Medical dissolution is recommended as a first-line treatment for struvite uroliths.4 Thus, a veterinary therapeutic canned diet formulated for struvite dissolution was recommended for Stella. The owner was instructed to gradually introduce additional water to the canned diet as needed to achieve a goal USG of <1.020 and to discontinue table foods to maximize diet efficacy. Based on antimicrobial guidelines, initial therapy with amoxicillin (15 mg/kg PO q8h) was instituted while awaiting culture results.5
Four days after initial presentation and initiation of amoxicillin therapy, final urine culture results were positive for Staphylococcus spp susceptible to several antibiotics, including amoxicillin. The owner was instructed to continue treatment with amoxicillin until urolith dissolution was documented, as bacteria in deeper urolith layers may be released during dissolution.6 The veterinary team confirmed with the owner that Stella had successfully transitioned to the recommended diet and that water was being added to the diet as instructed. Clinical signs started to improve with initial treatment.
At the 4-week follow-up appointment, the owner reported strict adherence to the recommended diet and resolution of lower urinary tract signs. Urinalysis showed a USG of 1.018, a pH of 6.3, and no crystalluria. Urine culture results were negative. Recheck abdominal radiographs showed a decrease in the number and size of uroliths, consistent with partial dissolution of struvite urolithiasis. The owner was encouraged to continue the diet and antibiotic treatment previously described.
At the 8-week recheck, continued owner adherence was confirmed. Stella remained clinically normal, and no uroliths were evident on abdominal radiographs. The owner was instructed to continue the therapeutic diet for 4 weeks before gradually transitioning to the previous maintenance diet, as most dogs with infection-associated struvite urolithiasis do not require long-term dietary therapy after successful dissolution. Twelve weeks after initial presentation, antibiotic therapy was discontinued. A final urine culture performed 13 weeks after initial presentation was negative.