Struvite Crystalluria Research Articles

Urolithiasis: Review and case description of a Wagyu feeder steer with struvite crystalluria and urolithiasis treated with calcium boluses

Bovine urolithiasis, or formation of calculi in the urinary tract of cattle due to struvite crystalluria, is a life-threatening and painful disease. Clinical signs often go unnoticed until the prognosis of the animal is poor and immediate euthanasia is necessary. The author reports a treatment used to disrupt the disease process. The treatment allowed a valuable beef animal to comfortably complete its finishing stage without using medications that require a withdrawal period prior to harvest. A 27-month-old Wagyu steer in the finishing phase presented with inappetence, polyuria, dysuria and depression. Urinalysis showed an abundance of struvite crystals. Serum chemistry revealed a calcium:phosphorus ratio of 1.2:1. To avoid early harvest and progression of the disease, the steer was treated with over-the-counter calcium boluses, which were successful in dissolving the crystals. Daily urinalysis was used to determinethe frequency of treatment needed. The author proposes an alternative method for treating struvite crystalluria and preventing subsequent urolithiasis in feeder steers.

Ultrasound diagnosis and medical management of presumed segmental ureteritis in a cat

AbstractThis case report describes successful medical management of presumed segmental ureteritis in a 10‐year‐old, male, neutered, domestic shorthair cat. The cat presented for acute onset of lethargy, weight loss and a heart murmur. Abdominal palpation revealed renal asymmetry. Urinalysis and culture identified haematuria, struvite crystalluria and Proteus mirabilis infection. Abdominal ultrasound showed right hydronephrosis, right hydroureter and a focal right ureteral mass. Successful resolution of the right hydronephrosis, hydroureter and ureteral mass was achieved with antimicrobial therapy alone. Medical management may be an alternative, less invasive treatment to surgery for presumed feline segmental ureteritis.

Therapeutic Effects of Parenteral Vitamin C (Ascorbic Acid) on Struvite Crystalluria in Domestic Male Cats

BACKGROUND: Struvite crystals (Magnesium Ammonium Phosphate) are one of the most common causes of urolith formation in cats. Presence of these crystals in urea leads to urinary obstruction and idiopathic cystitis. The prevalence of urinary crystals has increased in recent years, thus there has been a growing interest in development of noninvasive, fast responsive therapies. Vitamin C is a safe compound with antioxidant properties. This vitamin is known as urine acidifier as well. Since struvite crystals are more soluble in acidic pH, it could be expected that vitamin C application could improve crystals dissolution as well as their disposal. It could also prevent other complications. OBJECTIVES: This study was designed to analyze the effects of vitamin C in reducing the rate and intensity of struvite crystals with current long term therapies such as diet alteration, acidifier’s applications and diuretics. METHODS: Ten male domestic cats with clinical signs of lower urinary tract disease were selected. Struvite crystalluria was confirmed by urine analysis and ultrasonography. Cats were divided to treatment and control groups each containing 5 cats. Both groups were treated by conventional therapies for two weeks, however, during the 1st week the treatment group received injectable vitamin C (100 mg/kg, every 24h, SC) and the control group received oral DL Methionine (200mg/cat, every 8h), in addition to conventional therapies. Urine was collected at days 0, 7 and 14 and its pH, specific gravity and number of crystals were calculated. Presence of floating echogenic foci was evaluated using ultrasound. RESULTS: Significant decrease in struvite crystalluria was observed in both groups. However, in group treated by vitamin C this decrease was faster and more effective. In addition, in case of obstruction, vitamin C showed better therapeutic effects. CONCLUSIONS: According to these results, vitamin C injection could be a therapeutic approach in treatment of urinary tract obstructions where fast response is needed to avoid further complications. Oral methionine seems to be a suitable choice for prophylaxis in patients with moderated signs and relatively high urine pH or continuing therapy to prevent recurrence of disease.

Clinical description of Corynebacterium urealyticum urinary tract infections in 11 dogs and 10 cats

