struvite and Cat-Diseases

Urolithiasis is a general term referring to the causes and effects of stones anywhere in the urinary tract. Urolithiasis should not be viewed conceptually as a single disease with a single cause, but rather as a sequela of multiple interacting underlying abnormalities. Thus, the syndrome of urolithiasis may be defined as the occurrence of familial, congenital, or acquired pathophysiologic factors that, in combination, progressively increase the risk of precipitation of excretory metabolites in urine to form stones (ie, uroliths). The following epidemiologic discussion is based on quantitative analysis of 350,803 canine uroliths, 94,778 feline uroliths, and 6310 feline urethral plugs submitted to the Minnesota Urolith Center from 1981 to 2007.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Breeding; Calcium Oxalate; Cat Diseases; Cats; Dog Diseases; Dogs; Female; Magnesium Compounds; Male; Minnesota; Phosphates; Risk Factors; Struvite; Urinary Calculi; Urolithiasis

Feline urolithiasis represents 15% of all cases of nonobstructive lower urinary tract disease in cats. Approximately 50% of feline uroliths are composed of struvite. Struvite urolithiasis commonly recurs, but optimal management may decrease its frequency. The pathophysiology and management of struvite urolithiasis are different in cats and dogs. This article focuses on struvite urolithiasis in cats, highlighting important aspects of pathophysiology, treatment, and prevention.

Topics: Age Factors; Animals; Breeding; Cat Diseases; Cats; Female; Hydrogen-Ion Concentration; Magnesium Compounds; Male; Phosphates; Risk Factors; Species Specificity; Struvite; Urolithiasis

Diagnostic imaging is usually required to determine the presence of urolithiasis. Double-contrast cystography is more accurate than survey radiography and approximately as accurate as ultrasonography. Knowledge of the mineral composition of calculi helps direct appropriate management of urolithiasis, and signalment can help predict composition with about 70% accuracy. In cats, about half of cystic calculi are struvite and half are calcium oxalate; most nephroliths and ureteroliths are calcium oxalate. In female dogs, struvite uroliths are the predominant type found in the bladder. In male dogs, breed plays a strong role in prediction of bladder urolith type. It is difficult to predict the composition of nephroliths and ureteroliths based on signalment alone in dogs. Urinalysis and imaging findings can help in predicting urolith composition, although chemical analysis is necessary for definitive diagnosis.

Topics: Animals; Calcium Oxalate; Cat Diseases; Cats; Diagnosis, Differential; Dog Diseases; Dogs; Female; Magnesium Compounds; Male; Pedigree; Phosphates; Radiography, Abdominal; Sex Factors; Struvite; Ultrasonography; Ureteral Calculi; Uric Acid; Urolithiasis

A variety of different types of uroliths occur in cats, of which calcium oxalate and magnesium ammonium phosphate are the most common. Treatment and prevention are most likely to be successful if associated risk factors are identified and eliminated or controlled.

Topics: Animals; Calcium Oxalate; Calcium Phosphates; Cat Diseases; Cats; Cystine; Magnesium Compounds; Phosphates; Risk Factors; Struvite; Uric Acid; Urinary Calculi

Feline urethral plugs commonly are composed of large quantities of matrix mixed with minerals (especially struvite). However, some urethral plugs are composed primarily of matrix, some consist of sloughed tissue, blood, and/or inflammatory reactants, and a few are composed primarily of aggregates of crystalline minerals. The formation of matrix-crystalline urethral plugs may be analogous to the preparation of fruit jello.

Topics: Animals; Calcium Oxalate; Calcium Phosphates; Cat Diseases; Cats; Magnesium Compounds; Male; Minerals; Phosphates; Purines; Struvite; Urethral Obstruction; Urinary Calculi

Companion animal diets may be related to prevention, pathogenesis and/or treatment of diseases of the lower urinary tract. For example, urolithiasis can be either diet induced or nutrient sensitive. One of the most interesting developments in veterinary urolithiasis research has been the recent change in the composition of stones recovered from cats. In 1984, 88% of stones analyzed by quantitative methods were > 70% struvite, whereas < 1% were calcium oxalate. In 1992, the percentage of struvite had dropped to 62, whereas the percentage of calcium oxalate had increased to 24. Another recent development in lower urinary tract disease of cats is the recognition that urolithiasis appears to be a minor cause of the signs of frequency, urgency and hematuria for which patients are presented. This suggests that diet may no longer be involved, or be involved in previously unrecognized ways, in many current cases of this disease. Some of these feline patients may have a disease similar to interstitial cystitis, a disease of humans that appears to be of neuroepithelial origin. Our laboratory has been studying this possibility recently, and many similarities between the two diseases have been found.

Topics: Animal Feed; Animals; Calcium Oxalate; Cat Diseases; Cats; Cystitis; Female; Humans; Magnesium Compounds; Male; Phosphates; Struvite; Urinary Calculi; Urologic Diseases

Topics: Animals; Cat Diseases; Cats; Dog Diseases; Dogs; Humans; Magnesium; Magnesium Compounds; Phosphates; Radiography; Struvite; Ureaplasma; Urinary Calculi; Urinary Tract Infections

A diet providing less than 20 mg of magnesium per 100 kcal that maintains urine pH near 6.0 3 to 5 hours after eating, or a diet providing this amount fo magnesium (see Table 2) with 1 gm of ammonium chloride or 1.5 gm of dl-methionine added daily, should be fed for 1 to 3 months to dissolve struvite uroliths (see Fig. 1). The low-magnesium diet should be fed indefinitely to prevent recurrence, because struvite urolithiasis and all of its effects (hematuria, pollakiuria, and/or complete to partial obstruction to urinary excretion) recurs repeatedly in cats that have previously experienced the condition if they are returned to regular cat food. In contrast, if a diet low in magnesium is fed, recurrence is uncommon. For cats that have never been affected, feeding a low-magnesium ration is unnecessary. For all cats, the following measures are recommended: encourage exercise, allow frequent urination, prevent obesity, decrease confinement, keep the litter box clean, and always have palatable water readily available.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Magnesium; Magnesium Compounds; Methionine; Phosphates; Sodium Chloride; Struvite; Urinary Calculi

This case is typical of recurrent urolithiasis managed by repeated surgery. Retrospective assessment of the disorder indicates the need for quantitative analyses of uroliths removed by cystotomy. Compliance of the owners with recommendations to minimize recurrent urolithiasis might have been beneficial. Results of medical therapy designed to induce dissolution of uroliths in this case are representative of preliminary findings of medical dissolution of naturally occurring struvite uroliths in ten other cats. It is of interest that the uroliths dissolved even though no effort was made to induce diuresis. The underlying cause of UTI in this patient may have been damage to the lower urinary tract induced by previous diagnostic and therapeutic procedures and/or sterile struvite uroliths that compromised local host defense mechanisms. Lack of urease production by the uropathogens suggests that they did not play a causative role in formation of uroliths. The need for preventative therapy of recurrent formation of uroliths after their medical dissolution is worthy of further comment. In this patient, specific measures to prevent urolith recurrence were not initiated because it is a part of a prospective clinical study. In the event uroliths recur, medical therapy designed to induce dissolution of uroliths would be repeated. Need for long-term preventative therapy would be dependent on the time interval between recurrent episodes (weeks, months, or years), and the effectiveness of medical therapy for urolith dissolution. Long-term prophylactic therapy would include urine acidifiers and diets low in magnesium.

Topics: Ammonium Chloride; Animals; Anti-Infective Agents; Anti-Inflammatory Agents; Cat Diseases; Cats; Diverticulum; Female; Magnesium; Magnesium Compounds; Male; Methionine; Parasympatholytics; Phosphates; Struvite; Urachus; Urinary Calculi; Urinary Tract Infections

Lower urinary tract disease (LUTD) occurs commonly in cats, and idiopathic cystitis (FIC) and urolithiasis account for >80% of cases in cats <10 years of age. Although several strategies have been recommended, a common recommendation is to induce dilute urine resulting in more frequent urination and to dilute calculogenic constituents. In addition to conventional therapy using modified diets, traditional Chinese and Western herbs have been recommended, although only one - choreito - has published data available. We evaluated three commonly used herbal treatments recommended for use in cats with LUTD: San Ren Tang, Wei Ling Tang and Alisma. We hypothesized that these three Chinese herbal preparations would induce increased urine volume, decreased urine saturation for calcium oxalate and struvite, and differences in mineral and electrolyte excretions in healthy cats.. Six healthy spayed female adult cats were evaluated in a placebo-controlled, randomized, crossover design study. Cats were randomized to one of four treatments, including placebo, San Ren Tang, Wei Ling Tang or Alisma. Treatment was for 2 weeks each with a 1 week washout period between treatments. At the end of each treatment period, a 24 h urine sample was collected using modified litter boxes.. Body weights were not different between treatments. No differences were found in 24 h urinary analyte excretions, urine volume, urine pH or urinary saturation for calcium oxalate or struvite between treatments.. The results of this study do not support the hypothesis; however, evaluation of longer-term and different dosage studies in cats with LUTD is warranted.

