International Renal Interest Society Research Articles

Assessment of individual kidney function in a dog with congenital anomalies of the urinary tract

A 21-month-old entire female labrador retriever was presented for polyuria, pollakiuria, haematuria and intermittent urinary incontinence. Clinical signs were absent during antibiotic treatment but reoccurred shortly after completion of a...

Frequency of bacteriuria in dogs with chronic kidney disease: A retrospective study of 201 cases.

BackgroundStudies have shown an increased prevalence of positive urine culture (PUC) in cats with chronic kidney disease (CKD); no information is available in dogs.ObjectivesTo document the PUC frequency in a cohort of dogs with CKD, determine risk factors for PUC, and identify associations between clinicopathologic data and PUC.AnimalsTwo hundred one client‐owned dogs with CKD.MethodsRetrospective, observational study. Dogs recruited from 2 veterinary teaching hospitals were included if they were diagnosed with CKD and had a culture performed on urine collected by cystocentesis. The PUC frequency was calculated, multivariate analysis was performed to identify risk factors, and associations with clinicopathologic data were investigated.ResultsSixty‐five dogs (32%) with CKD had PUC, including 8 (28%) in International Renal Interest Society (IRIS) stage 1; only 8% showed signs of a urinary tract infection. Escherichia coli was the most common isolate (67%). A PUC was more likely in females (odds ratio [OR], 3.22; 95% confidence interval [CI], 1.67‐6.37; P < .001) than males and in dogs with isosthenuria (OR, 2.48; 95% CI, 1.24‐5.03; P = .01) than in dogs with urine‐specific gravity 1.013‐1.024. A positive leukocyte esterase test and microorganisms found by urine sediment analysis were significantly associated with PUC (both P < .001).Conclusions and Clinical ImportanceDogs with CKD, even IRIS stage 1, have a high frequency of PUC and most cases are asymptomatic. A urine culture could be considered in the routine evaluation of dogs with CKD, but the clinical relevance of a PUC remains unknown and needs further evaluation.

Electrophoretic patterns of proteinuria in feline spontaneous chronic kidney disease.

The purpose of this study was to describe the electrophoretic patterns of proteinuria in cats at risk of and cats with chronic kidney disease (CKD), and to investigate whether the presence of high-molecular-weight (HMW) and low-molecular-weight (LMW) proteins were associated with CKD, proteinuria and/or disease progression. Healthy cats at risk of developing renal disease (n = 17) and cats affected with CKD at different stages (n = 22) were prospectively enrolled and sampled over time. Seventy urine samples were included and assayed with a commercially available sodium dodecyl sulfate-agarose gel electrophoresis (SDS-AGE) method. Each sample (gel lane) was inspected to identify albumin, HMW and LMW proteins, and an electrophoretic pattern (albuminuria, glomerular, tubular, mixed or negative) was assigned accordingly. Fisher's exact test was used to assess the distribution of HMW and LMW proteins in cats grouped according to International Renal Interest Society stage and to the magnitude of proteinuria, and to assess if HMW and LMW proteins at the time of inclusion were associated with the development and progression of CKD. In samples of cats at risk, the most common pattern was glomerular (84.6%); glomerular pattern was also common in cats with CKD (54.2%), although mixed proteinuria and tubular proteinuria were also present (29.5% and 11.4%, respectively). The presence of LMW proteins was associated with CKD (P <0.0001) and to a urine protein:creatinine ratio >0.2 (P = 0.025). Both HMW and LMW proteins were not associated with progression of CKD within 6 months (n = 14). Our results showed that HMW proteinuria is common in healthy cats at risk of developing CKD, although the pathological significance needs to be confirmed. The detection of LMW proteins in urine of cats suspected to be affected by CKD, especially in non-azotaemic, non-proteinuric or borderline proteinuric cats, suggests the presence of kidney damage.

