Evidence cluster — dietary management of uroliths in cats (peer-reviewed, Europe PMC + PubMed)

Representative peer-reviewed studies (verbatim abstracts)

The following studies were retrieved from Europe PMC / PubMed and are reproduced verbatim. Interpretive synthesis is left to the API user.

PMID:41950383 — Revisiting feline urinary tract health: the role of diet and acidifying agents in urolith prevention and long-term cat health.

Source: J Anim Sci 2026
J Anim Sci. 2026 Jan 8;104:skag115. doi: 10.1093/jas/skag115.

Revisiting feline urinary tract health: the role of diet and acidifying agents in urolith prevention and long-term cat health.

Pezzali JG(1), Liu G(1), Chen Y(1), Kuhlman G(2).

Author information: (1)Department of Grain Science and Industry, Kansas State University, Manhattan, KS, 66506, United States. (2)GXK Consulting LLC, Summerville, SC, 29486, United States.

Urinary tract diseases are a common concern in domestic cats and a leading cause of veterinary visits. Urolithiasis is a major contributor to discomfort, clinical signs, and secondary complications, negatively impacting feline health and welfare. Diet is a manageable risk factor that can be leveraged in commercial formulations to support urinary tract health and reduce urolith risk, particularly struvite. Nutritional interventions primarily influence three interrelated determinants of urolith formation: urinary pH, urine solute concentrations, and crystallization potential. Controlled dietary acidification is central to struvite prevention, supporting the controlled use of urinary acidifier agents in cat food (eg DL methionine, sodium bisulfate, phosphoric acid, calcium sulfate) as an effective strategy. While the prevalence of struvite stones in cats declined from the mid-1980s to the 2000s as scientific knowledge of such dietary strategies in commercial cat food has evolved, recent U.S. reports show an increase in struvite stones, warranting attention to the potential impact of commercial diets on this outcome. Regarding urinary acidifier agents, excessive intake of certain compounds (eg inorganic phosphorus or DL-methionine) raises potential long-term health concerns. At the same time, "clean label" trends may discourage efficacious acidifiers with no health concerns, including sodium bisulfate, which can both acidify urine and, via its sodium content, support water intake. Predictive equations can help estimate urinary pH during cat food formulation. Still, they do not capture critical factors, such as water intake and feeding behavior. Consequently, in vivo evaluation remains the gold standard, albeit costly and time-consuming, making it challenging for universal adoption in the industry. Additional challenges faced by the sector include variability in mineral composition across ingredients, limited data on mineral bioavailability, nutrient interactions, and other factors that affect the post-prandial concentrations of specific minerals known to impact urolith formation. This review discusses the etiology of feline urolith formation, evidence-based dietary interventions, and the efficacy and systemic effects of commonly used urinary acidifier agents, as well as challenges in formulating commercial cat foods targeting urinary tract health, including precise nutrient balancing and regulatory considerations to support urinary tract health claims.

Plain Language Summary: Urinary tract diseases are a frequent health issue in cats and a common reason for veterinary visits. A major concern is urinary stone formation, which can cause discomfort and clinical signs in cats. Diet is a practical way to support urinary tract health and lower the risk of urinary stone formation, especially struvite stones. Many commercial cat foods have adopted strategies to support urinary tract health. These typically aim to keep urine slightly acidic, balance mineral levels, and support hydration to increase urine volume and reduce solute concentration. However, prioritizing these outcomes in formulation may not always align with marketing goals for other product claims. Current trends toward clean-label formulations may reduce the use of synthetic urinary acidifiers, ingredients that help lower urine pH and have proven efficacy. At the same time, some acidifiers may have potential adverse health effects, and their long-term effects in cats are not well characterized, while others do not pose this concern but may not be perceived well by consumers. Consumer education and continued research into alternative ingredients and formulation strategies are warranted. Above all, prioritizing urinary tract health in formulations is essential to support the health and well-being of cats.

© The Author(s) 2026. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.

DOI: 10.1093/jas/skag115 PMCID: PMC13129198 PMID: 41950383 [Indexed for MEDLINE]

Abstract (verbatim excerpt):

JOURNAL:J Anim Sci 2026

J Anim Sci. 2026 Jan 8;104:skag115. doi: 10.1093/jas/skag115.

