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- Author or Editor: John M. Kruger x
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Abstract
OBJECTIVE
To determine if urine electrolyte assessments can be used to monitor the adequacy of mineralocorticoid therapy in dogs with hypoadrenocorticism (HA).
ANIMALS
29 dogs with naturally occurring glucocorticoid- and mineralocorticoid-deficient HA.
PROCEDURES
Urine sodium and potassium concentrations, sodium-to-potassium ratios, sodium-to-creatinine ratios, and potassium-to-creatinine (K:Cr) ratios were evaluated in dogs with newly diagnosed HA that were treated with desoxycorticosterone pivalate (DOCP). Dogs underwent measurements of urine and serum sodium, potassium, and creatinine concentrations and plasma renin activities twice monthly for up to 3 months. Regression analyses and calculation of coefficients of determination (R 2) were performed to investigate potential associations between urine and serum variables. Urine variables also were compared between dogs considered to be undertreated or overtreated based on plasma renin activities.
RESULTS
Urine K:Cr ratios were significantly associated with serum potassium concentrations 10 to 14 days (P = .002) and 30 days (P = .027) after the initial DOCP injection, but R 2 values were only 0.35 and 0.17, respectively. Urine K:Cr ratios (median [IQR]) also were higher in dogs that were overtreated with DOCP (1.3 [0.7 to 2.3]) as compared to those dogs that were undertreated with DOCP (0.8 [0.5 to 0.9]) at 10 to 14 days after the initial DOCP injection (P = .039) but not at 30 days after the initial injection. Other urine variables were not significantly different between undertreated and overtreated dogs.
CLINICAL RELEVANCE
Measures of urine electrolytes were not useful for assessing the adequacy of mineralocorticoid therapy in HA dogs that were treated with DOCP.
Abstract
Objective—To determine whether short-term amitriptyline administration would be efficacious in the treatment of acute, nonobstructive, idiopathic lower urinary tract disease in cats.
Design—Randomized controlled trial.
Animals—31 untreated male and female cats with acute, nonobstructive, idiopathic lower urinary tract disease.
Procedures—Cats were treated with amitriptyline (5 mg/d; n = 16) or a placebo (15) for 7 days and monitored for pollakiuria, hematuria, and adverse events. Cats were reexamined 1 month after treatment, and owners were interviewed by telephone 6, 12, and 24 months after treatment.
Results—2 amitriptyline-treated cats were excluded from analyses because of acquired urinary tract infection. Clinical signs resolved by day 8 in 8 amitriptylinetreated and 10 control cats. There were no apparent differences in likelihood or rate of recovery from pollakiuria or hematuria between groups. Overall, clinical signs recurred significantly faster and more frequently in amitriptyline-treated than control cats. However, after excluding recurrences within 21 days of treatment, risk of recurrence was similar in both groups. Increasing age was significantly associated with increased likelihood and rate of recovery from hematuria and with decreased risk of recurrence of signs.
Conclusions and Clinical Relevance—Results suggest that short-term amitriptyline treatment has no benefit in terms of resolution of pollakiuria and hematuria in cats with idiopathic lower urinary tract disease and may be associated with an increased risk of recurrence. (J Am Vet Med Assoc 2003:222:749–758)
Abstract
Objective—To assess antimicrobial resistance among bacteria isolated from dogs and cats admitted to a veterinary teaching hospital (VTH), determine the incidence of acquisition of and frequency of persistent colonization by antimicrobial-resistant organisms among these animals, and identify risk factors associated with these variables.
Design—Prospective longitudinal study.
Animals—622 dogs and 92 cats admitted to a VTH and expected to stay ≥ 48 hours.
Procedures—Samples were collected with rectal and nasal or oropharyngeal swabs at admission and discharge. Isolates of enterococci, staphylococci, and Escherichia coli were tested for antimicrobial resistance via microbroth dilution methods. A subset of isolates was analyzed with pulsed-field gel electrophoresis and multilocus sequence typing. Significant trends in proportions of organisms with antimicrobial resistance over the 3-year study period were assessed.
Results—The proportion of staphylococci with antimicrobial resistance increased, whereas the proportion of E coli with resistance decreased, over time; resistance among enterococci was more variable. For 506 dogs with paired admission and discharge samples, multidrug-resistant (MDR) E coli was acquired by 40 (8%) and methicillin-resistant Staphylococcus aureus (MRSA) was acquired by 7 (1.4%); hospitalization for > 3 days was significantly associated with both variables. Most (5/7 isolates) acquired MRSA was of sequence type (ST) 5.