To examine the clinical signs, laboratory findings, possible predisposing factors, antimicrobial sensitivity and outcomes of dogs and cats diagnosed with urinary tract infection caused by Corynebacterium urealyticum. Retrospective, observational study of dogs and cats that were diagnosed with urinary tract infection caused by C. urealyticum. This report concerns a total of 11 dogs and 10 cats. All cats had a history of urethral catheterisation, and six cats had undergone urological surgery before diagnosis of this specific infection. Dogs had history of neurogenic urinary incontinence (n=5), urethral catheterisation (n=4), urological surgery (n=4), lower urinary tract disease (n=2) or prostatic disease (n=1). In seven animals, previous urine culture was negative. Median urine pH was 8.6 (interquartile range 7.5 to 9), and 19 animals had pyuria and struvite crystalluria. Encrusted cystitis was diagnosed by abdominal ultrasound in nine animals. All but one isolate were resistant to at least three antimicrobial classes. Thirteen isolates were sensitive to tetracyclines. There was bacterial and clinical resolution of the infection in nine dogs and seven cats. Two animals died from sepsis and two cats were euthanased because of clinical deterioration. Urinary tract infection caused by C. urealyticum should be suspected in animals with pre-existing urinary disorders, especially if urine is alkaline and there is struvite crystalluria, negative routine urine culture and encrusted cystitis.

Factors associated with hematuric struvite crystalluria in cats

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.

Risk factors and clinical presentation of cats with feline idiopathic cystitis

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.

Renal transplantation in cats with calcium oxalate urolithiasis: 19 cases (1997–2004)

To determine outcome of renal transplantation in cats with renal failure associated with calcium oxalate urolithiasis. Retrospective case series. 19 cats. Medical records were reviewed for evaluation of signalment, preoperative clinical signs, physical examination results, dietary history, clinicopathologic data, abdominal imaging, postoperative diet, complications, and long-term outcome. The domestic shorthair was the most common breed represented. There were 13 spayed females and 7 castrated males. Mean age was 6.8 years. Clinical signs included weight loss, lethargy, vomiting, anorexia, polyuria, and polydipsia. Before surgery, cats received commercially available canned or dry food (n = 10), a prescription renal failure diet (5), a commercial diet to manage struvite crystalluria (1), or an unknown diet (3). Seventeen cats were anemic. All cats were azotemic. Hypercalcemia was detected in 7 cats. Abdominal imaging revealed nephrolithiasis, ureterolithiasis, or both in all cats. Median duration of survival of all cats was 605 days. Eight cats were alive 282 to 2,005 days (median, 1,305 days) after surgery. Eleven cats died 2 to 1,197 days (median, 300 days) after surgery. Five cats formed calculi in their allograft (120 to 665 days). Two of the 5 cats that formed calculi were hypercalcemic. Four of the 5 cats died following complications associated with formation of calculi. Renal transplantation appears to be a viable option for cats in renal failure secondary to calcium oxalate urolithiasis. In addition to reported complications in renal transplant recipients, formation of calculi within the allograft may also occur.

Effects of choreito consumption on urine variables of healthy cats fed a magnesium-supplemented commercial diet

Abstract Objective To investigate the effect of choreito consumption (500 mg/kg of body weight/d) on struvite crystal formation and signs of lower urinary tract disease (LUTD) in cats consuming a commercial canned diet with 0.5% added inorganic magnesium. Sample Population 6 male and 6 female adult cats, all considered to be clinically normal on the basis of physical examination findings; results of CBC, serum biochemical analyses, urinalyses, and urine cultures; and freedom from urolithiasis on the basis of urethrocystoscopic (females) or urethrocystographic (males) findings. Procedure Diets were fed for 12 weeks, or until appearance of signs of LUTD, including dysuria, hematuria, urine pH > 7.0, and severe struvite crystalluria. Presence of at least 2 of these signs was required for removal from study. Urine specimens were examined for electrolytes, struvite crystal content, and hematuria. Results Results for urine variables were compared between groups at 4 weeks, because of reduction in cat numbers attributable to removal from study. Struvite crystal content of 24-hour urine specimens was significantly lower for cats fed the choreito-containing diet. Moreover, frequency and severity of hematuria were significantly decreased in cats fed the choreito-containing diet. Correlation between hematuria and struvite crystal content was not observed in either group. Additionally, all 6 cats fed the diet without choreito had been removed from study by day 58 because of signs of LUTD. Of the 6 cats fed the choreito-containing diet, 2 completed the 12-week study. Clinical Relevance Choreito may be beneficial for relief of some signs of struvite-associated LUTD disease in cats. (Am J Vet Res 1997;58:146–149)

Dietary treatment of progressive feline struvite crystalluria

ABSTRACTEight cats were fed a dry commercial cat food and after six months developed urinary struvite crystalluria with alkaline urine. The animals were subsequently divided into two groups and fed either a dry or a canned struvite calculolytic diet. The crystalluria was reduced after five to six weeks with both treatment diets. Decreased crystalluria coincided with a reduction in urinary pH and an increased titratable acidity. The highest food acid load, determined by the lowest undetermined anion, was found with the dry diet and resulted in the highest renal hydrogen excretion, measured as net acid excretion.