Topics: Animals; Calcium Oxalate; Cat Diseases; Cats; Drugs, Chinese Herbal; Female; Hematuria; Magnesium Compounds; Male; Pilot Projects; Struvite; Urolithiasis; Urologic Diseases

To evaluate the influence of two feline calculolytic diets on selected parameters of mineral metabolism.. Two dry commercial diets designed for struvite urolith dissolution were evaluated in 14 cats. The study was designed as a two-sequence, four-period crossover protocol with a baseline period, two 60-day "run-in" periods in which calculolytic diets (Diet 1 and Diet 2) were fed and one 30-day "wash-out" period. Data are expressed as median (range).. Feeding the calculolytic diets for two months did not alter plasma concentrations of calcium, phosphorus, magnesium and parathyroid hormone. A significant (P < 0.05 in each case) decline in calcitriol was observed after administering both diets from 236.4 (122.4-429.6) to 170.4 (108.0-394.3) pmol/L (Diet 1) and from 278.4 (153.6-492.0) to 177.1 (87.6-392.4) pmol/L (Diet 2). Cats fed Diet 1 showed a significant increase in urine calcium concentration (from 0.3 (0.2-0.5) to 0.4 (0.3-0.7) mmol/L). Magnesium concentration in urine was significantly increased with both diets, from 1.4 (0.1-1.7) to 1.5 (1.3-2.4) mmol/L (Diet 1) and from 1.1 (0.4-1.9) to 2.0 (0.1-3.1) mmol/L (Diet 2).. Both diets resulted in an increased urinary concentration of magnesium, through different mechanisms: urine acidification (Diet 1) and increased sodium load (Diet 2).

Topics: Animals; Calcium; Cat Diseases; Cats; Diet; Female; Magnesium; Magnesium Compounds; Male; Phosphates; Struvite; Treatment Outcome; Urinary Bladder Calculi

To compare the efficacy and safety of using 2 commercially available, low-magnesium, urine-acidifying dry foods to dissolve sterile struvite uroliths in cats.. Prospective, multicenter, randomized clinical trial .. 37 cats with presumed struvite uroliths.. 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.. 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.. 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.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Diet; Female; Magnesium Compounds; Male; Phosphates; Struvite; Urolithiasis

It has been reported that daily fluid intake influences urinary dilution, and consequently the risk of urolithiasis in human subjects and dogs. The aim of the present study was to investigate the role of dietary moisture on urinary parameters in healthy adult cats by comparing nutritionally standardised diets, varying only in moisture content. A total of six cats were fed a complete dry food (6.3 % moisture) hydrated to 25.4, 53.2 and 73.3 % moisture for 3 weeks in a randomised block cross-over design. Urinary specific gravity (SG), urine volume, water drunk and total fluid intake were measured daily; relative supersaturation (RSS) for calcium oxalate (CaOx) and struvite was calculated using the SUPERSAT computer program. Cats fed the 73.3 % moisture diet produced urine with a significantly lower SG (P < 0.001) compared with diets containing 53.2 % moisture or lower. Mean RSS for CaOx was approaching the undersaturated zone (1.14 (sem 0.21); P = 0.001) for cats fed the diet with 73.3 % moisture and significantly lower than the 6.3 % moisture diet (CaOx RSS 2.29 (sem 0.21)). The effect of diet on struvite RSS was less clear, with no significant difference between treatment groups. Total fluid intake was significantly increased (P < 0.001) in the 73.3 % moisture diet (144.7 (SEM 5.2) ml, or 30 ml/kg body weight per d) compared with the 6.3 % (103.4 (SEM 5.3) ml), 25.4 % (98.6 (SEM 5.3) ml) and 53.3 % (104.7 (SEM 5.3) ml) moisture diets, despite voluntary water intake decreasing as dietary moisture intake increased. Cats fed the 73.3 % moisture diet had a higher total daily fluid intake resulting in a more dilute urine with a lower risk of CaOx when compared with the lower-moisture diets.

Topics: Animal Feed; Animals; Calcium Oxalate; Cat Diseases; Cats; Cross-Over Studies; Diet; Drinking; Female; Magnesium Compounds; Male; Phosphates; Struvite; Water

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.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Diet; Female; Magnesium Compounds; Male; Phosphates; Struvite; Urinary Bladder Calculi

Prednisolone (10 mg PO q24h) or placebo was administered to healthy cats for 2 weeks in a masked, placebo-controlled, crossover-design study, and 24-hour urine samples were collected. When cats received prednisolone, 24-hour urine pH was lower and 24-hour urine excretion of creatinine, magnesium, phosphate, and potassium was higher than when cats received placebo. No significant difference was found in urinary relative supersaturation for calcium oxalate (CaOx) or struvite between treatment groups. Prednisolone administration did not induce diuresis, nor was it associated with increased calcium excretion or urinary saturation for CaOx in these healthy cats. Results of this study, however, should not be extrapolated to cats that form CaOx uroliths associated with idiopathic hypercalcemia.

Topics: Administration, Oral; Animals; Anti-Inflammatory Agents; Calcium Oxalate; Cat Diseases; Cats; Cross-Over Studies; Female; Magnesium Compounds; Phosphates; Prednisolone; Struvite; Treatment Outcome; Urinalysis; Urinary Calculi

Hydrochlorothiazide (1 mg/kg PO q12h) or placebo was administered to healthy cats for 2 weeks in a masked, placebo-controlled, crossover-design study, and 24-hour urine samples were collected. When cats received hydrochlorothiazide, 24-hour urine volume, ammonia, chloride, creatinine, magnesium, oxalic acid, phosphate, potassium, and sodium were significantly higher than when cats received placebo. Hydrochlorothiazide was associated with significantly lower urinary saturation for calcium oxalate, but no difference was found in 24-hour urine calcium and citrate, urinary saturation for struvite, or blood ionized calcium. Hydrochlorothiazide decreased urinary saturation for calcium oxalate and could be useful in managing cats with calcium oxalate uroliths. Results of this study, however, should not be extrapolated to cats that form calcium oxalate uroliths.

Topics: Administration, Oral; Animals; Calcium Oxalate; Cat Diseases; Cats; Cross-Over Studies; Female; Hydrochlorothiazide; Magnesium Compounds; Phosphates; Sodium Chloride Symporter Inhibitors; Struvite; Treatment Outcome; Urinalysis; Urinary Calculi

To evaluate the effects of a high-protein diet versus dietary supplementation with ammonium chloride (NH4Cl) on struvite crystal formation in the urine of clinically normal cats by measuring the urine concentration of hydrochloric acid (HCl)-insoluble sediment, urine pH, struvite activity product (SAP), number of struvite crystals in urine, and urine volume.. 23 healthy adult cats.. Urine was fractionated by centrifugation with subsequent extraction of the sediment with 1 N HCl (study 1). Diets containing either 29% crude protein or 55% crude protein were fed to cats in a crossover trial of 3 weeks/period (study 2). Diets supplemented with either sodium chloride (NaCl) or NH4Cl were fed, by use of a 3 x 3 Latin-square design with 3 wk/period (study 3). In studies 2 and 3, urine samples were collected for the last 7 days of each period.. The HCl-insoluble sediment contained Tamm-Horsfall glycoprotein (THP; study 1). The high-protein diet (study 2) and dietary supplementation with NH4Cl (study 3) resulted in a decrease in urine pH, SAP, and the number of struvite crystals in urine. However, the high-protein diet decreased urine concentrations of HCl-insoluble sediment containing THP (study 2), in contrast to the NH4Cl supplementation that increased urine volume without a significant effect on the urine concentration of the HCl-insoluble sediment (study 3).. Our results indicate that compared with dietary supplementation with NH4Cl, the high-protein diet is preferable as a urine acidifier for the prevention of struvite crystal formation in clinically normal cats.

Topics: Ammonium Chloride; Animal Feed; Animals; Cat Diseases; Cats; Cross-Over Studies; Dietary Proteins; Dietary Supplements; Female; Hydrogen-Ion Concentration; Magnesium Compounds; Male; Phosphates; Struvite; Urinary Calculi

This study was aimed to assess the distribution and frequency of uroliths in cats as well as to evaluate gender-, age-, and breed-specific differences.. 3629 uroliths from cats in Germany were analyzed by infrared-spectroscopy during the period 2016-2020. The majority (3300) of the uroliths originated from purebred cats of 22 breeds.. Uroliths were prevalent in the order of male neutered (45.3 %), female spayed (35.3 %), male intact (7.4 %), and female intact cats (6.3 %). Median age of the cats with uroliths was 7 years, although it varied slightly depending on types of the urolith. The most frequent uroliths were calcium oxalate (59.5 %), followed by struvite (33.7 %), ammonium urate (2 %), calcium phosphate (1.7 %), cystine (0.7 %) and xanthine (0.4 %). Males (59.4 %) and females (59.2 %) showed nearly identical prevalence of calcium oxalates, whereas it significantly diverged in castrated (60.2 %) versus intact animals (54.4 %; p = 0.01). With regard to struvites, male cats (32.6 %) were less prone than females (35.4 %; p = 0.08) while intact cats (38.2 %) significantly outnumbered the castrated cohorts (33.1 %; p = 0.02). The prevalence for calcium oxalate uroliths increased by 6.6 % during the study period, contrasting a decrease of 5.5 % for struvites. Some breeds (> 10 individuals) showed significantly higher propensities than others for urolith formation. Calcium oxalates were significantly more frequent in British shorthair cats (85.2 %), Ragdoll (75 %), Scottish fold (74.1 %) and Persians (72.4 %). Struvites were prevailing in Norwegian forest cats (48.5 %), British longhair (41.7 %), European shorthair (41.7 %) and Siberian forest cats (36.8 %). Siamese cats had the significantly highest percentage of cystine uroliths (16 %).. The occurrence of urine calculi in cats from Germany was found to be most frequent for calcium oxalate and struvite types. We also found breed-, age-, gender- specific differences in addition to variations depending on the neutering status of the animals.. Ziel der Studie war, die Verteilung und Häufigkeit unterschiedlicher Harnsteine von Katzen aus Deutschland zu erfassen sowie geschlechts-, alters-, und rassespezifische Unterschiede zu evaluieren.. Im Zeitraum 2016–2020 wurden mittels Infrarotspektroskopie 3629 Harnsteinproben von Katzen aus Deutschland analysiert. 3330 Harnsteine stammten von Rassekatzen, die 22 Rassen zugeordnet werden konnten.. Die Harnsteine entfielen auf männlich kastrierte (45,3 %), weiblich kastrierte (35,3 %), männlich intakte (7,4 %) und weiblich intakte (6,3 %) Tiere. Das mediane Alter (Jahre) der Tiere war 7, variierte aber zwischen den unterschiedlichen Steinarten. Die häufigsten Steinarten waren: Kalziumoxalate (59,5 %), Struvite (33,7 %), Ammoniumurate (2 %), Kalziumphosphate (1,7 %), Cystine (0,7 %) und Xanthine (0,4 %). Männliche (59,4 %) und weibliche (59,2 %) Tiere hatten nahezu identische prozentuale Anteile an Kalziumoxalaten, während der Anteil bei Kastraten mit 60,2 % signifikant höher war als bei intakten Tieren (54,4 %; p = 0,01). Bei Struvitsteinen war der Anteil männlicher (32,6 %) geringer als der weiblicher Tiere (35,4 %; p = 0,08) und der Anteil der intakten Tiere (38,2 %) übertraf den der kastrierten Tiere signifikant (33,1 %; p = 0,02). Die Prävalenz der Kalziumoxalatsteine stieg im Untersuchungszeitraum um 6,6 %, während die der Struvitsteine 5,5 % abnahm. Einige Rassen (> 10 Individuen) zeigten eine signifikant gehäufte Neigung zur Bildung bestimmter Steinarten. Kalziumoxalate fanden sich signifikant häufiger bei Britisch Kurzhaar (85,2 %), Ragdoll (75 %), Scottish Fold (74,1 %) und Perserkatzen (72,4 %). Struvitsteine waren die dominierende Steinart bei Norwegischer Waldkatze (48,5 %), Britisch Langhaar (41,7 %), Europäisch Kurzhaar (41,7 %) und Sibirischer Waldkatze (36,8 %). Siamkatzen hatten den signifikant höchsten prozentualen Anteil an Cystinsteinen (16 %) SCHLUSSFOLGERUNG UND KLINISCHE RELEVANZ: Kalziumoxalate und Struvitsteine sind bei Katzen aus Deutschland die häufigsten Steinarten. Rasse-, alters-, geschlechts- und kastrationsspezifische Unterschiede wurden festgestellt.