Conclusions and Clinical Relevance—Extended hospitalization was associated with increased risk of acquiring MDR E coli or MRSA, although few animals acquired MRSA. It is unclear whether associations were confounded by illness severity or use of infection control measures. Additionally, MRSA of ST5, which has been associated with small animal medicine, was the most commonly acquired MRSA in this study.
Abstract
Objective—To evaluate the effect of nutrition on recurrent clinical signs of lower urinary tract (LUT) disease in cats with idiopathic cystitis.
Design—Randomized, controlled, masked clinical trial.
Animals—31 cats with acute nonobstructive idiopathic cystitis.
Procedures—Cats were assigned to receive 1 of 2 foods (a cystitis prevention or control food) that differed in mineral (calcium, phosphorous, and magnesium), antioxidant, and fatty acid profiles. Owners documented LUT signs daily for up to 1 year. The primary endpoint was the number of recurrent episodes in which a cat had multiple (≥ 2 concurrent) LUT signs within a day (defined as multiple-sign day). Consecutive days in which a cat had multiple LUT signs were considered as a single episode.
Results—4 cats fed prevention food and 2 cats fed control food were excluded from analysis because of noncompliance, gastrointestinal signs, food refusal, or owner voluntary withdrawal. The proportion of cats fed prevention food that had ≥ 1 recurrent episode of multiple-sign days (4/11) was not significantly lower than that of cats fed control food (9/14). However, cats fed prevention food had significantly lower mean incidence rates for recurrent episodes of multiple-sign days (0.7 episodes/1,000 cat-days) and episodes of hematuria (0.3 episodes/1,000 cat-days), dysuria (0.2 episodes/1,000 cat-days), and stranguria (0.2 episodes/1,000 cat-days) as single LUT signs, compared with cats fed control food (5.4, 3.4, 3.1, and 3.8 episodes/1,000 cat-days, respectively). Significantly fewer cats fed prevention food required analgesics (4/11), compared with cats fed control food (12/14).
Conclusions and Clinical Relevance—Foods with differing nutritional profiles appeared to impact mean incidence rates of recurrent feline idiopathic cystitis-associated signs.
Abstract
Objective—To compare accuracy of estimates of cystolith size obtained by means of plain radiography, double-contrast cystography, ultrasonography, and computed tomography.
Sample Population—30 canine cystoliths ranging from 1 to 11 mm in diameter with various mineral compositions.
Procedures—A bladder phantom model was created by filling a rubber balloon with saline (1% NaCl) solution and positioning it on top of a 2% gelatin cushion at the bottom of a water-filled 4-quart container. Cystoliths were individually placed in the bladder phantom and imaged by each of the 4 techniques. For each image, cystolith size was measured by 2 radiologists with computerized calipers, and size estimates were compared with actual cystolith size.
Results—Mean cystolith size estimates obtained by means of radiography, cystography, and computed tomography did not differ significantly from each other. However, for ultrasonographic images, mean ± SD difference between actual and estimated cystolith size (2.95 ± 0.73 mm) was significantly higher than mean difference for radiographic, cystographic, and computed tomographic images. For ultrasonography, mean ± SD percentage overestimation in cystolith size was 68.4 ± 51.5%.
Conclusions and Clinical Relevance—Results indicated that measurements of cystolith size obtained by means of ultrasonography may overestimate the true size. This suggests that cystolith size estimates obtained by means of ultrasonography should be interpreted with caution whenever cystolith size may influence patient management.
Abstract
Objective—To compare the findings of light microscopic evaluation of routine unstained wet-mounted preparations and air-dried, modified Wright-stained preparations of urine sediment with results of quantitative aerobic bacteriologic culture of urine.
Design—Masked prospective study.
Sample Population—459 urine samples collected by cystocentesis from 441 dogs.
Procedure—Urinalyses and quantitative bacteriologic cultures of urine were performed. Unstained wetmounted preparations and air-dried, modified Wrightstained urine sediment preparations were examined by light microscopy for the presence of bacteria.
Results—Compared with results of quantitative bacteriologic culture, routine unstained preparations and modified Wright-stained preparations had sensitivities of 82.4% and 93.2%, specificities of 76.4% and 99.0%, positive predictive values of 40.1% and 94.5%, negative predictive values of 95.8% and 98.7%, and test efficiencies of 77.3% and 98.0%, respectively. Compared with 74 samples that yielded growth on bacteriologic culture, the routine unstained method had concordance and misclassification rates of 39.2% and 60.8%, respectively, whereas the Wright-stained method had concordance and misclassification rates of 78.4% and 21.6%, respectively. Significant associations between each of occult blood in urine, pyuria, female sex, and lower urine specific gravity with bacteriuria detected by Wright-stained sediment examination and quantitative bacteriologic culture of urine were identified.
