Dissolution Of Uroliths Research Articles

Medical dissolution of presumptive upper urinary tract struvite uroliths in 6 dogs (2012-2018).

Minimally invasive approaches are the standard for treatment of upper urinary tract uroliths in humans. To describe the medical dissolution of upper urinary tract uroliths in a series of dogs and report clinical outcomes. 6 female dogs (9 kidneys). Retrospective case series. A review of medical records in dogs that underwent medical dissolution of upper urinary tract uroliths utilizing diet, administration of antibiotics, and double-pigtail ureteral stent(s) placement, when indicated, was performed. Medical management was generally continued for 4 weeks beyond urolith dissolution. Information on biochemical, microbiological, imaging, and clinical outcomes before and after dissolution were recorded. Six dogs (9 kidneys) were included with bilateral (3) or unilateral (3) nephrolithiasis, ureterolithiasis, or a combination. A ureteral stent(s) was placed endoscopically in 5/6 dogs (6/9 kidneys) for obstructive ureterolithiasis (n = 5) or a nonobstructive massive nephrolith (n = 1). All dogs had a positive urine culture of Staphylococcus pseudintermedius with a median urine pH of 7.25 (range, 6.5-8) and 4/5 had pyonephrosis. All dogs had initial evidence of urolith dissolution at a median of 1.1 months (range, 0.42-5.9), with complete dissolution of ureteroliths at a median of 3.9 months (range, 1.5-7.6), nephroliths at 5.3 months (range, 1.5-7.6), and lower urinary tract uroliths at 0.87 months (range, 0.42-5.9). Stents were removed in 3/6 once dissolution was documented. The median follow-up time was 519 days (range, 177-2492 days). Medical dissolution and decompression of upper urinary tract struvite uroliths should be considered a minimally invasive treatment for dogs before more invasive options.

Effect of D,L methionine and ammonium chloride on urine acidification, urinary fractional excretion of calcium, and blood bicarbonate in clinically healthy goats.

Urinary acidification with ammonium chloride (AC) for urolith dissolution is a common treatment for goats with urolithiasis. Studies have reported increased fractional excretion of calcium (FECa) following AC administration, which could increase calcium-based urolithiasis. D,L methionine (MET) may result in similar acidification with less calcium excretion. To compare the effects of orally administered MET and AC on urine and blood pH, FECa, and blood HCO3- concentrations in male goats. Prospective, randomized, crossover study. 12 healthy, 5-to-6-month-old Boer-cross wethers were administered 200 mg/kg of AC or MET orally for 14 days with a 7-day washout period between trials. Venous blood and urine samples were collected every 2 days. The effects of treatment and treatment day on urine and blood pH, HCO3-, and FECa were assessed using linear mixed models. Ammonium chloride and MET lowered least squares means (LSM) urine pH on day 6 (LSM, 7.49; 95% CI, 6.44 to 8.54), 8 (LSM, 7.78; 95% CI, 6.73 to 8.83), and 10 (LSM, 7.53; 95% CI, 6.49 to 8.58) when compared to day 0 (LSM, 8.23; 95% CI, 7.18 to 9.28). Some goats' urine indicated acidification (pH < 7.0) in the first phase of the trial; however, for the entire trial, a significant treatment effect was not detected on urine pH, blood pH, blood HCO3- or log10 FECa. Ammonium chloride and MET acidified urine of some goats. Dietary cation-anion difference should be considered when treating healthy goats to acidify their urine.

D,l-Methionine in combination with amoxicillin-clavulanic acid successfully dissolves spontaneously occurring infection-induced struvite urocystoliths in dogs: a pilot study.

To determine the efficacy and safety of a urinary acidifier (d,l-methionine [Methio-Form]) and an antimicrobial agent (amoxicillin-clavulanic acid [Clavamox]) without changing diet for dissolving infection-induced struvite urocystoliths in dogs. 14 dogs were recruited for this prospective study; 11 completed it and 3 dogs withdrew due to inability of the owners to administer the treatment (n = 2) or refusal of treatment by the dog (1). All dogs were administered d,l-methionine (approx initial dose of 75 mg/kg, PO, q 12 h) and amoxicillin-clavulanic acid (22 mg/kg, PO, q 12 h) based on urine culture and sensitivity. Urine pH, urinalysis, urine culture, venous blood gas and serum biochemical analysis, and lateral survey abdominal radiographic images were evaluated initially and every 4 weeks until urolith dissolution (success) or lack of change in size and/or shape of urocystoliths on 2 consecutive reevaluation points (failure) occurred. Uroliths dissolved in 8 of 11 dogs in a median of 2 months (range, 1 to 4 months) with a final effective dosage of d,l-methionine of approximately 100 mg/kg, PO, every 12 hours. In 3 dogs, uroliths failed to dissolve and were removed surgically; they contained variable amounts of calcium oxalate. No adverse events occurred. Infection-induced struvite urolithiasis is 1 of the 2 most common minerals occurring in canine uroliths. Results of this study supported the use of d,l-methionine and amoxicillin-clavulanic acid without changing diet for dissolution of infection-induced struvite urocystoliths in dogs.

