Analysis of canine urolith submissions to the Canadian Veterinary Urolith Centre, 1998-2014.

Understanding urolith trends and risk factors is important for understanding urolithiasis, which is a common problem in dogs. This study evaluated 75 674 canine cystolith submissions to the Canadian Veterinary Urolith Centre between 1998 and 2014. Struvite and calcium oxalate uroliths comprised 80.8% of all uroliths, with calcium oxalate outnumbering struvite. There were significant increases in the proportions of calcium oxalate, mixed and cystine uroliths, and significant decreases in struvite, urate, silica, and calcium phosphate carbonate over the study period. Breeds associated with increased risk of calcium oxalate urolithiasis tended to be small breeds, while those that were at increased risk of struvite urolith formation were larger breeds. Dalmatians were at increased risk of forming both urate and xanthine uroliths while Scottish deerhounds had a remarkably high association with cystine urolithiasis. Males were more likely to form calcium oxalate and metabolic uroliths and females were more likely to develop struvite and mixed uroliths.

Analyse des soumissions d'urolithes canins au Canadian Veterinary Urolith Centre, 1998­2014. Il est important de comprendre les tendances et les facteurs de risque des urolithes pour comprendre l'urolithiase, qui est un problème fréquent chez les chiens. Cette étude a évalué 75 674 soumissions d'urolithes canins au Canadian Veterinary Urolith Centre entre 1998 et 2014. Les urolithes de struvite et d'oxalate de calcium représentaient 80,8 % de tous les urolithes, et le nombre de soumissions d'oxalate de calcium dépassait celui des soumissions de struvite. Il y avait des hausses importantes dans les proportions d'oxalate de calcium, des urolithes mixtes et de cystine et des baisses importantes de la struvite, de l'urate, de la silice et du carbonate de phosphate de calcium pendant la période à l'étude. Les races associées à un risque accru d'urolithiase d'oxalate de calcium étaient surtout des petites races tandis que celles qui présentaient un risque accru de formation d'urolithes de struvite étaient les grandes races. Les Dalmatiens présentaient un risque accru de formation d'urolithes d'urate et de xanthine tandis que les Deerhounds avaient une association remarquablement élevée avec l'urolithiase de cystine. Il était plus probable que les mâles forment des urolithes d'oxalate de calcium et des urolithes métaboliques et il était plus probable que les femelles développent des urolithes de struvite et mixtes.(Traduit par Isabelle Vallières).

Evaluation of 21 426 feline bladder urolith submissions to the Canadian Veterinary Urolith Centre (1998-2014).

This study reports emerging trends in feline urolithiasis in Canada during the past 16.8 y, evaluates associations of breed and gender with urolith types, and reports on feline submissions from outside of Canada. Struvite and calcium oxalate uroliths comprised > 90% of all uroliths submitted. In cats, oxalate submissions outnumbered struvite submissions from Canada, Hong Kong, Denmark, and the United Arab Emirates, while Australian struvite submissions outnumbered calcium oxalate submissions. In Canada, the majority of urolith submissions were from domestic cats followed by Himalayan, Persian, and Siamese cats. Males were more likely to form calcium oxalate uroliths and females were more likely to develop struvite uroliths. Compared to domestic short-haired cats, Tonkinese, Burmese, Devon rex, Himalayan, Persian, and Siamese cats were significantly associated with calcium oxalate urolith submission. Egyptian mau, Birman, ocicat, and Siamese breeds were over-represented amongst urate submissions.