Topics: Age Factors; Animals; Calcium; Calcium Oxalate; Cat Diseases; Cats; Cystine; Female; Germany; Magnesium Compounds; Male; Phosphates; Struvite; Urinary Calculi

Persistent uroliths after a cystotomy in dogs are a common cause of surgical failure.. This study examined the following: the success rate of retrograde urohydropropulsion in male dogs using non-enhanced computed tomography (CT), whether the CT mean beam attenuation values in Hounsfield Units (mHU) measured. All dogs and cats that presented with lower urinary tract uroliths and had a non-enhanced CT preceding surgery were included. In male dogs, CT was performed after retrograde urohydropropulsion to detect the remaining urethral calculi. The percentage and location of persistent calculi were recorded. The images were reconstructed using three kernels, from smooth to ultrasharp, and the calculi mHU were measured.. Sixty-five patients were included in the study. The success rate of retrograde urohydropropulsion in the 45 male dogs was 55.6% and 86.7% at the first and second attempts, respectively. The predominant components of the calculi were cystine (20), struvite (15), calcium oxalate (8), and urate (7). The convolution kernel influenced the mHU values (p < 0.05). The difference in mHU regarding the calculus composition was better assessed using the smoother kernel. A mHU greater than 1,000 HU was predictive of calcium oxalate calculi.. Non-enhanced CT is useful for controlling the success of retrograde urohydropropulsion. The mHU could allow a prediction of the calculus composition, particularly for calcium oxalate, which may help determine the therapeutic strategy.

Topics: Animals; Calcium Oxalate; Calculi; Cat Diseases; Cats; Cystine; Dog Diseases; Dogs; Male; Struvite; Tomography, X-Ray Computed; Uric Acid; Urinary Calculi

The aim of the study was to determine the efficacy of the low struvite relative supersaturation diet in dissolution of feline struvite cystoliths.. This was a prospective, open-label, two-center study. Twelve client-owned cats were enrolled based on the radiographic appearance of their uroliths and urinalysis parameters. Cats were fed the test diet exclusively for up to 56 days. Cats were radiographed every other week until radiographic evidence of dissolution occurred or the end of the study period was reached. Cats with radiographically apparent uroliths at the end of the study period underwent cystotomy for stone retrieval and analysis.. Nine of the 12 cats completed the study. Eight experienced radiographic dissolution; seven of these had complete dissolution within the first month of treatment. One cat, whose owner declined cystotomy after partial dissolution at day 56, had complete radiographic resolution at 70 days of treatment. Two calcium oxalate urolith cores were removed from a cat that had partial radiographic dissolution.. The test diet was successful in dissolving suspected struvite cystoliths. As this diet is suitable for maintenance feeding of adult cats, it may be a suitable choice for long-term prevention of feline struvite urolithiasis.

Topics: Animals; Cat Diseases; Cats; Diet; Magnesium Compounds; Phosphates; Prospective Studies; Solubility; Struvite; Urinary Bladder Calculi; Urolithiasis

There is an apparent reciprocal relationship between magnesium ammonium phosphate (MAP, struvite) and calcium oxalate (CaOx) urolithiasis incidence rate in cats. The number of struvite uroliths submitted for analysis over the past 35 years has been decreasing, with an increase in CaOx urolith submissions. Commercial diets aimed to dissolve struvite uroliths are typically acidified, and it has been suggested that dietary acidification increases urinary calcium excretion and the risk of CaOx crystallization. The objective of this study was to assess the effect of urine acidification on the relative supersaturation (RSS) of CaOx in cats, as a representation of crystallization risk. Four diets were extruded to contain identical nutrient contents, but with gradual acidification (0, 0.6, 1.3 and 1.9% sodium bisulphate substituted sodium chloride in diets A, B, C and D respectively). Thirteen adult cats were fed each diet sequentially for a minimum of 10 days. Average urine pH was 6.4, 6.2, 6.0 and 5.9 on diets A, B, C and D respectively (p < 0.0001). Struvite RSS decreased on diets inducing more acidic urine pH (p < 0.0001). Urinary calcium excretion and concentration increased with diets inducing lower urine pH (p < 0.0001), but oxalate excretion and concentration decreased (p < 0.001). CaOx RSS was not different between diets (p = 0.63). These results suggest that a lower diet base excess and resulting urine pH to support struvite dissolution do not increase the risk for CaOx crystallization in the range of urine pH representative of most commercial feline diets. Long-term studies are needed to confirm this.

Topics: Animals; Calcium; Calcium Oxalate; Cat Diseases; Cats; Diet; Hydrogen-Ion Concentration; Struvite; Urinary Calculi

Analysis of large datasets of uroliths is necessary to illustrate the prevalence and risk factors of urolithiasis. Furthermore, it may help to improve treatment and prevention of urolithiasis. In this study, 7866 uroliths (44.5% feline and 55.5% canine) from veterinary practitioners in the Netherlands between 2014 and 2020 were analysed. Between 2014 and 2020 the distribution over the different types of uroliths remained similar over time. Female cats, obese cats, Domestic Shorthair cats, female dogs, and large breed dogs had an increased risk for struvite. Neutered cats, all cat breeds except Domestic Shorthair, neutered dogs, male dogs, intact male dogs, and small breed dogs had an increased risk for calcium oxalate urolithiasis. Cystine and urate were found predominantly in male dogs. Dalmatians were at highest risk for urate urolithiasis. The findings of this study in the Netherlands were similar to findings in previous studies from different countries. However, urate urolithiasis in the English Cocker Spaniel and cystine urolithiasis in the Yorkshire Terrier were new associations. Body condition score, information about recurrence of urolithiasis, medical history, and diet history should be included in submission sheets in the future to explore other possible associations.

Topics: Animals; Calcium Oxalate; Cat Diseases; Cats; Dog Diseases; Dogs; Female; Magnesium Compounds; Male; Netherlands; Phosphates; Risk Factors; Struvite; Uric Acid; Urinary Calculi; Urolithiasis

The aim of the study was to identify any dietary, signalment, geographic and clinical factors associated with hematuric struvite crystalluria (HSC) in a population of cats that visit general care veterinary hospitals in the USA.. In total, 4032 cats that had a first-time diagnosis of HSC and 8064 control cats with no history of hematuria or crystalluria were identified from medical records of all cats examined between 2007 and 2011 at 790 US veterinary hospitals. Extracted variables included age, sex, neuter status, breed, diet, urinalysis results and history of cystitis. Potential associations between these variables and HSC were estimated.. Controlling for other factors, young cats fed a dry diet had an increased likelihood of HSC relative to young cats fed a non-dry diet. However, as age increased, the likelihood of HSC declined for cats fed a dry diet and increased for cats fed a non-dry diet. Moreover, the odds of HSC were significantly greater when cats were unneutered (vs neutered; odds ratio [OR] 45.52) or had a thin (vs heavy) body condition (OR 23.81), diagnosis of cystitis (OR 2.84), urine protein concentration >30 mg/dl (OR 4.72), alkaline (vs neutral) urine pH (OR 3.34), pyuria (OR 23.67) or bacteriuria (OR 2.24).. The present study provides estimates of the strengths of association between HSC and certain signalment and clinical characteristics of cats. This information could help clinicians to perform a more directed screening for struvite crystalluria in certain cat populations. Follow-up studies that build on the findings of this study could explore the clinical importance of HSC in cats.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Cystitis; Diet; Female; Male; Struvite; Urinary Calculi

