• 1. Osborne CA, Abdullahi S, Polzin DJ, et al. Current status of medical dissolution of canine and feline uroliths, in Proceedings. 1983 Kal Kan Symp Treatment Small Anim Dis 1984; 5381.

    • Search Google Scholar
    • Export Citation
  • 2. Osborne CA, Lulich JP, Kruger JM, et al. Medical dissolution of feline struvite urocystoliths. J Am Vet Med Assoc 1990; 196: 10511063.

    • Search Google Scholar
    • Export Citation
  • 3. Houston DM, Rinkardt NE, Hilton J. Evaluation of the efficacy of a commercial diet in the dissolution of feline struvite bladder uroliths. Vet Ther 2004; 5: 187201.

    • Search Google Scholar
    • Export Citation
  • 4. Houston DM, Weese HE, Evason MD, et al. A diet with a struvite relative supersaturation less than 1 is effective in dissolving struvite stones in vivo. Br J Nutr 2011; 106:S90S92.

    • Search Google Scholar
    • Export Citation
  • 5. Cannon AB, Westropp JL, Ruby AL. Evaluation of trends in urolith composition in cats: 5,230 cases (1985–2004). J Am Vet Med Assoc 2007; 231: 570576.

    • Search Google Scholar
    • Export Citation
  • 6. Houston DM, Moore AEP. Canine and feline urolithiasis: evaluation of over 50,000 urolith submissions to the Canadian veterinary urolith centre from 1998 to 2008. Can Vet J 2009; 50: 12631268.

    • Search Google Scholar
    • Export Citation
  • 7. Osborne CA, Lulich JP, Nwaokorie E. Feline urolith epidemiology update: 1981 to 2011. DVM Newsmagazine. Available at: veterinarynews.dvm360.com/dvm/Veterinary+news/Feline-urolith-epidemiology-update/ArticleStandard/Article/detail/775263. Accessed Jul 25, 2012.

    • Search Google Scholar
    • Export Citation
  • 8. Lulich JP, Osborne CA. Changing paradigms in the diagnosis of urolithiasis. Vet Clin North Am Small Anim Pract 2009; 39: 7991.

  • 9. Thieman-Mankin KM, Ellison GW, Jeyapaul CJ, et al. Comparison of short-term complications between dogs and cats undergoing appositional single-layer or inverting double-layer cystotomy closure: 144 cases (1993–2010). J Am Vet Med Assoc 2012; 240: 6568.

    • Search Google Scholar
    • Export Citation
  • 10. Gross KL, Becvarova I, Armstrong PJ, et al. Feeding young adult cats: before middle age. In: Hand M, Thatcher K, Remillard R, et al, eds. Small animal clinical nutrition. 5th ed. Topeka, Kan: Morris Animal Institute, 2012; 373387.

    • Search Google Scholar
    • Export Citation
  • 11. Scott WD, Wrigley TJ, Webb KM. A computer model of struvite solution chemistry. Talanta 1991; 38: 889895.

  • 12. Appel SL, Lefebvre SL, Houston DM, et al. Evaluation of risk factors associated with suture nidus cystoliths in dogs and cats: 176 cases (1999–2006). J Am Vet Med Assoc 2008; 233: 18891895.

    • Search Google Scholar
    • Export Citation
  • 13. Weichselbaum RC, Feeney DA, Jessen CR, et al. Urocystolith detection: comparison of survey, contrast radiography and ultrasonographic techniques in an in vitro bladder phantom. Vet Radiol Ultrasound 1999; 40: 386400.

    • Search Google Scholar
    • Export Citation
  • 14. Bly KM, Kruger JM, Kinns J, et al. In vitro comparison of plain radiography, double contrast cystography, ultrasonography, and computer tomography for estimation of cystolith size. Am J Vet Res 2010; 71: 374379.

    • Search Google Scholar
    • Export Citation
  • 15. Lekcharoensuk C, Lulich JP, Osborne CA, et al. Association between patient-related factors and risk of calcium oxalate and magnesium ammonium phosphate urolithiasis in cats. J Am Vet Med Assoc 2000; 217: 520525.