Évaluation de 21 426 soumissions d'urolithes de vessie au Centre canadien d'urolithes vétérinaires (1998­2014). Cette étude présente un rapport sur les tendances émergentes pour l'urolithiase féline au Canada pendant les 16,8 dernières années, évalue les associations avec la race et le sexe pour les types d'urolithes et établit un rapport sur les soumissions félines provenant de l'extérieur du Canada. Les urolithes de struvite et d'oxalate de calcium représentaient > 90 % de tous les urolithes soumis. Chez les chats, les soumissions d'oxalate étaient supérieures aux soumissions de struvite pour les échantillons provenant du Canada, de Hong Kong, du Danemark et des Émirats arabes unis, tandis que les soumissions de struvite provenant de l'Australie étaient supérieures aux soumissions d'oxalate de calcium. Au Canada, la majorité des soumissions d'urolithes provenaient de chats domestiques suivis des chats himalayens, persans et siamois. Il était plus probable que les mâles aient des urolithes d'oxalate de calcium et il était plus probable que les femelles développent des urolithes de struvite. Comparativement aux chats domestiques à poil court, les chats tonkinois, burmese, Devon rex, himalayens, persans et siamois présentaient une association importante avec une soumission d'urolithes d'oxalate de calcium. Les races de chat Mau égyptien, birman, ocicat et siamois étaient surreprésentées parmi les soumissions d'urate.(Traduit par Isabelle Vallières).

2,8-Dihydroxyadenine uroliths in a dog.

CASE DESCRIPTION: A 43-kg (95-lb) 4-year-old neutered male mixed-breed dog was evaluated because of a 2-day history of dysuria. CLINICAL FINDINGS: Radiography and ultrasonography revealed hydronephrosis, hydroureter, and radiolucent, hyperechoic uroliths in the right kidney and ureter and the urinary bladder. Serum bile acids concentration was within the reference interval. TREATMENT AND OUTCOME: The uroliths in the bladder and right ureter were surgically removed and submitted for analysis. They were initially identified as urate uroliths; however, results of further analysis indicated uroliths were composed of 2,8-dihydroxyadenine (2,8-DHA), and 2,8-DHA was identified in a urine sample of the dog. Allopurinol was prescribed for the dog, and a purine-restricted diet was recommended. CLINICAL RELEVANCE: 2,8-DHA uroliths are extremely rare in humans and dogs. Such uroliths may be underdiagnosed in humans because of variability of clinical signs and difficulty in differentiating 2,8-DHA and urate uroliths and crystalluria. Uroliths composed of 2,8-DHA may be misdiagnosed as urate uroliths in dogs.

A diet with a struvite relative supersaturation less than 1 is effective in dissolving struvite stones in vivo.

Magnesium ammonium phosphate (struvite) is one of the most common minerals found in feline uroliths. Previous studies have shown the efficacy of acidifying calculolytic diets (inducing urine pH < 6.5), in dissolving struvite stones in cats. Recent work in our laboratory found that wet and dry test diets induce a struvite urinary relative supersaturation (RSS) < 1 and that the urine of healthy cats fed the dry test diet dissolved feline struvite stones in vitro. The objective of the present study was to demonstrate the efficacy of those test diets on naturally occurring struvite urocystoliths in cats. A total of twenty-one cats were used, of which seventeen completed the study. Of the seventeen cats, eight were fed the wet test diet and nine the dry test diet. Uroliths dissolved in a median of 18 (10-55) d. In the remaining four cats, uroliths failed to dissolve and were removed surgically. Quantitative analysis showed that these uroliths contained either calcium oxalate or calcium phosphate. The present study demonstrates that diets that induce a struvite RSS < 1 result in struvite stone dissolution in vivo.

Uncontrolled study assessing the impact of a psyllium-enriched extruded dry diet on faecal consistency in cats with constipation.

Two field trials, involving 66 cats (15 trial 1; 51 trial 2) were conducted to assess the efficacy of a psyllium-enriched diet for management of constipation in cats. After investigations and faecal evacuation (by enema if required), all cats were fed on a moderate fibre, psyllium-enriched, dry extruded diet. Additional therapy was either not used (trial 1), or initially allowed but was subsequently withdrawn if possible (trial 2). The diet was well tolerated, and palatability was excellent. Most cases improved after initial therapy (at 2 months; trial 1: 14/15 [93%]; trial 2: 42/51 [82%]), and faecal consistency improved significantly in both trials (P < 0.001). Use of cisapride and lactulose decreased significantly in trial 2 (P < 0.001 for both). The diets used in these pilot studies were efficient in the management of recurrent feline constipation. Randomised control trials are now recommended to examine whether a clinical benefit can be proven.

Ova of Dioctophyme renale in a canine struvite urolith.