Acute pancreatitis and acute kidney injury in dogs

Acute pancreatitis and acute kidney injury are well-documented comorbidities in human medicine. Dogs that develop acute kidney injury during hospitalization have significantly higher mortality rates than those that do not. The aim of this study was to evaluate the prevalence of acute kidney injury in dogs with acute pancreatitis and the prognostic value of various clinicopathological parameters. Cases of acute pancreatitis presented between January 2012 and June 2016 were identified. The diagnosis of acute pancreatitis was based on two or more of the following clinical signs: abdominal pain, diarrhea, vomiting or anorexia/hyporexia, no other abdominal extra-pancreatic diseases at abdominal ultrasound, and abnormal SNAP cPL test. Diagnosis of acute kidney injury was based on the guidelines of the International Renal Interest Society. Dogs were classified into survivors and non-survivors. Serum creatinine, urea, amylase, total calcium, total cholesterol, C-reactive protein, WBC and band neutrophils were evaluated at admission. Clinical severity index was calculated at admission. Clinical and clinicopathological data were compared between survivors and non-survivors.Sixty-five dogs with acute pancreatitis were assessed. Clinical severity index≥6.5 were associated with poor outcome (P=0.0011). Serum urea and creatinine concentrations at admission were significantly lower in survivors than non-survivors (P<0.0001 and P=0.0002, respectively). Acute kidney injury was diagnosed in 17/65 dogs (26.2%) and was associated with poor outcome (P<0.0001). Oligo-anuria was associated with poor outcome (P=0.0294). Increased clinical severity index and azotemia in dogs with acute pancreatitis were associated with an increased risk of mortality. Acute kidney injury may be a comorbidity of canine acute pancreatitis. The presence of oligo-anuria is associated with poor outcome.

The fecal microbiome and serum concentrations of indoxyl sulfate and p-cresol sulfate in cats with chronic kidney disease.

BackgroundIntestinal dysbiosis has been documented in humans with chronic kidney disease (CKD) and is thought to contribute to production of the uremic toxins indoxyl sulfate (IS) and p‐cresol sulfate (pCS). Characteristics of the fecal microbiome in cats with CKD and correlation to serum concentrations of uremic toxins are unknown.ObjectivesTo characterize the fecal microbiome and measure serum IS and pCS concentrations of cats with CKD in comparison to healthy older cats.AnimalsThirty client‐owned cats with CKD (International Renal Interest Society stages 2‐4) and 11 older (≥8 years) healthy control cats.MethodsProspective, cross‐sectional study. Fecal samples were analyzed by sequencing of 16S rRNA genes and Escherichia coli quantitative PCR (qPCR). Serum concentrations of IS and pCS measured using liquid chromatography tandem mass spectrometry.ResultsCats with CKD had significantly decreased fecal bacterial diversity and richness. Escherichia coli qPCR showed no significant difference in bacteria count between control and CKD cats. Cats with stage 2 (P = .01) and stages 3 and 4 (P = .0006) CKD had significantly higher serum IS concentrations compared to control cats. No significant difference found between stage 2 and stages 3 and 4 CKD. The pCS concentrations were not significantly different between CKD cats and control cats.Conclusions and Clinical ImportanceDecreased fecal microbiome diversity and richness is associated with CKD in cats. Indoxyl sulfate concentration is significantly increased with CKD, and cats with stage 2 CKD may suffer from a similar uremic toxin burden as do cats with later stage disease.

Factors associated with survival in dogs with chronic kidney disease

Background: Chronic kidney disease (CKD) is associated with morbidity and mortality in dogs. Plasma fibroblast growth factor‐23 (FGF‐23) concentration is an independent predictor of CKD progression and survival in cats and people with CKD. Objectives: To investigate the relationship among FGF‐23, parathyroid hormone (PTH), vitamin D metabolites, and other clinical variables with survival time in dogs with CKD. Animals: Twenty‐seven azotemic CKD dogs. Methods: Dogs were recruited prospectively into the study and followed until death or study conclusion. Dogs were International Renal Interest Society (IRIS) staged into stage 2 (n = 9), stage 3 (n = 12), and stage 4 (n = 6) CKD. Survival times were calculated from the date of study inclusion. Univariable Cox regression was used to assess variables associated with survival including body condition score (BCS), muscle condition score, hematocrit, creatinine, CKD stage, serum phosphorus, urine protein:creatinine ratio (UPC), calcium phosphorus product (CaPP), PTH, 25‐hydroxyvitamin D, 1,25‐‐dihydroxyvitamin D, and FGF‐23 concentrations. Results: Significant hazard ratios (hazard ratio; 95% confidence interval; P value) were as follows: BCS < 4/9 (1.579; 1.003‐2.282; P = .05), muscle atrophy (2.334; 1.352‐4.030; P = .01), increased creatinine (1.383; 1.16‐1.64; .01), hyperphosphatemia (3.20; 1.357‐7.548; P = .005), increased UPC (3.191; 1.310‐7.773; P = .01), increased CaPP (4.092; 1.771‐9.454; P = .003), and increased FGF‐23 (2.609; 1.090‐6.240; P = .05). Survival times for each IRIS CKD stage were significantly different (P = .01). Conclusions and Clinical Importance: Multiple variables, including FGF‐23, were associated with duration of survival in CKD dogs. FGF‐23 could be a prognostic marker in dogs with CKD.