The objective of this study was to determine the efficacy of feeding the commercially available diet, Purina Pro Plan Veterinary Diets UR Urinary St/Ox, for the dissolution of struvite cystoliths in cats with naturally occurring disease. Twelve cats with clinical signs of lower urinary tract disease and cystoliths confirmed via radiographs were enrolled. The cats were fed the study diet ad libitum and assessed by abdominal radiographs weekly. Cats with cystoliths that resolved based on radiographs and confirmatory ultrasound examination were considered diet successes. Cats with no change in cystolith size after 2-6 weeks underwent cystotomy for stone removal, aerobic culture and antimicrobial susceptibility testing, and analysis. All cats accepted the study diet, and weight loss was not noted over the course of the study. Total cystolith dissolution was achieved by week 2 for 5 cats, which were presumed to have struvite cystoliths. All other cats underwent cystotomy for stone removal after radiographic evidence of cystoliths were still present at 2 weeks (1 cat with severe signs), 4 weeks (5 cats), or 6 weeks (1 cat). The cystoliths that were surgically removed were calcium oxalate (5 cats) and mixed (2 cats) and would not be expected to dissolve with this diet. Follow-up radiographs from 6 cats fed the diet long term (3 presumed struvite and 3 with other cystoliths removed surgically) were collected from 1 to 6 months after beginning the study and showed no evidence of cystolith recurrence. While larger case numbers are needed, these results suggest that feeding Purina Pro Plan Veterinary Diets UR Urinary St/Ox can successfully dissolve cystoliths that are likely struvite and may lessen the risk of recurrence of struvite and calcium oxalate cystoliths.

Topics: Animal Feed; Animals; Calcium Oxalate; Cat Diseases; Cats; Diet; Diet Therapy; Female; Male; Struvite; Treatment Outcome; Urinary Bladder Calculi

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.

Topics: Animals; Calcium Oxalate; Canada; Cat Diseases; Cats; Female; Genetic Predisposition to Disease; Magnesium Compounds; Male; Odds Ratio; Phosphates; Retrospective Studies; Struvite; Urinary Bladder Calculi

In this study data on composition of uroliths collected from cats and epidemiologic data of affected cats in Switzerland from 2002 to 2009 are summarised. Of 884 stones analysed 50% (n=441) were composed of calcium oxalate, 45% (n=398) of struvite, 3% (n=18) of ammonium urate, 1% (n=12) were mixed stones, 1% (n=9) were composed of silica, 3 stones were solidified blood, 2 consisted of cystine and 1of xanthine. 40% of the ureteral stones were composed of struvite. Domestic cats had significantly less calcium oxalate stones compared to British Shorthair or Persian cats. Cats with calcium oxalate stones were older and cats with struvite stones were younger than other affected cats. Female and male cats were equally affected with stones. Compared to studies from other countries, in Switzerland silica stones occurred more often and ureteral stones were more often composed of Struvite. The present study shows that occurrence and prevalence of urinary calculi of cats from Switzerland exhibited only slight differences to studies from other countries.. In dieser Arbeit werden Daten zur Zusammensetzung von Harnsteinen bei Katzen und epidemiologische Daten dieser Katzen in der Schweiz in den Jahren 2002 bis 2009 zusammengefasst. Von allen 884 analysierten Steinen bestanden 50% (n=441) aus Kalziumoxalat, 45% (n=398) aus Struvit, 3% (n=18) aus Ammoniumurat, 1% (n=12) waren gemischte Steine, 1% (n=9) bestanden aus Silikat, 3 Steine waren aus verfestigtem Blut, 2 bestanden aus Cystin und einer aus Xanthin. 40% der Uretersteine bestanden aus Struvit. Hauskatzen hatten signifikant seltener Kalziumoxalatsteine als British Shorthair oder Perser Katzen. Katzen mit Kalziumoxalatsteinen waren älter und Katzen mit Struvitsteinen waren jünger als andere betroffene Katzen. Weibliche und männliche Katzen waren gleich häufig von Steinen betroffen. Im Vergleich zu Studien aus anderen Ländern, kamen in der Schweiz Silikatsteine häufiger vor und Uretersteine bestanden häufiger aus Struvit. Die vorliegende Untersuchung zeigt, dass Vorkommen und Häufigkeit von Harnsteinen bei Katzen in der Schweiz nur geringe Unterschiede zu Studien aus anderen Ländern aufweisen.. Dans le présent travail, on résume les données relatives à la composition des calculs urinaires chez les chats en Suisse ainsi que les données épidémiologiques de ces animaux entre 2002 et 2009. Parmi les 884 calculs analysés, 50% (n=441) étaient composés d’oxalate de calcium, 45% (n=398) de struvite, 3% (n=18) d’urate d’ammonium, 1% (n=12) étaient des calculs mixtes 1% (n=9) se composaient de silicate, 3 calculs étaient formé de sang aggloméré, 2 étaient composés de cystine et un de xanthine. 40% des calculs urétraux se composaient de struvite. Les chats de maison avaient significativement moins de calculs d’oxalate de calcium que les British Shorthair ou les Persans. Les chats présentant des calculs d’oxalate de calcium étaient plus âgés et ceux présentant des struvites plus jeunes que tous les autres chats atteints. Les femelles et les mâles souffraient de calculs de façon équivalente. En comparaison avec des études menées dans d’autres pays, les calculs de silicate étaient plus fréquents en Suisse et les calculs urétraux se composaient plus souvent de struvite. Cette étude démontre que la survenue et la fréquence de calculs urinaires chez les chats en Suisse ne présente que peu de différence avec les études faites dans d’autres pays.. In questo studio vengono riassunti i dati sulla composizione degli uroliti nei gatti e i dati epidemiologici degli stessi in Svizzera dal 2002 al 2009. Il 50% (n=441) degli 884 calcoli analizzati era composto di ossalato di calcio, il 45% (n=398) di struvite, il 3% (n=18) di urato di ammonio, l’1% (n=12) di calcoli misti, l’1% (n=9) di silicati, 3 calcoli erano di sangue coagulato, 2 di cisteina e 1 di xantina. Il 40% dei calcoli nell’uretere erano composti da struvite. I gatti domestici avevano significativamente meno calcoli composti da ossalato di calcio che il British Shorthair o i gatti persiani. Paragonando i gatti colpiti, quelli affetti da calcoli di ossalato di calcio erano anziani mentre quelli con calcoli di struvite giovani. Il sesso dei gatti non era un fattore che influenzava più o meno la presenza di calcoli. Rispetto agli studi di altri Paesi, in Svizzera i calcoli urinari più comuni sono composti da silicati mentre quelli dell’uretere da struvite. Il presente studio dimostra che la prevalenza e l’incidenza dei calcoli urinari nei gatti in Svizzera è solo di poco differente che in altri Paesi.

Topics: Animals; Calcium Oxalate; Cat Diseases; Cats; Female; Kidney Calculi; Male; Silicon Dioxide; Struvite; Switzerland; Uric Acid; Urolithiasis

We describe a case of a large amount of mineralised material, presumed to be struvite crystals, within the urinary bladder of a cat with feline idiopathic cystitis. The presence of this material coincided with episodes of lower urinary tract signs in this cat over a 2-year period.. Although struvite crystalluria is widely considered to be clinically insignificant, this generalisation may not be true for all cats with lower urinary tract disease. Imaging of the urinary tract is recommended in all cats with lower urinary tract signs.

Topics: Animals; Cat Diseases; Cats; Cystitis; Magnesium Compounds; Male; Phosphates; Struvite; Ultrasonography; Urethra; Urinary Bladder

Topics: Animal Feed; Animal Nutrition Sciences; Animal Nutritional Physiological Phenomena; Animals; Calcium Oxalate; Cat Diseases; Cats; Magnesium Compounds; Nephrolithiasis; Phosphates; Prevalence; Struvite; Urolithiasis

To evaluate the influence of acidifying or alkalinizing diets on bone mineral density and urine relative supersaturation (URSS) with calcium oxalate and struvite in healthy cats.. 6 castrated male and 6 spayed female cats.. 3 groups of 4 cats each were fed diets for 12 months that differed only in acidifying or alkalinizing properties (alkalinizing, neutral, and acidifying). Body composition was estimated by use of dual energy x-ray absorptiometry, and 48-hour urine samples were collected for URSS determination.. Urine pH differed significantly among diet groups, with the lowest urine pH values in the acidifying diet group and the highest values in the alkalinizing diet group. Differences were not observed in other variables except urinary ammonia excretion, which was significantly higher in the neutral diet group. Calcium oxalate URSS was highest in the acidifying diet group and lowest in the alkalinizing diet group; struvite URSS was not different among groups. Diet was not significantly associated with bone mineral content or density.. Urinary undersaturation with calcium oxalate was achieved by inducing alkaluria. Feeding an alkalinizing diet was not associated with URSS with struvite. Bone mineral density and calcium content were not adversely affected by diet; therefore, release of calcium from bone caused by feeding an acidifying diet may not occur in healthy cats.