Effect of dietary phosphoric acid supplementation on acid-base balance and mineral and bone metabolism in adult cats

Summary Experimental evidence indicates that maintenance of urinary pH ≤ 6.4 is the single most effective means of preventing feline struvite crystalluria or urolithiasis of noninfectious causes. This may be accomplished by dietary acidification, but must be moderated to avoid potential adverse effects of excessive acidification, including bone demineralization, negative calcium balance, potassium depletion, and renal disease. Effects of chronic dietary phosphoric acid supplementation on acid-base balance and on mineral and bone metabolism were investigated in adult, domestic cats. One group of 6 cats was fed a basal, naturally acidifying diet without added acidifiers, and another group of 6 cats was fed 1.7% dietary phosphoric acid. Changes observed during 12 months of study included development of noncompensated metabolic acidosis, increased urinary calcium excretion, and lower but positive calcium balance in cats of both groups. Urinary pH decreased in cats of both groups, but was significantly (P < 0.05) and consistently maintained ≤ 6.4 in cats given dietary phosphoric acid. Urinary phosphorus excretion increased in cats of both groups, but was significantly (P < 0.05) greater in phosphoric acid-supplemented cats, leading to lower overall phosphorus balance as well. Potassium balance decreased in cats of both groups, but was only transiently negative in the phosphoric acid-supplemented cats midway through the study, and normalized at positive values thereafter. Plasma taurine concentration was not affected by dietary acidification, and remained well within the acceptable reference range for taurine metabolism. Double labeling of bone in vivo with fluorescent markers was followed by bone biopsy and histomorphometric measurement of several static and dynamic variables of bone formation. Overall indices of bone formation decreased in cats of both groups with age and confinement, but were not affected by dietary phosphoric acid supplementation. Dietary supplementation with phosphoric acid used as the principal inorganic P source to achieve moderate and stable degree of urinary acidification, did not appear over the course of 1 year, to have induced adverse effects on mineral, bone, or taurine balance in these adult domestic cats.

Medical dissolution of feline struvite urocystoliths

Summary The efficacy of a diet designed to facilitate dissolution of feline magnesium ammonium phosphate (struvite) uroliths was evaluated in 30 cases of urocystoliths, involving 27 cats. The number of urocystoliths per cat varied from 1 to 5. In 20 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.

Feline struvite crystalluria: A comparison of some commercially available dry cat diets in New Zealand

Thirteen adult cats were each fed consecutively five test diets: firstly a complete canned diet, and then four commercially available dry cat diets (New Formula Biscats, Cat Chow, Go-Cat and Whiskettes) for 7,13, 5, 4 and 4 weeks respectively. Urine samples were tested for pH and presence of struvite crystals. Body weight was recorded weekly. Urine pH was ranked from acid to alkaline as follows: Whiskettes (pH 5.8), canned diet (pH 5.9), Biscats (pH 6.1), Cat Chow (pH 6.45) and Go-Cat (pH 6.5). The pH of urine when cats were fed Whiskettes, Biscats and canned diet was not significantly different. Biscats produced a urine pH significantly higher than Whiskettes but, in each case, these three diets produced a significantly lower urine pH than Cat Chow and Go-Cat. Struvite crystals occurred spontaneously in 9% of urine samples from cats when fed Whiskettes and Biscats, 71% when fed Cat Chow and 38% when fed Go-Cat: spontaneous struvite was not seen in any cat fed CX9. Haematuria was seen in 2.9% (2/69) urine samples from cats fed Cat Chow. One tom cat had a blocked urethra after 24 days on Go-Cat. No abnormalities were observed in any cat when fed canned diet, Biscats or Whiskettes. It was concluded that of the four dry cat diets tested only Biscats and Whiskettes produce urine with an acceptably low rate of spontaneous struvite crystalluria.

Feline struvite urolithiasis: fasting reduced the effectiveness of a urinary acidifier (ammonium chloride) and increased the intake of a low magnesium diet.

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)

Food intake and struvite crystalluria in ferrets.

Four adult, castrated, male ferrets were studied in two similar trials for effects of food intake on variables hypothesized to promote struvite (ammonium, magnesium, phosphate hexahydrate) crystal formation in urine. Struvite crystalluria occurred in three of the four ferrets. Urine pH (UpH) averaged 6.6 for these ferrets. UpH in the ferret without crystalluria was 6.0. By simple linear regression analysis, no relationship was found between the amount of food ingested and the urinary concentration and excretion of magnesium and phosphorous. However, urine osmolality and excretion of both protein and ammonium were correlated to food intake (P less than .05). Ways in which these effects could promote struvite crystal formation are discussed.