This report describes light and scanning electron microscopic appearance of an ovum from the giant kidney worm, Dioctophyme renale found in the nidus and stone layer of a struvite calculus. The stone had been surgically removed from the bladder of a 4-year-old spayed female mixed breed dog from northern Ontario.

Risk factors for the incidence of calcium oxalate uroliths or magnesium ammonium phosphate uroliths for dogs in Ontario, Canada, from 1998 to 2006.

OBJECTIVE: To investigate individual- and community-level contextual variables as risk factors for submission of calcium oxalate (CaOx) uroliths or magnesium ammonium phosphate (ie, struvite) uroliths for dogs to a national urolith center, as determined on the basis of urolith submission patterns. SAMPLE POPULATION: Records of 7,297 dogs from Ontario, Canada, with CaOx or struvite uroliths submitted to the Canadian Veterinary Urolith Centre from 1998 through 2006. PROCEDURES: Data were analyzed via multilevel multivariable logistic regression. RESULTS: Individual-level main effects and interactions significantly associated with the risk of submission of CaOx uroliths rather than struvite uroliths included age, sex, breed group, neuter status, body condition, dietary moisture content, diet type, sex-neuter status interaction, sex-age interaction, body condition-age interaction, and breed group-dietary moisture content interaction. In addition, median community family income and being located within a major urban center (ie, Toronto) were significant risk factors for submission of CaOx uroliths, compared with submission of struvite uroliths. CONCLUSIONS AND CLINICAL RELEVANCE: Individual-level and dietary factors for dogs affected the risk of submission of CaOx uroliths, relative to that of struvite uroliths. Interactions among these variables need to be considered when assessing the impact of these risk factors. In addition, community-level or contextual factors (such as community family income and residing in a densely populated area of Ontario) also affected submission patterns, although most of the variance in the risk for submission of CaOx uroliths, compared with the risk for submission of struvite uroliths, was explained by individual-level factors.

Feline urate urolithiasis.

This retrospective case control study describes associations between feline urate urolithiasis and breed, age, gender, and urine composition. Data from cases of feline uroliths submitted to the Canadian Veterinary Urolith Centre (CVUC) between February 2, 1998 and July 7, 2007 were reviewed. There were 10 083 feline uroliths examined, including 385 ammonium urate, 13 uric acid, and 21 mixed struvite/urate uroliths. The Egyptian Mau, Birman, and Siamese breeds were significantly predisposed to urate urolithiasis [odds ratio (OR) = 118, 95% confidence interval (CI) = 38.2 to 510, P < 0.001], (OR = 9.1, 95% CI = 2.0 to 32, P < 0.001) and (OR = 3.9, 95% CI = 2.5 to 5.9, P < 0.001), respectively. Urate urolithiasis was more frequent in younger cats (mean age 6.3 versus 7.1 y in cats with other uroliths, P < 0.0001) and in male cats (P = 0.024). The association between Egyptian Maus and urate urolithiasis was remarkable. The association in Siamese cats is consistent with prior reports, and the association with Birman cats requires further study.

Canine and feline urolithiasis: examination of over 50 000 urolith submissions to the Canadian veterinary urolith centre from 1998 to 2008.

This study reports on trends in canine and feline urolithiasis in Canada during the past 10 years. Age, sex, breed of animals and mineral composition from 40 637 canine and 11 353 feline bladder uroliths submitted to the Canadian Veterinary Urolith Centre between 1998 and 2008 were recorded. Struvite and calcium oxalate uroliths comprised > 85% of all uroliths submitted. In dogs, the number of struvite submissions has declined and the number of calcium oxalate submissions has increased. Struvite uroliths were most common in female dogs and calcium oxalate uroliths in male dogs. The shih tzu, miniature schnauzer, bichon frisé, lhasa apso, and Yorkshire terrier were the breeds most commonly affected for both struvite and calcium oxalate uroliths. Urate uroliths were most common in male dalmatians. In cats, struvite submissions declined and calcium oxalate submissions remained constant. Struvite and calcium oxalate uroliths were common in domestic, Himalayan, Persian, and Siamese cats. Urate uroliths were over-represented in Egyptian maus.

Evaluation of risk factors associated with suture-nidus cystoliths in dogs and cats: 176 cases (1999-2006).

