Cystinuria is a genetic defect in the kidney tubules; it can affect dogs, humans, and a few other species. Normal kidneys filter the amino acid cystine and do not allow it to go into the urine. In individuals with cystinuria, this filtering action fails, and cystine passes into the urine, where it can form crystals and/or stones (uroliths). If stones form, they can block the urethra and obstruct urinary flow, especially in males.
There are a variety of stones and crystals that can affect our dogs. I often get inquiries on how to treat stones when diagnosed during a veterinarian visit. The first question I ask is, “What type of crystal or stones was found?” Each type of crystal or stone is addressed in two very different approaches.