Not true about `Struvite Stones' is -

Ans. is 'd' ie Usually seen in acidic urine Struvite stone tends to grow in alkaline urine* esp. when proteus organisms are present which split urea to ammonia". Types of Renal Calculus a) Calcium oxalate calculus (Most common*) - they have hard, small and jagged surface b) Phosphate calculus - calcium phosphate but can be combined calculus* ie Calcium amnomium magnesium phosphate also k/a struvite stones. - smooth and diy white and soltitary*. - seen in alkaline urine esp with proteus infection which split urea to ammonia. - this type of calculus may enlarge to fill all or most of the renal collecting system forming a staghorn calculus*. c) Uric acid and urate calculus - these are radioluscent* - Form in acidic urine - Most responsive to lithotripsy d) Cystein stones uncommon, seen in cystinuria - appear only in acidic urine* - they are pink to yellow when first removed but they change colour to a greenish hue when exposed to air. extremely hard stones - are relatively resistant to fragmentation by ESWL e) Xanthine calculi - are radioluscent* - are secondary to a congenital deficiency of xanthine oxidase f) Indinavir calculi Indinavir is a protease inhibitor used in AIDS patients. It results in calculi in --6% pt. who use. indinavir. Indinavir calculi are radioluscent. Rare Calculi Silicate stones - associated with the long term use of antacids containing silica Triamterene stones associated with antihypeensive medications containing trimterene are radioluscent