Topics: Absorptiometry, Photon; Animal Feed; Animals; Body Composition; Bone Density; Calcium Oxalate; Cat Diseases; Cats; Diet; Female; Hydrogen-Ion Concentration; Magnesium Compounds; Male; Nephrolithiasis; Phosphates; Struvite

Evaluation of urinary stones analysed between 1981 and 2008 in cats and comparison with data submitted, such as breed, age, sex and body weight.. Over the given years 5173 feline uroliths from cats in Germany and some neighbouring countries were analysed. From the forms submitted the following data was obtained for most cats: breed, age, sex, body weight, obesity status and location of the urinary stone(s). All uroliths were analysed by infrared spectroscopy. Uroliths containing at least 70% of a single mineral were classified as being of that type.. The cats with urolithiasis belonged to 25 different breeds. The most common breed was the European shorthair (64.3%) followed by Persian (15.2%), British shorthair (3.9%), Chartreux (1.7%), Maine Coon (1.5%) and Siamese (1.1%). Most animals were neutered or castrated (81.8%). Tom cats were significantly more frequently affected than female cats. The mean age (7 years) was virtually identical between both sexes, but varied between different stone types. Cats with struvite stones were significantly younger than cats with calcium oxalate stones (6.6 versus 7.6 years). Most urinary stones were retrieved from the bladder and/or urethra (93%). Over the entire time period (1981-2008) struvite (51.2%) and calcium oxalate (38.7%) stones were the two most common urolith types. Percent calcium oxalate stones increased significantly over time and were seen more often in 2008 than struvite stones (48.6% versus 43.4%). Amongst other urinary stones, ammonium urate (1.7%), carbonate apatite (1.7%), cystine (0.5%) and xanthine (0.3%) uroliths were analysed.. While struvite and calcium oxalate stones are presently found at approximately equal frequency in cats, various different urinary stones types can also occur in this species. Epidemiological knowledge of urinary stones is crucial as a basis for adequate therapy and prevention.

Topics: Age Factors; Animals; Breeding; Calcium Oxalate; Cat Diseases; Cats; Europe; Female; Germany; Magnesium Compounds; Male; Phosphates; Sex Factors; Spectrophotometry, Infrared; Struvite; Urinary Calculi

To confirm that the predominant mineral type in naturally occurring uroliths in ferrets is struvite; to determine whether age, breed, sex, reproductive status, geographic location, season, and anatomic location are risk factors associated with urolith formation in ferrets; to compare features of struvite uroliths in cats with those in ferrets; and to determine whether there is a logical evidence-based rationale for clinical trials of the safety and efficacy of diet-induced dissolution of struvite uroliths in ferrets.. Retrospective case-control study.. 408 ferrets with uroliths (272 struvite uroliths) from the Minnesota Urolith Center, and 6,528 control ferrets from the Veterinary Medical Database.. Historical information was obtained about each ferret. The association between proposed risk factors and outcome (struvite urolith formation) was assessed.. Sterile struvite was the predominant mineral in uroliths in ferrets. Neutered male ferrets had a significantly increased risk of developing sterile struvite uroliths. A significant association was also found between increasing age and the detection of struvite uroliths. Struvite uroliths in ferrets were more likely to be retrieved from the lower urinary tract than from the upper urinary tract.. Knowledge of predominant mineral type in uroliths along with insight into etiologic, demographic, and environmental risk and protective factors for urolithiasis may facilitate development of surveillance strategies that result in earlier detection of uroliths in ferrets. Modification of risk factors, including dietary risk factors, may help to minimize urolith formation, dissolve existing uroliths, and minimize urolith recurrence.

Topics: Animals; Case-Control Studies; Cat Diseases; Cats; Female; Ferrets; Logistic Models; Magnesium Compounds; Male; Odds Ratio; Phosphates; Retrospective Studies; Risk Factors; Seasons; Struvite; Urolithiasis

Feline idiopathic cystitis (FIC) is the most common cause of feline lower urinary tract disease (FLUTD). This retrospective, case-controlled study evaluated possible risk factors associated with FIC and compared different clinical presentations in 64 cats with FIC. Several risk factors known to be involved in FLUTD were identified as playing a role in FIC. Of the stressful situations considered, most did not occur with increased frequency in cats with FIC compared to controls, except for a house move. The presence of pyuria, haematuria and an increased urine protein:creatinine ratio were significantly higher in obstructed males compared with non-obstructed males. An obstruction was significantly more likely in cats with struvite crystalluria compared with cats without struvite crystalluria. These findings suggest that urethral plugs might be an important cause or contributing factor of obstruction in FIC. Episodes of FIC seem to occur mainly in susceptible cats in combination with a deficient environment.

Topics: Animals; Belgium; Breeding; Case-Control Studies; Cat Diseases; Cats; Cystitis; Female; Magnesium Compounds; Male; Phosphates; Retrospective Studies; Risk Factors; Struvite

To learn more about the biomineralization process of struvite in ruminants, a seldom noticeable crystal, struvite-K, was investigated in six goats in which urolithiasis was induced by feeding a cottonseed meal and rice straw diet supplemented with MgO. The compositions of crystals and calculi were studied by chemical qualitative analysis and X-ray energy dispersive spectrometry (EDS). The activity product (AP) and relative supersaturation (RSS) of magnesium ammonium phosphate (MAP) and potassium magnesium phosphate (MKP) were calculated to compare the difference of crystals formed in this process. The results showed that calculi consisted of MAP with a little MKP. Crystals in the urine consisted of MAP and MKP before stone formation, but crystals in urine after stone formation mainly consisted of MKP. The AP and RSS of MAP and MKP significantly decreased after stone formation. It was concluded that MAP and MKP may coexist in the crystals of urine before struvite calculi formation but MKP did not precipitate to struvite calculi and was separated out as crystal sedimentation of urine. The changes of crystallization of MAP and MKP contributed partially to the supersaturation status of MAP and MKP during struvite stone formation.

Topics: Animals; Cat Diseases; Cats; Dog Diseases; Dogs; Goat Diseases; Goats; Magnesium Compounds; Magnesium Oxide; Phosphates; Potassium Compounds; Struvite; Urolithiasis

To determine frequency of and interval until recurrence after initial ammonium urate, calcium oxalate, and struvite uroliths in cats and whether breed, age, or sex was associated with increased risk for urolith recurrence.. Case-control study.. 4,435 cats with recurrent uroliths.. To identify recurrence of uroliths in cats for which uroliths were submitted for analysis at the Minnesota Urolith Center in 1998, the facility's database was searched for urolith resubmissions from the same cats between 1998 and 2003. Risk factors and differences in mean interval until recurrence were assessed.. Of 221 cats with ammonium urate uroliths in 1998, 29 (13.1%) had a first and 9 (4.1%) had a second recurrence. Mean interval until recurrence was 22 and 43 months for the first and second recurrence, respectively. Of 2,393 cats with calcium oxalate uroliths in 1998, 169 (7.1%) had a first, 15 (0.6%) had a second, and 2 (0.1%) had a third recurrence. Mean interval until recurrence was 25, 38, and 48 months for the first, second, and third recurrence, respectively. Of 1,821 cats with struvite uroliths in 1998, 49 (2.7%) had a first and 3 (0.2%) had a second recurrence. Mean interval until recurrence was 29 months for first and 40 months for second recurrences.. These results provided insights into the frequency of urolith recurrence in cats. Because some uroliths associated with recurrent episodes probably were not submitted to our facility, our data likely represented an underestimation of the actual recurrence rate.

Topics: Animals; Calcium Oxalate; Case-Control Studies; Cat Diseases; Cats; Magnesium Compounds; Odds Ratio; Phosphates; Recurrence; Struvite; Uric Acid; Urinary Calculi; Urolithiasis

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.

Topics: Age Factors; Animals; Breeding; Calcium Oxalate; Canada; Cat Diseases; Cats; Dog Diseases; Dogs; Female; Magnesium Compounds; Male; Phosphates; Risk Factors; Species Specificity; Struvite; Urinary Calculi; Urolithiasis

To characterize and evaluate risk factors for suture-associated cystoliths in dogs and cats.. 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.. 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.. 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.. 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.

Topics: Animals; Breeding; Calcium Oxalate; Case-Control Studies; Cat Diseases; Cats; Dog Diseases; Dogs; Female; Magnesium Compounds; Male; Odds Ratio; Phosphates; Prevalence; Recurrence; Retrospective Studies; Risk Factors; Sex Factors; Struvite; Sutures; Urinary Bladder Calculi

Factors affecting struvite, a magnesium-ammonium-phosphate complex (MgNH(4)PO(4).6H(2)O), in feline urine were evaluated. Incubation of just "urine mineral (UM)" solution, in which mineral concentrations are compatible with those in feline urine, for 4 h at 37 degrees C did not induce the formation of crystals. Similarly, incubation of urine alone did not produce crystals. However, struvite crystals were formed by the addition of urine to UM solution. Mg, NH(3) and P were all required for urine-induced struvite crystallization. The lower molecular weight (LMW) fraction of urine was essential for struvite crystal formation, and the higher molecular weight (HMW) fraction enhanced formation of LMW-induced struvite crystals. The effects of urine proteins further fractionated by column chromatography were examined. A protein at >250 kDa and cauxin, a major urine protein recently identified as a regulator of felinine production, potentiated struvite crystal formation induced by the LMW fraction. In contrast, Tamm-Horsfall glycoprotein, a urine protein thought to promote struvite crystallization, did not have this activity. The present study reveals a novel mechanism of feline struvite crystallization.