Evaluation of the analytical variability of urine protein-to-creatinine ratio in cats.

Proteinuria quantification with the urinary protein-to-creatinine (UPC) ratio is part of the diagnostic process in feline patients suspected of chronic kidney disease (CKD). In affected cats, monitoring and substaging of the UPC according to the International Renal Interest Society (IRIS) guidelines is also necessary for appropriate patient management. No information is available about the possible effects of analytical variability on urinary proteins (UPs) and the UPC ratio in cats. This study aimed to determine whether imprecision and method-dependent differences due to the two dye-binding methods, pyrogallol red-molybdate (PRM) and Coomassie brilliant blue (CBB), could affect IRIS substaging. Urine samples were collected from proteinuric and nonproteinuric cats. Intra-assay and inter-assay repeatability were assessed with both the PRM and CBB methods. Urinary supernatants (n=120) were tested using both methods. Agreement between the methods and concordance with sample classification according to IRIS guidelines were determined. On average, the PRM method yielded a higher CV (UP 8.4±5.2%; UPC 9.5±4.8%) than the CBB method (UP 5.6±2.6%; UPC 7.2±2.6%), but similar rates of misclassification were found in samples with UPC ratios close to the IRIS cut-off. Although the two methods were correlated, the CBB method tended to yield UPs and UPC ratios that were significantly higher (P<0.0001) than that of the PRM method. The Passing-Bablok test also found constant and proportional errors between the PRM and CBB methods. Concordance in substaging samples according to IRIS was good (k coefficient=0.62). The two methods were precise, but the higher UPC ratios obtained with the CBB methods might affect the interpretation using the IRIS guidelines and clinical decisions.

A nutraceutical diet based on Lespedeza spp., Vaccinium macrocarpon and Taraxacum officinale improves spontaneous feline chronic kidney disease.

Chronic kidney disease is characterized by structural and/or functional impairment of one or both kidneys persisting for more than 3 months. In cats, chronic kidney disease can frequently occur in animals aged over 9 years with an incidence of approximately 10%. Thirty‐four client‐owned, neutered cats, suffering from stage II‐III chronic kidney disease and diagnosed according to the International Renal Interest Society guidelines were randomly assigned to receive either a control diet (n = 17) or a nutraceutical diet (ND; n = 17) for 90 days. Both diets were commercialized for management of CKD symptoms. The diets were identical except that the ND contained tablets that consisted of 60–80% hydrolysed proteins, 20–40% minerals and active substances, that are, Lespedeza spp. 0.0588%, Vaccinium macrocarpom 0.0371%, and Taraxacum officinale 0.0231%. No adverse effects were reported during this study. Both diets resulted in an improvement in CKD symptoms. After a 90‐day evaluation, creatinine, blood urea nitrogen, total proteins, and aspartate aminotransferase significantly decreased in cats that received the ND. A significant decrease was also observed in urine turbidity score, color score, and total proteins in cats that received the ND. We have found that a ND based on Lespedeza spp., Vaccinium macrocarpon, and Taraxacum officinale improves key indicators of renal failure in cats affected by chronic kidney disease.

Urinary cystatin C as biomarker for identification of kidney disease in dogs

The aim of the study was to identify urinary biomarker for early detection of renal dysfunction in dogs. Paired blood and urine samples were analysed from dogs classified on the basis of International Renal Interest Society (IRIS) staging system. Serum biochemistry revealed a highly significant increase in blood urea nitrogen and creatinine levels in dogs with kidney disease. Urinalysis also revealed a highly significant increase in the level of urinary protein and urinary protein creatinine (UPC) ratio in dogs with kidney disease. A highly significant decrease in urinary creatinine and specific gravity level was also present in all groups of dogs with kidney disease. The SDS-PAGE of urinary proteins obtained from dogs with renal failure revealed the presence of low molecular weight (LMW) proteins of 14.7 KDa. This protein was identified as cystatin C protein by Immunoblotting using anti-cystatin C antibody and it has been suggested as biomarker for the diagnosis of renal disease.