Conclusions and Clinical Relevance—Examination of modified Wright-stained preparations of urine sediment appeared to be a rapid, cost effective method that significantly improved the sensitivity, specificity, positive predictive value, and test efficiency of light microscopic detection of bacteriuria, compared with that of the routine unstained method. (J Am Vet Med Assoc 2004; 224:1282–1289)
Abstract
Objective—To compare 5 methods of preparation of RNA from feline urine samples for use in a feline calicivirus (FCV), p30 gene-based, real-time reverse-transcriptase polymerase chain reaction (RT-PCR) assay.
Sample Population—Urine and blood samples from 6 specific-pathogen-free cats.
Procedures—Aliquots of each urine sample (unmodified, centrifuged, or mixed with whole or hemolyzed blood) were spiked with FCV and serially diluted in urine. Serial dilutions of FCV in tissue culture medium were used as positive controls. Viral RNA was prepared via dilution and thermal inactivation (DT method), polyethylene glycol precipitation (PEG method), isolation with oligo(dT)25-coated magnetic beads (dTMB method), or extraction by use of 2 silica gel–based columns (RN or QA method). Lower detection limits and mean RT-PCR threshold cycle (Ct) values associated with each RNA preparation method and sample type were compared.
Results—Because DT-prepared samples yielded negative results via RT-PCR assay, this method was not evaluated. Lower detection limits (TCID50/sample) for the assay in urine were 1,950, 104, 11, and 7 for PEG-, dTMB-, RN-, and QA-prepared samples, respectively. For RN and QA preparations, Ct values were similar and significantly lower than those for dTMB and PEG preparations. Overall, urine modifications did not affect FCV RNA detection in dTMB-, QA-, and RN-prepared samples.
Conclusions and Clinical Relevance—Of the methods evaluated, the RN and QA methods of RNA preparation were most appropriate for the FCV RTPCR assay. An RT-PCR assay optimized for detection of FCV in feline urine may aid investigations of FCVinduced urinary tract diseases in cats. (Am J Vet Res 2005;66:915–920)
Abstract
Objective—To evaluate the effects of nephrotomy on renal function in clinically normal cats.
Animals—20 specific-pathogen-free, 9- to 11-month old female mixed-breed cats.
Procedure—Serum chemistry analyses, CBC determinations, urinalyses, microbiologic urine cultures, renal ultrasonography, abdominal radiography, and single-kidney and total glomerular filtration rate (GFR) determinations by use of renal scintigraphy and measurements of plasma disappearance of technetium 99m-diethylenetriaminepentaacetic acid were performed before surgery and at 3, 12, 26, 52, and 78 weeks after surgery in 10 cats that underwent unilateral nephrotomy and in 10 control cats that underwent a sham surgical procedure.
Results—Two cats (1 from each group) did not complete the study, and their data were eliminated from analyses. Unilateral nephrotomy resulted in a 10% to 20% reduction in mean single-kidney GFR, compared with that of nephrotomy contralateral control kidneys. However, mean total GFR in nephrotomy-group cats was not significantly different from that of shamgroup cats. Over the 78 weeks of study, mean total GFR declined 34% and 40% in nephrotomy- and sham-group cats, respectively. Adverse events associated with nephrotomy included persistent microscopic hematuria, renal pelvis hyperechogenicity with distant shadowing on ultrasonographic evaluation, dilatation of renal pelves, and hydronephrosis.
Conclusions and Clinical Relevance—Nephrotomy in normal functioning feline kidneys results in a modest relative reduction in renal function, compared with contralateral kidney controls, but has minimal effect on total GFR when compared with sham-operated control cats. However, any detrimental effects of nephrotomy may be magnified in cats with diseased kidneys, which may have little or no capacity for repair or compensation. (Am J Vet Res 2005;66:1400–1407)
Abstract
Objective—To compare the efficacy and safety of using 2 commercially available, low-magnesium, urine-acidifying dry foods to dissolve sterile struvite uroliths in cats.
Design—Prospective, multicenter, randomized clinical trial
Sample—37 cats with presumed struvite uroliths.
Procedures—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.
Results—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.
Conclusions and Clinical Relevance—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.
