Glomerular filtration rate in dogs with leishmaniasis and chronic kidney disease

BACKGROUND: Glomerular filtration rate (GFR) measurement is an indicator of kidney function. However, its usefulness in dogs at early stages of spontaneous chronic kidney disease (CKD) of glomerular origin, where routine laboratory techniques are not sufficiently sensitive, remains unproved. HYPOTHESIS: That GFR is reduced in proteinuric nonazotemic or mildly azotemic dogs with CKD secondary to leishmaniasis. ANIMALS: Twenty-six dogs with CKD secondary to leishmaniasis and 10 healthy dogs (control group). METHODS: CBC, serum biochemistry, and urinalysis (microalbuminuria and urine protein/creatinine ratio [UPC]) were performed in all dogs. GFR was calculated by measuring exogenous creatinine clearance. Based on degree of proteinuria and serum creatinine concentration (SCr), dogs were classified as group A (control; n = 10): UPC < 0.2, SCr < 1.4 mg/dL; group B (n = 8): UPC, 0.2-0.5, SCr < 1.4 mg/dL; group C (n = 10): UPC > 0.5, SCr < 1.4 mg/dL; group D (n = 5): SCr, 1.4-2 mg/dL; group E (n = 3): SCr > 2 mg/dL. Results: GFR (mL/kg/min) was 3.9 +/- 0.29, 4.4 +/- 0.74, 4.5 +/- 1.44, 2.8 +/- 0.97, and 1.5 +/- 0.43 for groups A, B, C, D, and E, respectively. Eleven dogs (1 from group B, 3 from group C, 4 from group D, and all 3 dogs from group E) had an abnormally low GFR. Four dogs from group B and 5 dogs from group C had a GFR above the upper reference range (>4.5 mL/min/kg). CONCLUSION AND CLINICAL RELEVANCE: Some proteinuric nonazotemic or mildly azotemic dogs with leishmaniasis have low GFR, but glomerular hyperfiltration occurs in other dogs.     

Evaluation of biological variance of cystatin C in comparison with other endogenous markers of glomerular filtration rate in healthy dogs

BACKGROUND: The aim of the study was to investigate and compare components of variance of endogenous markers of glomerular filtration rate (GFR) in healthy dogs and impact on the interpretation of results. HYPOTHESIS: Cystatin C (cysC) in the dog is superior to creatinine (crea) and urea in detecting decreased renal function because of a high index of individuality (IoI). ANIMALS AND METHOD: Variance components of cysC, crea (2 methods: creaE, creaJ), urea, and inorganic phosphate (Pi) in plasma were determined in a longitudinal study over 6 months in 24 healthy dogs (6 German Shorthair Pointers, 18 Beagles). IoI and critical differences (CD) were calculated, as well as the numbers of measurements necessary to determine the individual's homeostatic set point. Results: Mean concentrations of cysC, creaJ, creaE, urea, and Pi (mean +/- SD) were 0.93 +/- 0.19 mg/L, 0.94 +/- 0.17 mg/dL, 0.76 +/- 0.18 mg/dL, 35.34 +/- 9.08 mg/dL, and 3.74 +/- 0.68 mg/dL, respectively. The IoI for cysC, creaJ, creaE, urea, and Pi were 0.96, 0.89, 0.80, 0.90, and 1.16, respectively. The C(D) for cysC, creaJ, creaE, urea, and Pi were 0.37 mg/L, 0.26 mg/dL, 0.27 mg/dL, 16.94 mg/dL, and 1.45 mg/dL, respectively. CONCLUSION: In dogs, components of biological variance of cysC and crea are in the same range. Analytical precision requirements were fulfilled by crea(both), urea, and Pi. All parameters had an intermediate IoI, which allowed the application of population-based reference limits. The application of the CD for crea or cysC might be useful in detecting a decrease of GFR, when sequential measurements in an individual reveal an increase exceeding the CD but not the upper reference limit.     

Investigation of renal protein loss in dogs with acute experimentally induced Ehrlichia canis infection.