OBJECTIVE: To characterize and evaluate risk factors for suture-associated cystoliths in dogs and cats. DESIGN: Retrospective case-control study. Animals-163 dogs and 13 cats with suture-associated cystoliths and 326 control dogs and 26 control cats with non-suture-associated cystoliths. PROCEDURES: Submissions to the Canadian Veterinary Urolith Centre received from 1999 to 2006 were reviewed. Case dogs and cats had cystoliths associated with visible suture or with hollow, cylindrical channels or suture knot impressions consistent with dissolved suture. Control dogs and cats had at least a single recurrent non-suture-associated cystolith submitted closest in time to the sample case. Associations among cystolith composition, recurrence times, sex, age, and breed were evaluated. RESULTS: Cases consisted of 92 dogs and 7 cats with visible suture and 71 dogs and 6 cats with dissolved suture. Suture-associated cystoliths represented 0.6% of canine cystoliths, 9.4% of recurrent canine cystoliths, 0.17% of feline cystoliths, and 4% of recurrent feline cystoliths. Sexually intact and neutered males were at increased odds of suture-associated cystoliths, relative to spayed female dogs. Shih Tzus, Lhasa Apsos, and Pomeranians were significantly predisposed to form suture-associated cystoliths. In dogs, compound suture-associated cystoliths were significantly more likely than other cystolith types (OR, 8.6). Dogs with suture-associated cystoliths had significantly shorter recurrence times than did control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Suture remnants in the bladder have an important role in recurrent cystolithiasis in dogs. Identification of risk factors is important for avoiding recurrence of iatrogenic cystoliths.

Evaluation of the efficacy of a commercial diet in the dissolution of feline struvite bladder uroliths.

Clinical signs of struvite urolithiasis resolved in an average of 19 days in cats fed either a canned or dry urine-acidifying, magnesium-restricted diet, and stones completely dissolved in 31 of 39 cats in an average of 30 days. Stones were surgically removed from five cats, and analysis revealed that these stones were not composed of struvite. The results of this study strongly suggest that the diet will dissolve naturally occurring feline struvite bladder uroliths.

Dissolution of infection-induced struvite bladder stones by using a noncalculolytic diet and antibiotic therapy.

An 8-year-old, female spayed miniature schnauzer was presented for pollakiuria and gross hematuria. Infection-induced struvite urolithiasis with concurrent bacterial urinary tract infection was diagnosed. The treatment is described, followed by a brief discussion of struvite stones and their medical management.

Canine urolithiasis: a look at over 16 000 urolith submissions to the Canadian Veterinary Urolith Centre from February 1998 to April 2003.

The purpose of this study was to report on the age, sex, breed, and mineral composition of 16 647 canine bladder uroliths submitted to the Canadian Veterinary Urolith Centre between February 1998 and April 2003. Each urolith submission was accompanied by a questionnaire. Of the submissions, approximately 43.8% were struvite and 41.5% oxalate. Struvite uroliths were most common in female dogs. Mixed breed dogs predominated, followed by the shih tzu, bichon frise, miniature schnauzer, Lhasa apso, and Yorkshire terrier. Oxalate uroliths were most common in males and in the miniature schnauzer, bichon frise, Lhasa apso, shih tzu, and Yorkshire terrier. Urate uroliths were most common in male Dalmations. Other urolith types, including cystine, xanthine, silica, and calcium phosphate, were less commonly reported. A review of risk factors for the various uroliths is presented, along with some recommendations for treatment and prevention.

Feline urethral plugs and bladder uroliths: a review of 5484 submissions 1998-2003.

The results of 5484 submissions from cats to the Canadian Veterinary Urolith Centre between February 1998 and February 2003 are presented. Of the submissions, 618 were urethral plugs and 4866 were bladder uroliths. The majority of the urethral plugs were from male domestic shorthair and longhair cats. Approximately 50% of the urolith submissions were oxalate, 44% were struvite. Oxalate uroliths were the most common mineral type in males and in Himalayan, Persian, and Siamese cats. Struvite uroliths were the most common mineral type in domestic shorthair and longhair cats. Females outnumbered males by 1.4:1 in struvite urolith submissions. A review of risk factors for urethral plugs and bladder uroliths is presented.