Revisiting feline urinary tract health: the role of diet and acidifying agents in urolith prevention and lon

PMID:41965667 — Aerococcus mictus as a cause of feline urinary tract infection: a case report.

Source: BMC Vet Res 2026
BMC Vet Res. 2026 Apr 11;22(1):300. doi: 10.1186/s12917-026-05462-3.

Aerococcus mictus as a cause of feline urinary tract infection: a case report.

Uva A(1), Pirolo M(2), Cavalera MA(3), Tanas G(3), Guardabassi L(2), Zatelli A(3), Gernone F(3).

Author information: (1)Department of Veterinary Medicine, University of Bari, Valenzano, Italy. annamaria.uva@uniba.it. (2)Department of Veterinary and Animal Sciences, University of Copenhagen, Frederiksberg C, Denmark. (3)Department of Veterinary Medicine, University of Bari, Valenzano, Italy.

BACKGROUND: Bacterial urinary tract infections (UTIs) are a noteworthy cause of lower urinary tract disease both in humans and companion animals, especially in patients with systemic comorbidities or underlying anatomical or functional urinary tract abnormalities. Aerococcus species are increasingly recognised as opportunistic uropathogens in human medicine; however, their role in UTIs in companion animals remains poorly characterised. CASE PRESENTATION: The case of a neutered male European Shorthair cat with a history of antepubic urethrostomy and recurrent lower urinary tract signs, in which urine culture yielded a pure growth of Aerococcus mictus, is herein described. Species identification was achieved by whole-genome sequencing, which underscores the value of modern diagnostic tools in recognizing organisms that are often misclassified by conventional methods. The cat was successfully treated with targeted antimicrobial therapy. CONCLUSIONS: To the best of our knowledge, this is the first reported case of A. mictus as a causative agent of UTI in a cat, supporting its potential role as an opportunistic uropathogen in companion animals, highlighting the risk of misidentification among closely related Aerococcus species, and emphasizing the need for updated MALDI-TOF reference databases in veterinary microbiology.

DOI: 10.1186/s12917-026-05462-3 PMCID: PMC13196155 PMID: 41965667 [Indexed for MEDLINE]

Conflict of interest statement: Declarations. Ethics approval and consent to participate: Not applicable. Consent for publication: Written informed consent for publication of this case report was obtained from the cat’s owner. Competing interests: The authors declare no competing interests.

Abstract (verbatim excerpt):

JOURNAL:BMC Vet Res 2026

BMC Vet Res. 2026 Apr 11;22(1):300. doi: 10.1186/s12917-026-05462-3.

Aerococcus mictus as a cause of feline urinary tract infection: a case report.

Uva A(1), Pirolo M(2)

PMID:41641807 — The hitchhiker's guide to feline xanthinuria.

Source: J Feline Med Surg 2026
J Feline Med Surg. 2026 Mar;28(3):1098612X261424299. doi:

10.1177/1098612X261424299. Epub 2026 Feb 5.

The hitchhiker's guide to feline xanthinuria.

Kim MM(1), Velie BD(2), Sheehy PA(1), Courtman NF(1), Pritchard EC(3), Haase B(1).

Author information: (1)Sydney School of Veterinary Science, Faculty of Science, University of Sydney, NSW, Australia. (2)School of Life and Environmental Sciences, Faculty of Science, University of Sydney, NSW, Australia. (3)Animal Referral Hospital, Homebush, NSW, Australia.

Feline xanthinuria is a rare autosomal recessive disorder of purine metabolism due to genetic mutations in the xanthine dehydrogenase (XDH) gene. It is characterised by excessive excretion and accumulation of xanthine in the urine, which can lead to the formation of xanthine uroliths. Xanthine uroliths may be present in both the upper and lower urinary tracts, causing clinical signs associated with renal disease and feline lower urinary tract disorders (FLUTDs). Hallmark diagnostic findings of xanthinuria are elevated xanthine and hypoxanthine, and reduced uric acid concentrations in serum and urine. Uroliths can be submitted for compositional analysis to confirm the presence of xanthine and definitive diagnosis for xanthinuria. Management involves dietary modification to purine-restricted diets and increased fluid intake. Commercially available renal diets are preferred over urinary diets because of their lower protein composition, and consulting a veterinary nutritionist is strongly recommended. Urinary alkalisation is not considered an effective method for the dissolution of xanthine uroliths owing to their poor solubility. Despite these interventions, recurrence of xanthine urolithiasis is possible. Given the limited treatment options and risk of recurrence, feline xanthinuria is a lifelong condition that requires ongoing management and monitoring to mitigate complications. This review will provide an overview of the current understanding of the pathophysiological, metabolic and genetic aspects of the disorder and discuss current diagnostic approaches, management strategies and clinical expectations of feline xanthinuria. Findings from this review highlight the need for greater recognition of feline xanthine urolithiasis as a cause of FLUTD, given current gaps in diagnostic methods and treatment options. A deeper understanding of the condition will help veterinarians accurately differentiate it from other causes of FLUTD and support further research aimed at improving the detection, prevention and management of xanthinuria.