Urinary protein-to-creatinine ratios and serum albumin concentrations were measured in 8 adult male dogs experimentally inoculated with Ehrlichia canis. Urinary protein concentration increased significantly, but transiently, during the acute phase of infection. Urinary protein-to-creatinine ratios were highest (mean, 8.6) during the third and fourth weeks after infection, and decreased to less than 0.5 by 6 weeks after infection. Correspondingly, albumin concentration decreased significantly during the acute phase. Serum albumin concentrations were lowest (mean, 2.1 g/dl) the fourth week after infection and increased to greater than 3.0 g/dl by 11 weeks after infection. There was an inverse linear correlation between urinary protein-to-creatinine ratio and serum albumin concentration. The magnitude of proteinuria and its inverse relationship with serum albumin concentration suggested that hypoalbuminemia associated with acute E canis infection may be attributable primarily to increased renal loss of protein, rather than decreased hepatic synthesis as previously suggested. Another dog was subsequently inoculated with E canis from 1 of the experimentally infected dogs and a renal biopsy was performed during peak proteinuria (urinary protein-to-creatinine ratio = 22 and serum albumin = 1.1 g/dl). Immunofluorescent staining revealed mild to moderate deposits of anti-canine IgM, and to a lesser extent, anti-canine IgG and complement factor C3 in the glomerular tufts and mesangium. Ultrastructural evaluation revealed distortion and fusion of podocyte foot processes and increased microvilli on podocytes. These morphologic changes were consistent with transient glomerular leakage of protein of a magnitude that would significantly contribute to hypoalbuminemia during acute E canis infection. An underlying immunologic mechanism was suggested by positive glomerular immunofluorescence and previously described histologic findings.     

Chronic canine ehrlichiosis (Ehrlichia canis): a retrospective study of 19 natural cases

Nineteen dogs from Greece with chronic ehrlichiosis were studied. The dogs exhibited bicytopenia or pancytopenia, bone marrow hypoplasia, seroreactivity to Ehrlichia canis (E. canis) antigens, and had no history of drug or radiation exposure. Anorexia, depression, severe bleeding tendencies, hypoalbuminemia, and increased serum alanine aminotransferase activity were also hallmarks of the disease. All these animals eventually died, irrespective of the treatment applied. Some dogs were also serologically positive for Rickettsia conorii, Leishmania infantum (L. infantum), and Bartonella vinsonii subspp. berkhoffii. Polymerase chain reaction testing of bone marrow samples revealed E. canis, Anaplasma phagocytophilia, Anaplasma platys, and L. infantum in some dogs. Concurrent infections did not appear to substantially influence the clinical course and final outcome of the chronic canine ehrlichiosis.     

Acute intrinsic renal failure in cats: 32 cases (1997-2004)

OBJECTIVE: To determine patient demographics, clinicopathologic findings, and outcome associated with naturally acquired acute intrinsic renal failure (ARF) in cats. DESIGN: Retrospective case series. ANIMALS: 32 cats with ARF. PROCEDURES: Cats were considered to have ARF if they had acute onset of clinical signs (< 7 days), serum creatinine concentration > 2.5 mg/dL (reference range, 0.8 to 2.3 mg/dL) and BUN > 35 mg/dL (reference range, 15 to 34 mg/dL) in conjunction with urine specific gravity < 1.025 or with anuria or increasing serum creatinine concentration despite fluid therapy and normal hydration status, and no signs of chronic renal disease. Cases were excluded if cats had renal calculi or renal neoplasia. RESULTS: Causes of ARF included nephrotoxins (n = 18 cats), ischemia (4), and other causes (10). Eighteen cats were oliguric. For each unit (mEq/L) increase in initial potassium concentration, there was a 57% decrease in chance of survival. Low serum albumin or bicarbonate concentration at initial diagnosis was a negative prognostic indicator for survival. Initial concentrations of BUN, serum creatinine, and other variables were not prognostic. Seventeen (53%) cats survived, of which 8 cats had resolution of azotemia and 9 cats were discharged from the hospital with persistent azotemia. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that survival rates of cats with ARF were similar to survival rates in dogs and that residual renal damage persisted in approximately half of cats surviving the initial hospitalization.     

Peritoneal dialysis in the management of acute renal failure in 5 dogs with leptospirosis

Objective: To describe the use of peritoneal dialysis (PD) in the management of 5 dogs with acute renal failure (ARF) caused by leptospirosis. Case Series Summary: All dogs were treated for leptospirosis with intravenous (IV) fluids and ampicillin prior to PD. Median age of dogs was 5 years (range 2–6 years). All dogs had positive titers for Leptospira bratislava. Median duration of PD was 4 days (range 3–16 days). PD resulted in a decrease in azotemia in all dogs. Median serum blood urea nitrogen at the start of PD was 192 mg/dL (range 140–235 mg/dL) and at the end of PD was 63 mg/dL (range 48–139 mg/dL). Median serum creatinine at the start of PD and the end was 12.8 mg/dL (range 7.7–16.9 mg/dL) and 3.4 mg/dL (range 1.4–11.1 mg/dL), respectively. Complications identified during PD included hypokalemia (n=3, 60%), hypoalbuminemia (n=2, 40%), hypomagnesemia (n=1, 20%), pelvic limb edema (n=2, 40%), central nervous system signs (n=2, 40%), dialysate retention (n=1, 20%), and leakage from the catheter site (n=1, 20%). Peritonitis was not identified in any of the dogs. Four dogs (80%) survived to discharge from the hospital. PD was effective for management of uremia in dogs with ARF caused by leptospirosis.     