A long term feed supplementation based on phosphate binders in Feline Chronic Kidney Disease.

Chronic kidney disease (CKD) is a very common disorder in elderly cats. A proper renal diet represents the most efficient therapeutic intervention to improve survival and life quality in feline patients with 3 and 4 International Renal Interest Society (IRIS) stages. Twenty cats were selected in this study. Ten were administered the dietary supplementation for 360 days and the other ten, whose owners did not give consent for any supplemental therapies apart from the renal diet, were selected from a clinical database and used as control group. The present study is a long term study (360 days) aiming to evaluate the efficacy and palatability of a dietary supplementation containing calcium carbonate, calcium-lactate gluconate, chitosan and sodium bicarbonate in cats diagnosed with 3 and 4 IRIS stages of CKD. The owners were asked to fill in questionnaires to get information on the cat's appetite, the palatability of the given supplement, the presence of vomit and/or diarrhoea, general health and vitality. Hematochemical, biochemical and urinary analyses were performed on day 0, 30, 60, 90, 120, 150,180 and 360. GraphPad Prism® software was used to perform statistical analysis. Our study shows that the given dietary supplement reduced serum phosphorus and increased serum bicarbonate values in cats with CKD. In turn, this supplement could be used as a support therapy in cats with advanced CKD improving their clinical conditions without any adverse reaction. Finally, it is important to underline that all the animals completed the study and the owners reported a good palatability of the feed supplement.

Effects of fenoldopam on kidney function parameters and its therapeutic efficacy in the management of acute kidney injury in dogs with heatstroke.

BackgroundAcute kidney injury (AKI) is common in dogs, but evidence of efficacy of its treatment is lacking.ObjectiveTo evaluate the efficacy of fenoldopam in the management of AKI.AnimalsForty dogs with naturally occurring heatstroke.MethodsDogs were prospectively enrolled and divided into treatment and the placebo groups (fenoldopam, constant rate infusion [CRI] of 0.1 µg/kg/min or saline, respectively). Urine production (UP) was measured using a closed system. Urinary clearances were performed at 4, 12, and 24 hours after presentation to estimate the effect of fenoldopam on UP, glomerular filtration rate (GFR) and sodium fractional excretion (NaFE).ResultsAt presentation, severity of heatstroke, based on a previously developed scoring system, was similar between the study groups, but was significantly worse in nonsurvivors compared with survivors. Fenoldopam administration was not associated with hypotension. Overt AKI was diagnosed, based on the International Renal Interest Society guidelines in 22/40 (55%) of the dogs. Overall, 14/40 dogs (35%) died, with no significant (P = .507) mortality rate difference between the fenoldopam (6/20 dogs; 30%) and placebo (8/20; 40%) groups. The proportion of dogs with AKI did not differ between the fenoldopam and the placebo groups (9/20; 45% versus 13/20; 65%, respectively; P = .204). There were no differences in UP, GFR, and NaFE between the fenoldopam and the placebo groups.Conclusion and Clinical ImportanceFenoldopam CRI at 0.1 µg/kg/min did not have a clinically relevant effect on kidney function parameters in dogs with severe heatstroke‐associated AKI.

Relationship between indirect blood pressure and various stages of chronic kidney disease in cats.