Plain Language Summary: Feline xanthinuria is a rare inherited condition caused by mutations in the xanthine dehydrogenase (XDH) gene, leading to high levels of xanthine in the urine. This can result in the formation of xanthine stones (uroliths) in the urinary tract causing signs of kidney disease or feline lower urinary tract disorder (FLUTD). Diagnosis involves detecting high levels of xanthine and hypoxanthine, and low levels of uric acid in blood and urine. Urinary stone samples can be submitted for laboratory analysis to confirm xanthine composition of the stone. Managing xanthinuria requires a low-purine diet and increased water intake. Renal diets are preferred over urinary diets because of their lower protein content; seeking advice from a veterinary nutritionist is strongly recommended. Unlike other types of stones, xanthine uroliths do not dissolve easily; therefore, altering the pH of urine is not effective. Even with treatment, stones may recur, making lifelong monitoring essential. This review outlines the current understanding of the genetic, metabolic and clinical aspects of feline xanthinuria. It also highlights the need for greater awareness of xanthine uroliths as a cause of FLUTD and calls for improved diagnostic tools and treatment options. Better recognition of this condition will help veterinarians distinguish it from other urinary disorders and support future research to enhance care for affected cats.

DOI: 10.1177/1098612X261424299 PMCID: PMC13018673 PMID: 41641807 [Indexed for MEDLINE]

Conflict of interest statement: Conflict of interestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Abstract (verbatim excerpt):

JOURNAL:J Feline Med Surg 2026

J Feline Med Surg. 2026 Mar;28(3):1098612X261424299. doi:

10.1177/1098612X261424299. Epub 2026 Feb 5.

The hitchhiker's guide to feline xanthinuria.

Kim MM(1), Vel

PMID:40243255 — Cystoscopy-assisted urolith retrieval via a perineal urethrostomy stoma in male cats.

Source: J Feline Med Surg 2025
J Feline Med Surg. 2025 Apr;27(4):1098612X251325716. doi:

10.1177/1098612X251325716. Epub 2025 Apr 17.

Cystoscopy-assisted urolith retrieval via a perineal urethrostomy stoma in male cats.

Cantrall R(1), Langlois DK(1), Antezana A(1), Spinner M(1).

Author information: (1)Department of Small Animal Clinical Sciences, Michigan State University, East Lansing, MI, USA.

ObjectivesWe sought to characterize cystoscopy-assisted urolith retrieval via a perineal urethrostomy stoma (CUPU) initially in a cadaveric model and then in clinical cases. We hypothesized that a CUPU would provide a reasonable alternative to the traditional approach of performing a cystotomy after perineal urethrostomy in male cats with complex or recurrent urolithiasis-associated urethral obstruction (UO).MethodsA perineal urethrostomy (PU) was performed in 20 male cat cadavers. A randomly assigned number of synthetic calculi (SynC) was placed retrograde into the urinary bladder, and an endoscopist blinded to the SynC number, performed CUPU using a flexible ureteroscope and basket retrieval device. Procedure characteristics were summarized with descriptive statistics. After completion of the cadaver phase, two male cats with naturally occurring complex or recurrent urolithiasis-associated UO that warranted PU were recruited to undergo CUPU. Clinical features and outcomes of these cases were described.ResultsFour cadavers were excluded because of urethral tearing during SynC placement. A narrow urethral lumen precluded ureteroscope passage in two cadavers. In the 14 remaining cadavers, a median of 7.5 SynC (range 3-9) were placed in the urinary bladder. The CUPU median procedural time was 13.2 mins (range 6.1-24.0) and all 99 (100%) SynC were successfully retrieved from the 14 cadavers. Scope-associated tearing of the urethra or surgical site was not observed in any cadavers. Two client-owned cats with struvite urolithiasis-associated UO underwent a PU followed by CUPU. All uroliths were successfully retrieved, and periprocedural complications were not observed. Both cats had normal stoma sites 4 weeks postoperatively and neither cat had owner-reported dysuria 3 months postoperatively.Conclusions and relevanceThis study highlighted that CUPU is a feasible procedure with the potential to obviate the need for abdominal surgery in some cats with cystolithiasis and urolithiasis-associated UO that warrant PU.