Topics: Ammonia; Animals; Carboxylesterase; Cat Diseases; Cats; Crystallization; Magnesium; Magnesium Compounds; Male; Molecular Weight; Phosphates; Phosphorus; Proteins; Struvite; Urolithiasis

From 1994 to 2004, Hill's Pet Nutrition received 4495 canine (65%) and feline (35%) uroliths from Benelux veterinary practitioners. They were sent to the Minnesota Urolith Center, USA for analysis. In 1994, 110 uroliths were analysed - 85% from dogs - and in 2003, 1067 uroliths were analysed - 59% from dogs. During this period, substantial changes were observed in composition. In 1994, 77% of the cats had uroliths composed of struvite, and 12% had uroliths composed of calcium oxalate. In 2003, feline uroliths were composed of 32% struvite, and 61% calcium oxalate. The same evolution was observed in the dogs. In 1994, 51% of canine uroliths were composed of struvite, and 33% of calcium oxalate. In 2003, 40% had struvite uroliths, and 46% had calcium oxalate uroliths. A significant effect of the size, the breed, and the gender were noticed in the dogs. The mean age of uroliths appearance was 7.3 years in the dogs and 7.2 years in the cats. The findings are similar to those previously published in the USA.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Belgium; Breeding; Calcium Oxalate; Cat Diseases; Cats; Dog Diseases; Dogs; Female; Luxembourg; Magnesium Compounds; Male; Netherlands; Phosphates; Retrospective Studies; Sex Factors; Struvite; Urinary Calculi; Urolithiasis

To determine trends in urolith composition in cats.. Retrospective case series.. 5,230 uroliths.. The laboratory database for the Gerald V. Ling Urinary Stone Analysis Laboratory was searched for all urolith submissions from cats from 1985 through 2004. Submission forms were reviewed, and each cat's age, sex, breed, and stone location were recorded.. Minerals identified included struvite, calcium oxalate, urates, dried solidified blood, apatite, brushite, cystine, silica, potassium magnesium pyrophosphate, xanthine, and newberyite. During the past 20 years, the ratio of calcium oxalate stones to struvite stones increased significantly. When only the last 3 years of the study period were included, the percentage of struvite stones (44%) was higher than the percentage of calcium oxa-late stones (40%). The most common location for both types of uroliths was the bladder. The number of calcium oxalate-containing calculi in the upper portion of the urinary tract increased significantly during the study period. The number of apatite uroliths declined significantly and that of dried solidified blood stones increased significantly, compared with all other stone types. No significant difference in the number of urate stones was detected.. The increasing proportion of calcium oxalate uroliths was in accordance with findings from other studies and could be a result of alterations in cats' diets. However, the decreased percentage of calcium oxalate calculi and increased percentage of struvite calculi observed in the last 3 years may portend a change in the frequency of this type of urolith.

Topics: Age Factors; Animal Feed; Animals; Breeding; Calcium Oxalate; Calcium Phosphates; Cat Diseases; Cats; Female; Magnesium Compounds; Male; Phosphates; Retrospective Studies; Sex Factors; Struvite; Ureteral Calculi; Urolithiasis

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.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Diet; Female; Hydrogen-Ion Concentration; Magnesium Compounds; Male; Phosphates; Prospective Studies; Struvite; Treatment Outcome; Urinalysis; Urinary Bladder Calculi

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.

Topics: Age Factors; Animals; Breeding; Calcium Oxalate; Canada; Cat Diseases; Cats; Female; Magnesium Compounds; Male; Phosphates; Risk Factors; Sex Factors; Struvite; Urethral Obstruction; Urinary Calculi

To determine hospital proportional morbidity rates (HPMR) for urethral obstructions, urethral plugs or urethroliths, and urethrostomies in cats in veterinary teaching hospitals (VTH) in Canada and the United States between 1980 and 1999.. Epidemiologic study.. 305,672 cats evaluated at VTH.. Yearly HPMR were determined for cats with urethral obstructions, urethral plugs or urethroliths, or urethrostomies from data compiled by the Purdue Veterinary Medical Database. The test for a linear trend in proportions was used.. Urethral obstructions were reported in 4,683 cats. Yearly HPMR for urethral obstructions declined from 19 cases/1,000 feline evaluations in 1980 to 7 cases/1,000 feline evaluations in 1999. Urethral plugs or urethroliths affected 1,460 cats. Yearly HPMR for urethral plugs or urethroliths decreased from 10 cases/1,000 feline evaluations in 1980 to 2 cases/1,000 feline evaluations in 1999. A total of 2,359 urethrostomies were performed. Yearly HPMR for urethrostomies decreased from 13 cases/1,000 feline evaluations in 1980 to 4 cases/1,000 feline evaluations in 1999.. Frequency of feline urethrostomies performed at VTH in Canada and the United States declined during the past 20 years and paralleled a similar decline in frequency of urethral obstructions and urethral plugs or urethroliths. These trends coincide with widespread use of diets to minimize struvite crystalluria in cats, which is important because struvite has consistently been the predominant mineral in feline urethral plugs during this period.

Topics: Animal Feed; Animals; Canada; Cat Diseases; Cats; Epidemiologic Studies; Female; Hospitals, Animal; Magnesium Compounds; Male; Morbidity; Ostomy; Phosphates; Retrospective Studies; Struvite; United States; Urethral Diseases; Urethral Obstruction; Urinary Calculi

Feeding dry foods supplemented with urine acidifier (D,L-methionine (Met) or ammonium chloride) decreased urinary pH and struvite activity product in clinically normal cats. As a result, the number of struvite crystals in urine was greatly reduced. Supplementation with 3% Met but not 1% Met caused decrease in the urinary concentration of sediment, which resulted from a reduction in the HCl-soluble fraction. The concentration of HCl-insoluble sediment was not affected by supplementation with the urine acidifier.

Topics: Ammonium Chloride; Animal Feed; Animals; Cat Diseases; Cats; Cross-Over Studies; Dietary Supplements; Female; Hydrogen-Ion Concentration; Magnesium Compounds; Male; Methionine; Phosphates; Struvite; Urinary Calculi

To identify dietary factors associated with the increase in occurrence of calcium oxalate (CaOx) uroliths and the decrease in occurrence of magnesium ammonium phosphate (MAP) uroliths in cats.. Case-control study.. 173 cats with CaOx uroliths, 290 cats with MAP uroliths, and 827 cats without any urinary tract diseases.. Univariate and multivariate logistic regression were performed.. Cats fed diets low in sodium or potassium or formulated to maximize urine acidity had an increased risk of developing CaOx uroliths but a decreased risk of developing MAP uroliths. Additionally, compared with the lowest contents, diets with the highest moisture or protein contents and with moderate magnesium, phosphorus, or calcium contents were associated with decreased risk of CaOx urolith formation. In contrast, diets with moderate fat or carbohydrate contents were associated with increased risk of CaOx urolith formation. Diets with the highest magnesium, phosphorus, calcium, chloride, or fiber contents and moderate protein content were associated with increased risk of MAP urolith formation. On the other hand, diets with the highest fat content were associated with decreased risk of MAP urolith formation.. Results suggest that diets formulated to contain higher protein, sodium, potassium, moisture, calcium, phosphorus, and magnesium contents and with decreased urine acidifying potential may minimize formation of CaOx uroliths in cats. Diets formulated to contain higher fat content and lower protein and potassium contents and with increased urine acidifying potential may minimize formation of MAP uroliths.

Topics: Animals; Calcium Oxalate; Calcium, Dietary; Case-Control Studies; Cat Diseases; Cats; Diet; Dietary Carbohydrates; Dietary Fats; Dietary Fiber; Dietary Proteins; Female; Hydrogen-Ion Concentration; Logistic Models; Magnesium; Magnesium Compounds; Male; Phosphates; Phosphorus, Dietary; Potassium, Dietary; Sodium, Dietary; Struvite; Surveys and Questionnaires; Urinalysis; Urinary Calculi; Water

Urinalysis was performed on 41 cats with no history of urinary tract disease. Samples were divided into aliquots, stored under differing condition and then examined for the presence of crystalluria. Crystalluria was detected in at least one stored sample in 92% of cats fed a mixed wet/dry food diet compared to 24% in the fresh sample. Crystalluria was not detected in any sample or aliquot from cats fed all wet food diets.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Female; Kidney Calculi; Magnesium Compounds; Male; Phosphates; Predictive Value of Tests; Specimen Handling; Struvite

To determine whether breed, age, sex, or reproductive status (i.e., neutered versus sexually intact) was associated with the apparent increase in prevalence of calcium oxalate (CaOx) uroliths and the decrease in prevalence of magnesium ammonium phosphate (MAP) uroliths in cats over time.. Case-control study.. Case cats consisted of cats with CaOx (n = 7,895) or MAP (7,334) uroliths evaluated at the Minnesota Urolith Center between 1981 and 1997. Control cats consisted of cats without urinary tract disease admitted to veterinary teaching hospitals in the United States and Canada during the same period (150,482).. Univariate and multivariate logistic regression were performed.. British Shorthair, Exotic Shorthair, Foreign Shorthair, Havana Brown, Himalayan, Persian, Ragdoll, and Scottish Fold cats had an increased risk of developing CaOx uroliths, as did male cats and neutered cats. Chartreux, domestic shorthair, Foreign Shorthair, Himalayan, Oriental Shorthair, and Ragdoll cats had an increased risk of developing MAP uroliths, as did female cats and neutered cats. Cats with CaOx uroliths were significantly older than cats with MAP uroliths.. Results suggest that changes in breed, age, sex, or reproductive status did not contribute to the apparent reciprocal relationship between prevalences of CaOx and MAP uroliths in cats during a 17-year period. However, cats of particular breeds, ages, sex, and reproductive status had an increased risk of developing CaOx and MAP uroliths.