Chronic kidney disease (CKD) is a common cause of secondary systemic hypertension in cats. We investigated the relationship between indirect blood pressure and the prevalence of systemic hypertension in various CKD stages in cats. Client-owned cats (24 control cats and 77 cats with CKD) were included. Biochemical examinations of plasma were conducted by a commercial laboratory. Diseased cats were divided into two groups based on the International Renal Interest Society (IRIS) guidelines (II and III–IV). Indirect blood pressure was measured using an oscillometric technique. Severe hypertension was diagnosed if systolic blood pressure (SBP) was ≥180 mmHg. Indirect blood pressures were significantly higher in IRIS stage III–IV than in the control cats. Of 77 cats with CKD, 25 (32.5%) had severe hypertension. The frequency of severe hypertension increased with an increase in IRIS stage; 0% in the controls, 27.6% in the IRIS stage II, and 47.4% in the IRIS stage III–IV, respectively. The indirect SBP was weakly correlated with urea nitrogen (r=0.27) and creatinine (r=0.23) concentrations in plasma. Binary logistic regression analysis showed that if plasma creatinine concentration is >3.7 mg/dl, cats with CKD had an increased risk for developing severe hypertension (P<0.001). Our results suggest that indirect blood pressure was correlated with the severity of CKD, and the prevalence of severe hypertension increased in cats with severe CKD. The risk of severe hypertension may be high in cats with severe CKD.

Comparative Evaluation of the Echocardiographic Parameters of Dogs with Chronic Mitral Valve Regurgitation Treated with Amlodipine or Pimobendan

Background: Chronic mitral valve regurgitation is the most common heart disease in dogs. It is caused by myxomatous mitral valve degeneration, an acquired degenerative disease that can lead to congestive heart failure. Pimobendan is a mixed action drug, with inotropic and vasodilator proprieties, widely used to treat such dogs. Amlodipine is a pure vasodilator drug used as an anti-hypertensive agent, with no inotropic effects. This study aimed to compare echocardiographic, electrocardiographic and blood pressure parameters between dogs with congestive heart failure treated with pimobendan and those treated with amlodipine in addition to conventional therapy.Materials, Methods &amp; Results: A prospective, randomized, double-blind study was conducted in dogs with stage C chronic mitral valve regurgitation according to the 2009 American College of Veterinary Internal Medicine (ACVIM) guidelines, who weighed up to 15 kg. Randomization was performed using appropriate software and the sealed envelope technique. Blinding of the owner, the main researcher, and the person who performed the clinical analysis was guaranteed by the use of identical capsules and bottles for both pimobendan and amlodipine. Statistical analysis was performed using specialized software. Eligibility was determined by predefined inclusion and exclusion criteria. Dogs with cardiac disease other than mitral and/or tricuspid degeneration, patients already undergoing pharmacological treatment with drugs other than enalapril and furosemide, patients with systolic blood pressure below 100 mmHg, patients with chronic kidney disease in stages III or IV according to International Renal Interest Society staging system for chronic kidney disease (2009), and patients with other systemic debilitating diseases were excluded from the study. The animals were randomized into two groups based on the drug they received. Group A received pimobendan (n = 10) and group B received amlodipine (n = 11). All animals were also treated with furosemide and enalapril maleate and evaluated three times over a period of sixty days (T0, T30, T60). Changes in echodopplercardiographic and electrocardiographic parameters and systolic blood pressure were investigated. There were no significant differences in electrocardiographic parameters or systolic blood pressure between the groups at any time. Among the echocardiographic parameters, only early diastolic myocardial peak velocity (Em) and late diastolic myocardial peak velocity (Am) showed a significant difference between groups.Discussion: This was the first prospective randomized double-blind study comparing pimobendan and amlodipine in the treatment of dogs with stage C chronic mitral valve regurgitation according to the ACVIM consensus statement. The use of pimobendan in these patients has been debated because myocardial inotropism is generally preserved in them. Some authors argue that early use of the drug can even lead to deleterious effects on the heart. In the present study, the groups showed no statistically significant differences in systolic blood pressure or electrocardiographic parameters. Among the echocardiographic parameters, statistically significant differences were only observed in the speed of Em waves between groups at T0, in the speed of Em waves in the amlodipine group between T0 and T60 times, and in the speed of Am waves in the amlodipine group between T30 and T60 times. Both parameters are indices of diastolic function and may indicate a change in early myocardial relaxation. From the findings of this study, we could not conclude whether one drug was superior to the other.

