Most bladder stones can be seen on plain x-rays.

This week, we had several discussions around the clinic about bladder stones in cats and dogs. I thought this might be a good topic, as these often take owners totally by surprise.

Urinary stones can form from many different inorganic compounds and can make trouble anywhere along the urinary tract. Common types include struvite (magnesium-ammonium-phosphate, sometimes still referred to as “triple phosphate”), calcium oxalate (“CaOx,” which come in monohydrate or dihydrate varieties), urate, and cystine. Struvite and CaOx constitute by far the majority of stones seen in cats and dogs. Each type develops based on fairly specific conditions, such as urine pH, the presence of bacteria (struvite in dogs), or a primary disease process (urate with liver disease). In addition, breed-specific mutations may permit large amounts of the precursor compounds that lead to stone formation; this is true of cystine (Newfies, Dachshunds, and English Bulldogs) and urate (Dalmatians). More