    • Search Google Scholar
    • Export Citation

Advertisement

Efficacy of two commercially available, low-magnesium, urine-acidifying dry foods for the dissolution of struvite uroliths in cats

Jody P. Lulich DVM, PhD, DACVIM1, John M. Kruger DVM, PhD, DACVIM2, Jennifer M. MacLeay DVM, PhD, DACVIM3, Jane M. Merrills DVM, DABVP4, Inke Paetau-Robinson PhD5, Hasan Albasan DVM, PhD6, and Carl A. Osborne DVM, PhD, DACVIM7
View More View Less
  • 1 Minnesota Urolith Center, Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55105.
  • | 2 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.
  • | 3 Hill's Pet Nutrition Center, 1035 NE 43rd St, Topeka, KS 66617.
  • | 4 Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824.
  • | 5 Hill's Pet Nutrition Center, 1035 NE 43rd St, Topeka, KS 66617.
  • | 6 Minnesota Urolith Center, Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55105.
  • | 7 Minnesota Urolith Center, Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55105.

Abstract

Objective—To compare the efficacy and safety of using 2 commercially available, low-magnesium, urine-acidifying dry foods to dissolve sterile struvite uroliths in cats.

Design—Prospective, multicenter, randomized clinical trial

Sample—37 cats with presumed struvite uroliths.

Procedures—Cats were randomly assigned to be fed 1 of 2 low-magnesium, urine-acidifying dry foods (food A or B). For each cat, physical examination, urinalysis, and abdominal radiography were performed weekly to assess treatment response.

Results—32 cats had complete urolith dissolution. Mean ± SD times for a 50% reduction in urolith size (0.69 ± 0.1 weeks) and complete urolith dissolution (13.0 ± 2.6 days) were significantly shorter for cats fed food A, compared with those (1.75 ± 0.27 weeks and 27.0 ± 2.6 days, respectively) for cats fed food B. At study termination, mean ± SD urine pH (6.083 ± 0.105) for cats fed food A was lower than that (6.431 ± 0.109) for cats fed food B. In 5 cats, uroliths did not dissolve and were subsequently determined to be composed of 100% ammonium urate (n = 4) or 100% calcium oxalate (1). Adverse events associated with diet were not observed in any of the cats.

Conclusions and Clinical Relevance—Results indicated that dietary dissolution is safe and effective for eradication of sterile struvite uroliths in cats. Cats fed food A had faster urolith dissolution than did cats fed food B. Lack of a reduction in urolith size at 2 weeks after diet initiation was indicative of misdiagnosis or noncompliance.

Abstract

Objective—To compare the efficacy and safety of using 2 commercially available, low-magnesium, urine-acidifying dry foods to dissolve sterile struvite uroliths in cats.

Design—Prospective, multicenter, randomized clinical trial

Sample—37 cats with presumed struvite uroliths.

Procedures—Cats were randomly assigned to be fed 1 of 2 low-magnesium, urine-acidifying dry foods (food A or B). For each cat, physical examination, urinalysis, and abdominal radiography were performed weekly to assess treatment response.

Results—32 cats had complete urolith dissolution. Mean ± SD times for a 50% reduction in urolith size (0.69 ± 0.1 weeks) and complete urolith dissolution (13.0 ± 2.6 days) were significantly shorter for cats fed food A, compared with those (1.75 ± 0.27 weeks and 27.0 ± 2.6 days, respectively) for cats fed food B. At study termination, mean ± SD urine pH (6.083 ± 0.105) for cats fed food A was lower than that (6.431 ± 0.109) for cats fed food B. In 5 cats, uroliths did not dissolve and were subsequently determined to be composed of 100% ammonium urate (n = 4) or 100% calcium oxalate (1). Adverse events associated with diet were not observed in any of the cats.

Conclusions and Clinical Relevance—Results indicated that dietary dissolution is safe and effective for eradication of sterile struvite uroliths in cats. Cats fed food A had faster urolith dissolution than did cats fed food B. Lack of a reduction in urolith size at 2 weeks after diet initiation was indicative of misdiagnosis or noncompliance.

Contributor Notes

The study was performed and cats were evaluated at the Veterinary Medical Center at the University of Minnesota or the Veterinary Teaching Hospital at Michigan State University.

Supported by a grant from Hill's Pet Nutrition Inc.

Presented as an oral presentation at the American College of Veterinary Internal Medicine Forum, Denver, June 2011.

The authors thank Sarah Davidson, Carmon Koenigsknech, Sharon Steck, Heidi Scheifelbein, and Holly Monroe for technical assistance.

Address correspondence to Dr. Lulich (lulic001@umn.edu).