Plasma indoxyl sulfate concentration predicts progression of chronic kidney disease in dogs and cats

Indoxyl sulfate is a protein-bound uremic toxin that increases as the severity of impaired renal function increases in humans, laboratory animals, dogs and cats. An elevation of indoxyl sulfate is related to prognosis among people with chronic kidney disease. However, whether indoxyl sulfate is able to predict the progression of chronic kidney disease in dogs and cats has not been previously studied. In the present study, 58 cats and 36 dogs with chronic kidney disease were enrolled. Plasma indoxyl sulfate was measured by high performance liquid chromatography. Renal progression was defined as an increase by one International Renal Interest Society (IRIS) stage and/or a rise in serum creatinine concentration of 0.5mg/dL during the same stage within a 3-month period.Compared with the non-progression groups, across different stages of renal failure, the baseline plasma indoxyl sulfate concentration was increased in the renal progression group (P<0.05), especially for IRIS stages 2 and 3 animals. The area under the receiver operator characteristic curves of indoxyl sulfate, when predicting renal progression, was above 0.75 for both dogs and cats. Indoxyl sulfate concentrations were also correlated with the increase of blood urea nitrogen, serum creatinine, and phosphate and the decrease of hematocrit among cats; while in dogs, concentrations were only correlated with the increase of phosphate concentrations. Indoxyl sulfate served as a biomarker of progression risk in dogs and cats with chronic kidney disease.

Innovations in nutritional therapy for cats with chronic kidney disease

Kidney disease is the second most common cause of death in cats. The management of chronic kidney disease (CKD) has evolved with nutrition playing a prominent role in the management. A new test has been developed that can detect kidney disease sooner than traditional tests: SDMA (symmetric dimethylarginine). Earlier diagnosis using SDMA and the International Renal Interest Society (IRIS) guidelines may allow earlier nutritional intervention in cats with CKD. The goal for a cat is to provide adequate nutrition, which will lead to improved quality and length of life. The overarching goals of CKD management are to: control clinical signs of uraemia; maintain adequate fluid, electrolyte, and acid–base balance; provide adequate nutrition; and minimise progression of kidney disease. Nutritional management plays a role in each goal and is the cornerstone of treatment for cats with CKD.

Systemic hypertension in cats with acute kidney injury.

To describe the prevalence of systemic hypertension in cats with community-acquired acute kidney injury and investigate its relationship with disease severity. Retrospective study of cats presenting to the Queen Mother Hospital for Animals, Royal Veterinary College with acute kidney injury between 2007 and 2015. Systolic blood pressure was measured using Doppler sphygmomanometry and systemic hypertension was defined pressures ê150 mmHg. Median systolic blood pressure measurement, grade of acute kidney injury (as defined by the International Renal Interest Society), serum creatinine on admission, anuria or oliguria, length of hospitalisation, survival to discharge and six-month survival were all recorded. Forty-six cats were included; 21/48 (48.8%) showed systemic hypertension on admission and was severe (ê180 mmHg) in 8/43 (18.6%). During the whole hospitalisation period, systemic hypertension was detected in 27/46 (58.7%) cases and severe in 13/46 (28.2%). Systemic hypertension did not appear to be statistically associated with grade of kidney injury, serum creatinine on presentation, oliguria or anuria. Systemic hypertension is common in cats with acute kidney injury but does not appear to be associated with its severity.

Serum fibroblast growth factor 23 concentrations in dogs with chronic kidney disease

The aim of this study was to determine if serum fibroblast growth factor (FGF23) concentrations were increased in dogs with chronic kidney disease (CKD). Serum samples submitted to a commercial laboratory were collected over a 15-month period, 14 samples were from dogs with a history of polyuria/polydipsia, azotaemia and low urine specific gravity, 20 samples were from non-azotaemic dogs. Serum FGF23, parathyroid hormone, total calcium and phosphorus, urea and creatinine were measured. Mann-Whitney test was used to determine differences between non-azotaemic and CKD groups; a one-way ANOVA with Tukey pairwise comparisons was used to determine any differences between International Renal Interest Society stages; and regression models were used to determine predictors of International Renal Interest Society stage, serum phosphorus and FGF23 concentrations. The median serum FGF23 concentration of dogs with CKD was 5194.6pg/mL, which was significantly greater (P<0.001) than the median serum FGF23 concentration of non-azotaemic dogs (259.2pg/mL). Log serum FGF23 and age were significantly associated with IRIS stage (P=0.027 and P=0.032 respectively), while log serum phosphorus concentration (P<0.001) was significantly associated with log serum FGF23 concentration. In summary, serum FGF23 concentration is increased in dogs with CKD, and is associated with serum phosphorus concentration. This phosphatonin pathway may be a useful target for the development of future treatments to control plasma phosphorus concentrations in chronic kidney disease.

