Bladder stones form when the amount of mineral present in the urine is high enough that the mineral is unable to remain dissolved. Instead, the minerals fall out of solution and become crystals, which, in turn, will coalesce into a stone. Different characteristics of the urine -- such as how acidic or basic the pH level is -- can make certain minerals more likely to precipitate into bladder stones. Some diseases can cause increased amounts of minerals to accumulate in the urine. Diet can also play a role. In addition, urinary tract infections can lead to struvite stone formation, as can different abnormalities in a cat's anatomy and metabolism.
Each bladder stone type has predisposing factors that cause certain cats to form that type repeatedly. Cats who develop cystine bladder stones, for example, usually have a genetic inability to absorb the cystine mineral within the kidney.