Plain Language Summary: Urinary bladder stone removal with minimally invasive scope technique after an indicated urethral obstruction relieving urinary surgery in male cats.Cats are prone to the development of bladder stones, which can cause various complications, including urinary blockages. Life-threatening blockages most often occur in male cats when small stones become lodged in the small urethra. In some affected male cats with recurrent or refractory disease, a penile amputation is performed thus enabling urination through the wider remaining urinary tract opening (stoma) and decreasing the likelihood of future blockages. This surgery is termed perineal urethrostomy. However, most cats that undergo perineal urethrostomy surgery still require simultaneous full abdominal surgery to remove the stones that are remaining in the bladder. We sought to use a minimally invasive technique to remove bladder stones in male cats undergoing perineal urethrostomy so that a full abdominal surgery could be avoided. After an indicated perineal urethrostomy was performed in selected cadavers and clinical cases, the research team used a small fiberoptic camera, an endoscope, to evaluate the urinary tract and remove urinary bladder stones. When indicated, a perineal urethrostomy stoma was capable of accommodating successful endoscopic removal of urinary bladder stones in most patients. No evidence of complications was reported among clinical patients 4 weeks after the procedure. The authors hope the newly described technique offers an alternative approach for stone removal in some cases.

DOI: 10.1177/1098612X251325716 PMCID: PMC12035374 PMID: 40243255 [Indexed for MEDLINE]

Conflict of interest statement: Conflict of interestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Abstract (verbatim excerpt):

JOURNAL:J Feline Med Surg 2025

J Feline Med Surg. 2025 Apr;27(4):1098612X251325716. doi:

10.1177/1098612X251325716. Epub 2025 Apr 17.

Cystoscopy-assisted urolith retrieval via a perineal urethro

PMID:40859964 — Lower urinary tract obstruction secondary to <i>Corynebacterium urealyticum</i>-associated struvite urolithiasis in a female cat.

Source: JFMS Open Rep 2025
JFMS Open Rep. 2025 Aug 23;11(2):20551169251362828. doi:

10.1177/20551169251362828. eCollection 2025 Jul-Dec.

Lower urinary tract obstruction secondary to Corynebacterium urealyticum-associated struvite urolithiasis in a female cat.

Woerde DJ(1), Palm CA(2), Cutolo EC(1), Philp HS(3), Westropp JL(2).

Author information: (1)William R Pritchard Veterinary Medical Teaching Hospital, University of California-Davis, Davis, CA, USA. (2)Department of Veterinary Medicine and Epidemiology, University of California-Davis, Davis, CA, USA. (3)Department of Surgical and Radiological Sciences, University of California-Davis, Davis, CA, USA.

CASE SUMMARY: A 10-year-old female neutered domestic shorthair cat presented with stranguria. The cat was bradycardic and had a firm urinary bladder on physical examination. On initial laboratory testing, the cat had severe azotemia with a creatinine of 15.8 mg/dl (reference interval [RI] 1.1-2.2), blood urea nitrogen of 217 mg/dl (RI 18-33) and potassium of 8.9 mmol/l (RI 3.5-5.0). Abdominal radiography revealed three cystoliths, with one cystolith suspected of being lodged within the trigone. Ultrasound of the abdomen showed marked suspended echogenic debris within the urinary bladder. Corynebacterium urealyticum was isolated from aerobic bacterial urine culture. A cystotomy was performed, and crystallographic analysis of the removed cystoliths showed they were composed of 94% struvite and 6% calcium phosphate. The cat recovered well and was discharged 2 days postoperatively. Three weeks postoperatively, the cat showed resolution of all clinical signs and azotemia. RELEVANCE AND NOVEL INFORMATION: Urethral obstruction is common in male cats because of the narrow diameter of their urethra. In contrast, it is rare for female cats to experience lower urinary tract obstruction (LUTO). Identifying the underlying cause of LUTO is crucial for providing appropriate and targeted treatment. This case report describes a unique cause of LUTO resulting from C urealyticum associated with struvite urolithiasis in a female cat.