Glomerular Lipidosis in Dogs.

Glomerular lipidosis (GL) is characterized by dilated glomerular capillary loops containing lipid-laden cells (foam cells). Previously, GL was considered to be an incidental finding because affected dogs were typically not azotemic. However, the International Renal Interest Society staging system for canine chronic kidney disease has increased the awareness of other clinical parameters (eg, proteinuria and hypertension) that should be included in the assessment of renal function. As such, the aim of this study was to determine clinical abnormalities and concurrent renal lesions in dogs with GL. GL was identified in renal biopsies from 46 dogs evaluated by the International Veterinary Renal Pathology Service. GL was the sole diagnosis in 5 of 46 cases (11%), all of which were proteinuric. All 5 dogs had at least 1 additional clinicopathologic abnormality consistent with renal disease, including hypertension (4), azotemia (3), and/or hypoalbuminemia (2). The remaining 41 dogs had GL in combination with other glomerular lesions, the most common being focal segmental glomerulosclerosis (16, 35%), lesions consistent with juvenile nephropathy (8, 17%), and glomerular amyloidosis (5, 11%). Overall, dogs with severe GL were younger than were those with mild GL ( P < .001). The percentage of glomeruli affected by GL differed by concurrent diagnoses ( P = .034), with the highest percentage of affected glomeruli in dogs with GL alone or those with concurrent juvenile nephropathy. These findings suggest that GL should be a recognized histologic phenotype of glomerular injury associated with clinical renal dysfunction and/or juvenile nephropathies.

Relation between anaemia and bone marrow features and serum erythropoietin in dogs with chronic kidney disease

ABSTRACT: Chronic anaemia is one of the most severe complications of chronic kidney disease, contributing to morbidity and mortality caused by the disease; therefore, bone marrow cytological evaluation is needed to monitor the progression of anaemia. This study aimed to correlate the anaemia in dogs at different stages of chronic kidney disease with their serum biochemistry, myelogram results and serum erythropoietin findings. Sixty-three dogs were grouped according to International Renal Interest Society (IRIS) classification in stages 1, 2, 3 and 4. Haematologic, serum and urinary biochemistry and serum erythropoietin were performed for comparison with the findings of bone marrow cytology obtained by aspiration of the manubrium. Cytological findings for erythroid hypoplasia were described in 93.65% of dogs, and the anaemia was observed in 84.1% of them. The haematological findings were correlated with azotaemia (p&lt;0.05). It was concluded that the erythroid hypoplasia has correlation with persistent anaemia in dogs at all stages of chronic kidney disease, with iron deficiency in dogs in the early stages and with peripheral destruction of erythrocytes caused by azotaemia.

Evaluation for association between urolithiasis and chronic kidney disease in cats.

OBJECTIVE To determine whether urolithiasis is associated with chronic kidney disease (CKD) in cats. DESIGN Retrospective case-control study. ANIMALS 126 cats (59 and 67 with and without urolithiasis, respectively). PROCEDURES Medical records from June 2006 to July 2013 were searched to identify cats that underwent abdominal or focal urinary tract ultrasonography and for which serum creatinine concentration and urine specific gravity data were obtained ≤ 14 days before or after the examination. In cats with (urolithiasis group) and without (control group) urolithiasis, the presence of CKD was determined according to International Renal Interest Society guidelines. Information recorded included signalment, body weight, serum creatinine concentration, and urine specific gravity; when present, the location and number of uroliths were noted. Differences between groups and associations between group and categorical variables were analyzed statistically. RESULTS Age, weight, sex, and breed did not differ between groups. The prevalence of CKD was significantly higher in cats with urolithiasis than in the control group. Among cats with urolithiasis, there was a negative association between CKD and presence of cystoliths. There was no association between urolithiasis and the stage of CKD or between presence of CKD and location of nephroliths in the kidney. CONCLUSIONS AND CLINICAL RELEVANCE Results confirmed a positive association between urolithiasis and CKD in the feline population studied and suggested that cats with urolithiasis should be evaluated for CKD. Further research is warranted to assess the nature of the relationship between CKD and urolithiasis in cats.