Association of gastrointestinal hemorrhage with increased blood urea nitrogen and BUN/creatinine ratio in dogs: a literature review and retrospective study

Blood urea nitrogen (BUN) and serum creatine concentrations were recorded from the medical records of 52 dogs with clinical evidence for upper gastrointestinal hemorrhage (UGH) at the Colorado State University Veterinary Teaching Hospital between 1988 and 1995. Eighteen of the dogs had melena, 11 dogs had hematemesis, and 23 dogs had both melena and hematemesis. Compared with age-matched control dogs, dogs with suspected UGH had a significantly higher BUN concentration (31.0 mg/dL vs. 16.5 mg/dL), creatinine concentration (1.2 mg/dL vs. 1.1 mg/dL) and BUN/creatinine ratio (27.6 vs. 14.4). The increase in BUN/creatinine ratio suggested that the increased BUN concentration in dogs with evidence for UGH primarily was associated with increased gastrointestinal absorption of nitrogenous compounds, and hepatic ureagenesis.     

Are urea and creatinine values reliable indicators of azotaemia in canine babesiosis?

Serum urea and creatinine are extensively used as parameters to screen for azotaemia. Their reciprocal plots roughly correlate with glomerular filtration rate (GFR). They are, however, subject to influence by non-renal factors and to increase their specificity they are often tested concurrently. In renal disease they are expected to behave similarly, with both parameters increasing as GFR decreases. Haemolysis, as it occurs in canine babesiosis, may cause non-renal elevations in serum urea, possibly due to ammonia loading. Furthermore, haemolysis with its related elevations in serum bilirubin and serum haemoglobin, may negatively bias the measurement of serum creatinine due to interference of these substances with the chemical analysis of serum creatinine. This negative bias occurs when the alkaline picrate method, or when direct enzymatic methods based on the measurement of hydrogen peroxide, are used. In order to investigate the significance of these perturbations in canine babesiosis, paired values of serum urea and serum creatinine from Babesia canis-negative, non-haemolysis dogs (Group 1), were used to establish a relationship between urea and creatinine over a range of azotaemia by linear regression analysis. This relationship was then used to predict serum creatinine values from actual serum urea values in B. canis-positive dogs (Group 2). The mean of the predicted serum creatinine values for Group 2 (237.03 micromol/l) was then compared with the mean of the actual serum creatinine values for Group 2 (131.31 micromol/l). For Group 2, the mean actual serum creatinine demonstrated a significant negative bias relative to the mean predicted creatinine value. There was also a higher correlation between serum urea and serum creatinine in Group 1 than in Group 2. These findings may have been caused by either nonrenal elevations of serum urea values or by interference with the measurement of serum creatinine. Therefore, although it is possible that some Group 2 dogs with B. canis with high serum urea and normal, low, or zero values for serum creatinine were not azotaemic, it is also possible that other Group 2 dogs with these biochemical findings did in fact have azotaemia. This study concluded that urea and creatinine do not behave in a similar and predictable manner over a range of azotaemia in canine babesiosis and are therefore not ideally suited for the detection of renal disease in this clinical setting.     

Use of continuous renal replacement therapy for treatment of dogs and cats with acute or acute-on-chronic renal failure: 33 cases (2002–2006)

