteus spp.) - Grow in infected urine Cysteine stones are hard to break in ESWL