Stone formed in alkaline urine is:

Struvite stones (infection stones) - Composed of calcium, ammonium, magnesium phosphate (Triple phosphate stones). Tend to grow in alkaline urine, especially with Proteus infection and fill whole of the pelvi-calyceal system, forming staghorn calculi. Formed In high urinary concentration of ammonia. More common In women (Increased susceptibility for UTI) Increased tendency to form struvite calculi Is seen In: Foreign body In the urinary tract (Foley's catheter) and neurogenic bladder / Bladder dysfunction / Bladder outlet obstruction.