Objective: To describe the indications, clinical features, outcomes and complications associated with use of continuous renal replacement therapy (CRRT) in 17 client-owned dogs and 16 client-owned cats with acute or acute-on-chronic renal failure refractory to aggressive medical management.
Series summary: Twenty-nine percent of dogs and 44% of cats had evidence of pre-existing chronic kidney disease (CKD). Median duration of CRRT was 16.3 hours (range 0.3–83.0 hours) in dogs and 11.5 hours (range 1.0–35.5 hours) in cats. Median canine blood urea nitrogen (BUN) improved from 41.0 mmol/L (115.0 mg/dL) to 11.8 mmol/L (33.0 mg/dL) and creatinine from 636.5 mmol/L (7.2 mg/dL) to 274 mmol/L (3.1 mg/dL). Median feline BUN improved from 46.4 mmol/L (130 mg/dL) to 13.9 mmol/L (39.0 mg/dL) and creatinine from 1069.6 mmol/L (12.1 mg/dL) to 291.7 mmol/L (3.3 mg/dL). Metabolic acidosis resolved in 80% of affected dogs and 71% of affected cats. Hyperkalemia resolved in 100% of affected dogs and 88% of affected cats. Complications noted with CRRT included iatrogenic hypokalemia, iatrogenic metabolic alkalosis, clinical hypocalcemia, total hypercalcemia, filter clotting, anemia, hypothermia, and neurologic complications. Forty-one percent of dogs and 44% of cats survived to discharge. No dogs and only 1 cat developed newly diagnosed CKD.
New or unique information provided: CRRT can be a viable option for the management of acute or acute-on-chronic renal failure in dogs and cats that are refractory to aggressive medical management. The frequency of complications associated with CRRT in this study warrants further experience with this modality before its widespread use can be recommended.     

A Retrospective Case-Control of Acute Renal Failure in 99 Dogs

The objective of this study was to evaluate retrospectively demographic and clinicopathologic factors that may be associated with the diagnosis and outcome of acute renal failure (ARF) in dogs presented to a large referral hospital. Medical records of dogs presented to the hospital were searched for a diagnosis of ARF. The diagnosis of ARF was based on clinical signs, renal imaging findings, and clinicopathologic data and, in most cases, was confirmed by histopathology, prior serum creatinine concentrations, response to therapy, and known recent nephrotoxin exposure or ischemic event. Demographics, selected clinicopathologic findings, and concurrent disorders that may have been associated with development of ARF were extracted from these records. A reference population was derived from 481 dogs presenting to the same hospital. Demographic data also were collected from these medical records. The demographic factors associated with a diagnosis of ARF and the factors associated with outcome of ARF were assessed by reviewing a series of multiple logistic regression models. Conclusions from this study were as follows: (1) Intact male dogs and nonsporting dogs were more likely to develop ARF and be admitted to the teaching hospital. (2) Dogs with severe azotemia (serum creatinine concentration > 10 mg/dL), hypocalcemia (<8.6 mg/ dL), and proteinuria were less likely to survive ARF and be discharged from the hospital. (3) Dogs that survived in the hospital for more than 5 days were more likely to recover and be discharged from the hospital.     

Doxycycline clearance of experimentally induced chronic Ehrlichia canis infection in dogs

BACKGROUND: Ineffective clearance of Ehrlichia canis after doxycycline administration has been reported despite the fact that the recommended treatment for canine ehrlichiosis is doxycycline. The effectiveness of doxycycline in clearing E canis infection from the blood and tissues of dogs requires additional evaluation. HYPOTHESIS: Doxycycline (5 mg/kg PO q12h), administered for 4 weeks, will eliminate E canis infection from the blood and tissues of experimentally infected dogs. ANIMALS: Fifteen Walker hound-mixed breed dogs were inoculated subcutaneously with E canis-infected canine histiocytic cells 4 months before doxycycline treatment. METHODS: Four dogs were treated with doxycycline (5 mg/kg PO q12h for 3 weeks), 5 dogs were treated with doxycycline at the same dosage for 4 weeks, and 5 control dogs were not treated. Dexamethasone (0.4 mg/kg i.v.) was given after treatment to precipitate recrudescence of any remaining E canis organisms. Platelet counts, anti-E canis immunofluorescent antibodies, and polymerase chain reaction (PCR) detection of E canis deoxyribonucleic acid (DNA) in blood and tissues were evaluated. RESULTS: E canis DNA was not detected in the blood and tissues of doxycycline-treated dogs after treatment. Platelet counts were within reference intervals, and E canis antibodies decreased. Spontaneous clearance of E canis infection occurred in 2 of 5 control dogs. Three control dogs had E canis DNA detected in blood and tissues, platelet counts remained low or within the reference interval, and E canis antibodies remained high. CONCLUSIONS AND CLINICAL IMPORTANCE: As administered in this study, doxycycline cleared E canis from the blood and tissues of experimentally infected dogs.     