Topics: Age Factors; Animals; Breeding; Calcium Oxalate; Case-Control Studies; Cat Diseases; Cats; Female; Logistic Models; Magnesium Compounds; Male; Odds Ratio; Phosphates; Risk Factors; Sex Factors; Struvite; Time Factors; Urinary Calculi

Topics: Animal Nutritional Physiological Phenomena; Animals; Calcium Oxalate; Cat Diseases; Cats; Cystine; Diet; Dog Diseases; Dogs; Magnesium Compounds; Phosphates; Quaternary Ammonium Compounds; Struvite; Uric Acid; Urinary Calculi

To identify the underlying cause of clinical signs in cats with nonobstructive diseases of the bladder and urethra.. Prospective case series.. 109 cats examined by the urology service of The Ohio State University's veterinary teaching hospital because of stranguria, hematuria, pollakiuria, or urination in inappropriate locations.. History was obtained and a CBC, serum biochemical analyses, serologic tests for FeLV and feline immunodeficiency virus, urinalysis, bacterial culture of urine, and contrast radiography or urethrocystoscopy (females only) were performed.. 16 cats had cystic calculi: 8 had struvite uroliths, 7 had calcium oxalate uroliths, and 1 had a urolith of unknown composition in conjunction with an anatomic defect. Anatomic defects, including diverticulae, urethral strictures, and a malpositioned urethra, were identified in 12 cats. A urinary tract infection was identified in 1 cat, and neoplasia was diagnosed in 2. One of the cats with neoplasia also had a struvite urolith. The remaining 80 cats did not have an anatomic defect, urolith, or tumor. Ten of these cats also did not have radiographic or cystoscopic abnormalities and were presumed to have a behavioral disorder. The remaining 70 cats had radiographic or cystoscopic abnormalities, and idiopathic cystitis was diagnosed. In 14 of the cats with idiopathic cystitis, results of a urinalysis were normal. Cats with idiopathic cystitis were significantly more likely to eat dry food exclusively (59%) than were cats in the general population (19%).. Results suggest that idiopathic cystitis occurs commonly in cats with stranguria, hematuria, pollakiuria, or inappropriate elimination and is associated with consumption of dry foods. Contrast radiography or cystoscopy is necessary for differentiating idiopathic cystitis from behavioral disorders in some cats.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Cystitis; Cystoscopy; Diverticulum; Female; Hematuria; Hydrogen-Ion Concentration; Magnesium Compounds; Male; Phosphates; Prospective Studies; Proteinuria; Specific Gravity; Struvite; Urethra; Urethral Stricture; Urinary Bladder Calculi; Urinary Bladder Diseases; Urine; Urologic Diseases

to test the hypothesis that breed, sex and age of cats, and anatomic location of uroliths are risk factors for calcium oxalate and magnesium ammonium phosphate urolithiasis.. Retrospective case-control study.. Records of 3,498 feline urolith accessions submitted between September 1982 and September 1992.. Mineral composition of feline uroliths was quantitatively analyzed. Odds ratios and 95% confidence intervals were calculated for breed, sex, age, and urolith location as risk factors for calcium oxalate and magnesium ammonium phosphate urolith formation. The population at risk was defined as all cats for which that type of urolith had been submitted. The control population was all cats for which uroliths had been submitted, excluding cats with the type of urolith being evaluated.. Burmese, Persian, and Himalayan breeds were at higher risk for developing calcium oxalate uroliths, but at reduced risk for developing magnesium ammonium phosphate uroliths. Compared with females, neutered male cats had a higher risk for developing calcium oxalate uroliths, but a reduced risk for developing magnesium ammonium phosphate uroliths. The risk for calcium oxalate urolith formation increased with age. One- to 2-year-old female cats had the highest risk for magnesium ammonium phosphate uroliths. Uroliths removed from the kidneys were more likely to be composed of calcium oxalate than of magnesium ammonium phosphate.. Breed, sex, and age of cats, and anatomic location of uroliths should be considered when evaluating risk of calcium oxalate and magnesium ammonium phosphate urolithiasis in urolith-forming cats.

Topics: Age Factors; Animals; Breeding; Calcium Oxalate; Case-Control Studies; Cat Diseases; Cats; Confidence Intervals; Female; Magnesium Compounds; Male; Odds Ratio; Phosphates; Prevalence; Retrospective Studies; Risk Factors; Sex Factors; Struvite; Urinary Calculi

To elucidate the ultrastructural details of struvite-containing urinary calculi from cats.. Specimens studied were inclusive of the range of textures visible during preliminary analysis by use of a stereoscopic dissecting microscope. Textural types, which were used to infer crystal growth conditions, were differentiated with regard to crystal habit, crystal size, growth orientation, and primary porosity.. Thirty specimens were selected from a collection of approximately 1,600 feline urinary calculi: 20 of these were composed entirely of struvite, and 10 consisted of struvite and calcium phosphate (apatite).. Qualitative and quantitative analyses of specimens included use of plain and polarized light microscopy, x-ray diffractometry, scanning electron microscopy with backscattered electron imagery, x-ray fluorescence scans, and electron probe microanalysis.. Four textural types were recognized among struvite calculi, whereas 2 textural types of struvite-apatite calculi were described.. The presence of minute, well interconnected primary pores in struvite-containing urinary calculi from cats is an important feature, which may promote possible interaction of calculi with changes in urine composition.. Primary porosity, which can facilitate interaction between the calculus and changing urine composition, may explain the efficacy of dietary or medicinal manipulations to promote the dissolution of struvite-containing uroliths from this species.

Topics: Animals; Apatites; Calcium; Cat Diseases; Cats; Electron Probe Microanalysis; Magnesium; Magnesium Compounds; Microscopy, Electron, Scanning; Microscopy, Polarization; Phosphates; Potassium; Spectrometry, X-Ray Emission; Struvite; Urinary Calculi; X-Ray Diffraction

To elucidate the ultrastructural details of struvite-containing urinary calculi from dogs.. 38 specimens were selected from a collection of approximately 13,000 canine urinary calculi: 18 of these were composed entirely of struvite, and 20 consisted of struvite and calcium phosphate (apatite).. Qualitative and quantitative analyses of specimens included use of plain and polarized light microscopy, x-ray diffractometry, scanning electron microscopy with backscattered electron imagery, x-ray fluorescence scans, and electron microprobe analysis.. 4 textural types were recognized among struvite calculi, and 4 textural types of struvite-apatite calculi were described. Evidences of calculus dissolution were described from 4 calculi studied.. The presence of small, well interconnected primary pores in struvite-containing urinary calculi from dogs appears to be a significant factor in determining the possible interaction of calculi with changes in the urine composition. The progress of dissolution from the calculus surface to the calculus interior appears to be largely affected by the primary porosity originally present between crystals forming the calculus framework. Apatite was observed to be more resistant to dissolution than struvite.. The prevalence of fine concentric laminations having low porosity, and the common occurrence of apatite among struvite-containing urinary calculi from dogs may be 2 reasons why the efficacy of dietary and medicinal manipulations in dissolving urinary calculi is greater among cats than it is among dogs.

Topics: Animals; Calcium Phosphates; Cat Diseases; Cats; Dog Diseases; Dogs; Electron Probe Microanalysis; Magnesium Compounds; Microscopy, Electron, Scanning; Phosphates; Polarography; Spectrometry, X-Ray Emission; Struvite; Urinary Calculi; X-Ray Diffraction

Six healthy adult cats were fed a basal minced beef meat and rice diet with varying amounts or combinations of acidifying and alkalizing additives (ammonium chloride, calcium and sodium carbonate). The base excess in the food (mmol/kg dry matter) was calculated (data on food compounds in g/kg dry matter) as follows: base excess = 49.9*Ca + 82.3*Mg + 43.5*Na + 25.6*K - 64.6*P - 13.4*Met-16.6*Cystine -28.2*Cl. It amounted to between +305 and -1079 mmol/kg dry matter. Urine and blood pH as well as balance of minerals and water were determined in the cats. The mean urine pH ranged between 6.1 and 7.8. There was a highly significant correlation between the base excess in the food and the mean urine pH. The regression line was linear down to a base excess in the diet of about -400 to -500 mmol/kg dry matter and a pH in the urine of 6.2. The postprandial increase of urine pH was suppressed either by large amounts of ammonium chloride (> 780 mmol/kg dry matter) alone or in combination with calcium carbonate, but not in combination with sodium carbonate. The relationship between the decrease of the blood pH and the amount of ammonium chloride added to the diet was more marked than the relationship between blood pH and base excess in the food. In order to avoid health risks by long term application of acidifying diets it is recommended to formulate struvite diets with low base excess in such a way, that they contain as few alkalizing compounds as possible, which must be neutralized by acidifiers.

Topics: Acid-Base Equilibrium; Ammonium Chloride; Animals; Carbonates; Cat Diseases; Cats; Food Additives; Magnesium Compounds; Minerals; Phosphates; Struvite; Urinary Calculi

The efficacy of a diet designed to facilitate dissolution of feline magnesium ammonium phosphate (struvite) uroliths was evaluated in 30 cases of urolithiasis, sterile struvite uroliths dissolved in a mean of 36 days after initiation of dietary treatment. In 5 cases of urolithiasis, struvite urocystoliths associated with urease-negative bacterial urinary tract infection dissolved in a mean of 23 days after initiation of dietary and antimicrobial treatment. In 3 cases of urolithiasis, struvite urocystoliths associated with urease-positive staphylococcal urinary tract infection dissolved in a mean of 79 days after initiation of dietary and antimicrobial treatment. Dissolution of uroliths in cats fed the treatment diet was associated with concomitant remission of dysuria, hematuria, and pyuria, and reduction in urine pH and struvite crystalluria. In one case, a urocystolith composed of 100% ammonium urate, and in another case, a urolith composed of 60% calcium phosphate, 20% calcium oxalate, and 20% magnesium ammonium phosphate did not dissolve.