Retrospective analysis of 131 feline uroliths from the Republic of Ireland and Northern Ireland (2010-2020)

BackgroundThe proportions of different urolith types have not been investigated in cats from the Republic of Ireland (ROI) and Northern Ireland (NI) previously. The objective of this study was to investigate the proportions of different feline urolith types submitted to Minnesota Urolith Center from the ROI and NI from 2010 to 2020. An additional aim of this study was to identify potential risk factors associated with each urolith type in cats in this geographic area.ResultsOne hundred and thirty-one uroliths were submitted for the studied period with 44.3% being struvite, 43.5% calcium oxalate and 7.6% compound. Only 11 uroliths were submitted in the first 4 years. The number of submissions increased after 2015, peaking in 2019 with 25 submissions. Due to low numbers no conclusions could be made about changes in incidence of urolith types over time. Cats ≤7 years of age were significantly more likely to be diagnosed with struvite uroliths (OR, 2.87 [1.37-6.06]; p = 0.007) while cats ≥7 years of age with calcium oxalate uroliths (OR, 2.67, [1.29-5.37], p = 0.004).ConclusionsThis is the first epidemiologic study of urolithiasis from cats in the ROI and NI. The most prevalent types of uroliths in our study population were struvite and calcium oxalate. Due to the low number of urolith submissions, changes in the incidence of different uroliths could not be accurately determined. Increasing age was associated with calcium oxalate formation while younger cats were more commonly diagnosed with struvite urolithiasis which can be medically dissolved. Therefore, urolith dissolution is more likely to be successful in young cats than older cats.

International Society for Companion Animal Infectious Diseases (ISCAID) guidelines for the diagnosis and management of bacterial urinary tract infections in dogs and cats

Urinary tract disease is a common clinical presentation in dogs and cats, and a common reason for antimicrobial prescription. This document is a revision and expansion on the 2011 Antimicrobial Use Guidelines for Treatment of Urinary Tract Disease in Dogs and Cats, providing recommendations for diagnosis and management of sporadic bacterial cystitis, recurrent bacterial cystitis, pyelonephritis, bacterial prostatitis, and subclinical bacteriuria. Issues pertaining to urinary catheters, medical dissolution of uroliths and prophylaxis for urological procedures are also addressed.

Effects of two calculolytic diets on parameters of feline mineral metabolism.

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).

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

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.

Diagnosis, Medical Treatment, and Prognosis of Feline Urolithiasis

Radiographic or ultrasonographic evaluation of the urinary tract is required to consistently detect feline uroliths. Evaluation of clinical, laboratory, and radiographic findings facilitate "guesstimation" of the mineral composition of uroliths. Therapy should not be initiated before appropriate samples have been collected for diagnosis. The objectives of medical management of uroliths are to arrest further growth and to promote urolith dissolution by correcting or controlling underlying abnormalities. For therapy to be effective, it must induce undersaturation of urine with calculogenic crystalloids by (1) increasing the solubility of crystalloids in urine, (2) increasing the volume of urine in which crystalloids are dissolved or suspended, and (3) reducing the quantity of calculogenic crystalloids in urine.

Canine cystinuria: An extended study on the effects of 2-mercaptopropionylglycine on cystine urolithiasis and urinary cystine excretion

A clinical study covering 1 to 6 years was undertaken during which 25 cystinuric dogs were orally treated with 2-mercaptopropionylglycine (2-MPG). The drug was effective at dissolving uroliths at a dose of approximately 40 mg kg-1 body weight. In 15 dogs with bladder uroliths, complete urolith dissolution was achieved on 9/17 occasions (53%). When 2-MPG was administered prophylactically at 30 mg/kg body weight, uroliths did not reform in 14 dogs (56%). In four dogs, uroliths re-formed during treatment, but dissolved when the dose of 2-MPG was raised to 40 mg kg-1 body weight. Six dogs were surgically treated, and in two of these animals the uroliths were found to consist of magnesium ammonium phosphate. Euthanasia was performed on six dogs during the study; three because of recurrent uroliths with urethral obstruction, and three because of aging. In one dog, uroliths were present in the bladder throughout the study. The purpose of the study was to propose a new strategy for individual treatment of cystinuric dogs. This was accomplished by measuring the urinary free cystine concentration and the mixed cysteine-2-MPG disulphide in a subgroup of 15 of the 25 dogs. To evaluate cystine excretion, morning samples of urine were used, and the cystine concentration was related to the creatinine concentration. For dose adjustment it was difficult to evaluate the effect of 2-MPG on urinary cystine excretion, especially when cystine uroliths were present. However, this variable was studied in order to identify dogs with a strong tendency for urolith formation during 2-MPG treatment. In some cases, urinary cystine excretion returned to normal with time, and in three dogs, 2-MPG treatment could be stopped after 1.5 to 3.5 years. In spite of no further treatment, urinary cystine was almost undetectable up to 2 years later, and the dogs did not develop any new uroliths. It was concluded that 2-MPG is a satisfactory alternative treatment for cystinuric dogs. It has a good prophylactic effect, shown as a change in the rate of urolith formation from on average 6 months before to 17 months during 2-MPT treatment. The drug was shown to have few side effects, and the dog owner drug compliance can be followed by measurement of the mixed 2-MPG-cysteine disulphide.

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.

Medical Dissolution of Canine Struvite Uroliths

Medical therapy is an effective method of canine struvite urolith dissolution. Recommendations include (1) eradication or control of urinary tract infection (if present), (2) use of calculolytic diets, and (3) administration of urease inhibitors to patients with persistent urinary tract infection caused by urease-producing microbes.

Medical Management of Male and Female Cats with Nonobstructive Lower Urinary Tract Disease

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.