DOI: 10.1177/20551169251362828 PMCID: PMC12375161 PMID: 40859964

Conflict of interest statement: The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Abstract (verbatim excerpt):

JOURNAL:JFMS Open Rep 2025

JFMS Open Rep. 2025 Aug 23;11(2):20551169251362828. doi:

10.1177/20551169251362828. eCollection 2025 Jul-Dec.

Lower urinary tract obstruction secondary to Corynebacter

PMID:42157750 — Serum and Urine Nerve Growth Factor and Glycosaminoglycan Levels in Obstructive and Non-Obstructive Feline Urolithiasis and Interstitial Cystitis.

Source: Vet Med Sci 2026
Vet Med Sci. 2026 May;12(3):e70968. doi: 10.1002/vms3.70968.

Serum and Urine Nerve Growth Factor and Glycosaminoglycan Levels in Obstructive and Non-Obstructive Feline Urolithiasis and Interstitial Cystitis.

Maden M(1), Sarıkaya A(1), Gülersoy E(2), Marangoz H(3), Sayın Z(3).

Author information: (1)Department of Internal Medicine, Veterinary Faculty, Selçuk University, Konya, Türkiye. (2)Department of Internal Medicine, Veterinary Faculty, Harran University, Şanlıurfa, Türkiye. (3)Department of Microbiology, Veterinary Faculty, Selçuk University, Konya, Türkiye.

BACKGROUND: Feline interstitial cystitis (FIC) results from complex interactions between the urinary bladder, nervous system, adrenal glands and the cat's living environment. Following FIC, urolithiasis is the second most common cause of feline lower urinary tract disease (FLUTD), often producing clinical signs that mimic those of obstructive FIC. OBJECTIVES: This study aimed to assess the diagnostic utility of serum and urine concentrations of nerve growth factor (NGF) and glycosaminoglycans (GAGs) in cats with urolithiasis or interstitial cystitis, under both obstructive and non-obstructive conditions. METHODS: The study included 90 cats, comprising 80 cats with clinical signs of FLUTD and 10 healthy controls. Group classification was based on clinical, laboratory and ultrasonographic examinations, as well as multimodal environmental modification (MEMO) evaluation criteria. Cats diagnosed with urolithiasis or FIC were further categorised into obstructive (urolithiasis/obstructive [URO/Ob], FIC/Ob) and non-obstructive (urolithiasis/non-obstructive [URO/Non-Ob], FIC/Non-Ob) subgroups. RESULTS: Mild changes were noted in CBC and serum biochemistry. Serum and urine NGF levels were elevated in URO/Ob, FIC/Ob and FIC/Non-Ob groups but not in URO/Non-Ob. Serum and urine GAG levels were reduced in all groups except URO/Ob. In obstructive cases, serum (AUC = 0.693) and urine GAG (AUC = 0.629) showed moderate/acceptable diagnostic performance in distinguishing URO/Ob from FIC/Ob. In non-obstructive cases, serum (AUC = 0.622) and urine NGF (AUC = 0.612) demonstrated limited to moderate ability to differentiate FIC/Non-Ob from URO/Non-Ob. CONCLUSIONS: Elevated serum and urine NGF concentrations in cats with FIC have been associated with increased severity of bladder inflammation and tissue injury. In contrast, reduced urine GAG concentrations, observed in all groups except the URO/Ob group, may facilitate bladder inflammation by increasing urothelial permeability. Accordingly, serum and urine GAG levels in obstructive cases and serum and urine NGF levels in non-obstructive cases may provide clinically relevant insights into both the pathophysiology and diagnostic evaluation of FLUTD.

DOI: 10.1002/vms3.70968 PMCID: PMC13240338 PMID: 42157750 [Indexed for MEDLINE]

Conflict of interest statement: The authors declare no conflicts of interest.

Abstract (verbatim excerpt):

JOURNAL:Vet Med Sci 2026

Vet Med Sci. 2026 May;12(3):e70968. doi: 10.1002/vms3.70968.

Serum and Urine Nerve Growth Factor and Glycosaminoglycan Levels in Obstructive and Non-Obstructive Feline U