Topics: Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Animals; Cat Diseases; Cats; Clavulanic Acids; Drug Therapy, Combination; Female; Follow-Up Studies; Hydrogen-Ion Concentration; Magnesium; Magnesium Compounds; Male; Phosphates; Radiography; Recurrence; Specific Gravity; Struvite; Time Factors; Urinary Calculi; Urinary Tract Infections

One hundred fifty specimens of urinary calculi from 150 cats were analyzed by at least 1 of 4 quantitative methods. Struvite (magnesium ammonium phosphate) was the predominant mineral substance encountered, with 104 (69%) of the calculi being composed entirely of struvite and 23 (15%) being composed partially of struvite. Most (93%) of the calculi were located in the urinary bladder. Growth of bacteria was observed in samples from calculi or urine from 30 (41%) of 74 cats. Coagulase-positive staphylococci were isolated from the urine or calculi from 17 cats (45% of bacteria isolated). Ten other bacterial species were isolated. Median and mean ages of the cats were 5.0 and 5.1 years, respectively. Domestic short-hair and domestic longhair breeds predominated. Fifty-seven percent of the calculi came from females, 43% from males. The distribution by gender did not differ significantly (P greater than 0.2) among the 3 groups (domestic shorthair, domestic longhair, and other). However, the distribution of struvite calculi differed significantly (chi 2 = 15.5, P less than 0.001) by age and gender; among cats less than or equal to 2 years of age, males predominated 2:1 over females, and among cats greater than 2 years of age, females predominated by nearly 3:1 over males. When compared with the general population, females greater than 2 years old were significantly (chi 2 = 15.4, P less than 0.001) overrepresented.

Topics: Age Factors; Animals; Apatites; Bacteria; Bacteriuria; Breeding; Calcium Oxalate; Cat Diseases; Cats; Female; Magnesium; Magnesium Compounds; Male; Phosphates; Sex Factors; Struvite; Uric Acid; Urinary Calculi

Eighteen male cats were fed either a canned complete diet or a commercially available dry pelleted diet or the same dry diet containing 1.6 per cent ammonium chloride. The daily food and water intake of four of these cats was measured. Urine samples were taken at random and the pH and the presence of struvite crystals in their sediment estimated. In some samples in which the pH was less than 7.0, and struvite crystals were absent, the pH was increased to 7.0 and any sediment was examined for struvite. No spontaneous struvite was seen in urine samples (pH 5.8) from cats fed the canned complete diet but when its pH was raised to 7.0, 46 per cent of these samples showed struvite. Cats fed the dry pelleted diet had urine of higher pH (7.55) and 78 per cent of the samples contained struvite crystals. Cats fed this diet supplemented with ammonium chloride had a urine pH of 5.97 and only 9 per cent contained struvite crystals but when the pH was adjusted to 7.0 all the samples showed struvite crystals. Energy intake was similar on all three diets but the intake of dry matter was greater on the dry diets. Liquid water intake was greater on the dry diets but total water intake was greatest on the canned complete diet. The intake of magnesium, calcium and phosphate was greater on the dry diets. It is concluded that urine pH is a more important controller of struvite precipitation than mineral intake.

Topics: Animal Feed; Animals; Cat Diseases; Cats; Diet; Hydrogen-Ion Concentration; Magnesium; Magnesium Compounds; Male; Phosphates; Struvite; Urinary Calculi

In three separate experiments nine male cats were fed either a canned complete diet or a commercially available dry pelleted diet or the same dry diet containing 1.6 per cent ammonium chloride for seven days and then fasted for 20 hours. Then ad libitum feeding was continued and urine samples were taken at four-hour intervals for 12 hours and a final sample 12 hours later. Urine pH and the presence of struvite crystals in urine sediment were evaluated. The food and water intake of four of the nine cats was measured at the time of urine collection. After the fast, urine pH was raised, even after feeding the dry diet supplemented with ammonium chloride. A post prandial rise in urine pH was also seen on all three diets. After feeding the dry diet the postprandial peak pH was 7.97 and struvite occurred spontaneously. Urine pH after feeding the dry diet supplemented with ammonium chloride peaked at 7.75 then fell to 6.1 12 hours after the start of feeding. Struvite occurred spontaneously at all times until the pH reached 6.1 but when the pH of urine was raised to 7.0 the struvite crystallised. Urine pH on the canned complete diet peaked at 6.8 then fell to 5.8; struvite did not occur spontaneously but when urine pH was raised to 7.0 struvite crystallised except at the eighth and 12th hour sampling. These data show that fasting initiates a post prandial rise in urine pH and struvite crystalluria even when a normally effective urinary acidifier is used.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Ammonium Chloride; Animal Feed; Animals; Cat Diseases; Cats; Drinking; Eating; Fasting; Hydrogen-Ion Concentration; Magnesium; Magnesium Compounds; Male; Phosphates; Struvite; Urinary Calculi

Aggregates of struvite crystals caused urethral obstruction in a high percentage of cats fed moist and dry diets supplemented with Mg oxide. Some of the diets were associated with cystolith formation as well. The percentage of Mg in the experimental diets was a misleading indicator of Mg intake because of differences between moist and dry diets in their caloric density. Magnesium homeostasis was maintained in cats ingesting large quantities of Mg. Tissue (kidney, muscle, and rib) concentrations of Mg were the same in cats fed high Mg and control diets. Plasma Mg concentration was increased only in cats ingesting the largest amount of Mg. Magnesium homeostasis was maintained by a marked increase in urine Mg excretion. However, urine Mg concentration was not directly related to Mg intake, apparently because of differences between diets in intestinal absorption of Mg. Urethral obstruction of experimental cats was not associated with a transient increase in Mg intake, nor did obstructing cats have higher urine Mg concentrations than did nonobstructing cats fed the same diet. This observation indicates that factor(s) other than urine Mg concentration are important in urethral obstruction. Cats with urethral obstruction due to naturally occurring disease, feline urological syndrome (FUS), had markedly lower urine Mg concentrations than cats fed high Mg diets. This finding refutes the theory that cats develop FUS because of primary Mg hyperabsorptive phenomena or because of a primary urinary leak of Mg. It also indicates that factors other than urine Mg concentration are involved in the genesis of naturally occurring urethral obstruction. Another difference between the natural and the induced disease was related to the character of the urinary precipitates. Experimental diets higher in Mg concentration caused urolith formation, which is uncommon with FUS. Lower Mg diets caused obstruction with aggregates of crystals, but mucus was not observed. However, in the experimental disease induced in the present study, urinary precipitates were predominantly or exclusively struvite, as has been reported in the natural disease. Many similarities were seen between the diet-induced disease and FUS, but factors in addition to Mg intake are involved in the natural disease. The importance of Mg, compared with the undefined factors, remains to be established.

Topics: Animals; Cat Diseases; Cats; Food, Fortified; Hematuria; Magnesium; Magnesium Compounds; Magnesium Oxide; Male; Minerals; Phosphates; Struvite; Syndrome; Urethral Obstruction; Urination Disorders

Topics: Animals; Calcium Oxalate; Calcium Phosphates; Cat Diseases; Cats; Female; Magnesium; Magnesium Compounds; Male; Minerals; Phosphates; Sex Factors; Species Specificity; Struvite; Urethral Diseases; Urinary Calculi

Topics: Animal Feed; Animals; Cat Diseases; Cats; Diet; Energy Intake; Intestinal Absorption; Kidney; Magnesium; Magnesium Compounds; Male; Phosphates; Struvite; Urethral Obstruction

Twenty-four cats were fed a dry commercial cat food once daily for 2 weeks and then ad libitum for 2 weeks. Urine pH was measured 4 times daily the last 3 days of each feeding period. Subsequently, the cats were allotted to 2 equal groups and fed ad libitum an experimental, dry ration with or without 1.5% ammonium chloride for 11 months. During this period, urine pH was measured at 1, 3, 6, and 9 weeks, then monthly through 29 weeks, and then every 6 weeks for the duration of the study. When the cats were fed ad libitum, urine pH remained constant throughout the day, regardless of ration. In cats fed once daily, urine pH increased to 7.6 by 2 hours after feeding and remained between 6.6 and 7.6 for 9 hours. Urine pH remained constant throughout the study when cats were fed the experimental ration with or without 1.5% ammonium chloride, but was significantly different (P less than 0.01) between the 2 groups, 5.9 +/- 0.3 (n = 1,035) and 7.0 +/- 0.5 (n = 616), respectively. Ammonium chloride consumption had no effect on food and water consumption or body weight. It was concluded that ammonium chloride was an effective urinary acidifier for a prolonged time, maintained urine pH below 6.6, and did not decrease food intake when given at a concentration of 1.5% of the diet.

Topics: Ammonium Chloride; Animals; Cat Diseases; Cats; Diet; Evaluation Studies as Topic; Hydrogen-Ion Concentration; Magnesium; Magnesium Compounds; Male; Phosphates; Struvite; Urinary Calculi; Urine

Two groups of 12 cats were fed ad libitum an experimental dry expanded ration high in magnesium (0.37%, dry matter basis) and similar to most commercial dry cat foods in all other nutrients. The diet of one of the groups contained 1.5% ammonium chloride, which was added to the diet before processing. Urethral obstruction developed twice in 7 of the 12 cats fed the ration without ammonium chloride. Of the 5 remaining cats in that group, 2 had calculi in the urinary bladder and urethra at necropsy. In contrast, only 2 of the 12 cats fed the ration containing ammonium chloride had urethral blockage once; neither cat had another blockage. Both cats had been catheterized twice as paired controls before urethral obstruction. One of these 2 cats died from a urinary tract infection apparently introduced through the indwelling catheter, and at necropsy there were 2 small calculi in the urethra. At the end of the study, only 1 other cat fed the ammonium chloride diet had a calculus in the urinary bladder at necropsy; this cat had not had a urethral obstruction throughout the study. After each cat had 2 urethral blockages, its diet was changed. Four cats were fed the ration containing ammonium chloride and 3, a dry, commercial ration. Of the 4 cats fed the diet containing ammonium chloride, none developed another urethral obstruction within 6 months, and at necropsy, no calculi were in the urinary bladder or urethra. Two of the 3 cats fed the commercial ration experienced urethral blockage within 3 months. These 2 cats were then fed the diet containing ammonium chloride.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Ammonium Chloride; Animal Feed; Animals; Cat Diseases; Cats; Hydrogen-Ion Concentration; Magnesium; Magnesium Compounds; Male; Phosphates; Struvite; Urethral Obstruction; Urinary Calculi; Urine