In the last few years, struvite stones have taken a back seat to calcium oxalate as the most commonly found stones found in cats, but lab reports suggest that struvite may soon reclaim its stone throne.

Jodi Westropp, DVM, PhD, DACVIM, discussed these findings at the American Board of Veterinary Practitioners (ABVP) meeting in Long Beach, Calif.

During several sessions, Westropp presented cases of urolithiasis and nephroliths submitted to the G.V. Ling Urinary Stone Analysis Laboratory in Colorado. She also shared her experience with diagnostic tools and treatment options for feline urinary tract disease and urged practitioners to send stones in for evaluation.

“All stones should be submitted for quantitative analysis, whether it is the first or fourth stone episode for the patient,” Westropp said. “If it’s worth cutting out, it’s worth submitting,” she added. “Layer-by-layer analysis is necessary to fully understand the formation of the stone and help in prevention strategies, which should include any other disease processes that may be present, including obesity.”

Many pet owners Westropp encounters are willing to go the extra mile to discover root causes for stones, despite the additional diagnostic tests such investigations may require. “When you have clients interested in this, it’s up to you to stay apprised of the latest techniques [and treatment options] for stone removal,” she said.

Using case-specific examples, Westropp discussed the pros and cons of different treatment techniques — from anesthetizing cats and literally shaking stones loose (a technique referred to as voiding urohydropropulsion) to utilizing laser lithotripsy and cytoscopes during surgery.

For dogs, struvite stones are usually caused by urinary tract infections and therefore do not usually reappear. In rare cases, however, struvite stones in dogs are sterile and might require dietary management, Westropp added.

Regardless of removal technique, complete abdominal radiographs should be taken prior to recovery to ensure that all stones have been successfully removed from the lower urinary tract. “Imaging of the entire urinary tract is essential” so that clinicians can rule out the possibility of additional stones, Westropp explained. Although strides have been made to combat what Westropp described as a frustrating disease, research in dietary and drug management continues.