The effects of hydrocortisone on systemic arterial blood pressure and urinary protein excretion in dogs

BACKGROUND: Hypertension and proteinuria are commonly recognized in dogs with spontaneous hypercortisolism. There is, however, little information regarding the effect of exogenous glucocorticoids on blood pressure (BP) and proteinuria and whether these changes are reversible. HYPOTHESIS: Hydrocortisone administration increases systemic BP and urinary protein excretion, and these effects are reversible after hydrocortisone withdrawal. Animals: Six control dogs and 6 dogs treated with hydrocortisone. METHODS: BP, urine protein : creatinine ratio (UPC), microalbuminuria (MALB), urine albumin : creatinine ratio (UAC), and urine gel electrophoresis were evaluated before, during, and after administration of hydrocortisone (8 mg/kg PO q12h for 12 weeks) or placebo. RESULTS: BP and UPC increased substantially during hydrocortisone administration from 123 mmHg (range 114-136 mmHg) and 0.17 (0.15-0.28) to a maximum of 143 mmHg (128-148 mmHg) and 0.38 (0.18-1.78), respectively, on day 28. MALB developed in 4 dogs and UAC significantly increased in all dogs during hydrocortisone administration with the maximum on day 84. Both increases in BP and proteinuria were reversible and completely resolved within 1 month after stopping hydrocortisone administration. SDS-AGE revealed the proteinuria to be primarily albuminuria with a pronounced increase during hydrocortisone treatment. Furthermore, a protein of 25-30 kDa was found in male dogs, identified by mass spectrometry to be arginine esterase, the major secretory prostatic protein. CONCLUSIONS AND CLINICAL IMPORTANCE: Long-term hydrocortisone treatment results in significant but only mild increases in systemic BP and urinary protein excretion, which are both reversible within 1 month after discontinuation of hydrocortisone.     

Antibodies to Ehrlichia canis, Ehrlichia platys, and Spotted Fever Group Rickettsiae in Louisiana Dogs

Antibodies to Ehrlichia canis, Ehrlichia platys, and spotted fever group (SFG) rickettsiae were detected by indirect immunofluorescence in sera from 27 ill individually owned thrombocytopenic dogs (platelet concentrations less than 200,000 platelets/microliters) and 59 healthy kenneled dogs located in southern Louisiana. Platelet concentrations less than 100,000 platelets/microliters were detected in 63% of ill thrombocytopenic dogs and 6.8% of healthy kennel dogs. One ill thrombocytopenic dog had intracytoplasmic E platys morulae detected within platelets. The prevalence of increased serum antibody titers to E canis and E platys was 25.9% and 40.7% for the ill thrombocytopenic dogs and 20.3% and 54.2% for the healthy kennel dogs, respectively. All dogs with seropositivity to E canis had increased antibody titers of greater than or equal to 1:100 to E platys. Simultaneous examination of increased serum antibody titers (greater than or equal to 1:64) to four SFG rickettsiae indicate that Rickettsia rhipicephali and Rickettsia montana accounted for the majority of the antibodies detected in these dogs. Of 86 dogs tested, 44.2% were seronegative to E canis, E platys, and SFG rickettsiae.     

Antinuclear antibodies can be detected in dog sera reactive to Bartonella vinsonii subsp. berkhoffii, Ehrlichia canis, or Leishmania infantum antigens

The presence of antinuclear antibodies (ANAs) is used to support a clinical diagnosis of systemic lupus erythematosus (SLE) in dogs. However, clinicians must interpret the detection of ANAs with caution, particularly in light of increasing evidence that dogs with known bacterial and protozoal infections can have high ANA titers. Retrospectively, medical records were reviewed for all dogs that were concurrently tested for antinuclear antigens and Bartonella vinsonii (berkhoffii), Ehrlichia canis, or Rickettsia rickettsii antigens between 1990 and 2000. When analyzed on the basis of reactivity to a specific infectious agent, 75% of the B vinsonii (berkhoffii) seroreactors, 16.7% of the E canis seroreactors, and 0% of the R rickettsii seroreactors had concurrent ANAs. Subsequent prospective testing did not detect ANAs in convalescent sera from dogs experimentally infected with B vinsonii (berkhoffii), E canis, or R rickettsii. However, 10-20% B vinsonii (berkhoffii), E canis, or Leishmania infantum reactive sera from naturally infected dogs contained ANAs. In addition, 45% of sera from dogs that are reactive to multiple vectorborne organisms were more likely to contain ANAs when compared to sera from dogs reactive to only 1 test antigen. When interpreting the relevance of seroreactivity to nuclear antigens, clinicians should recognize that dogs with seroreactivity to B vinsonii (berkhoffii), E canis, or L infantum antigens (especially those with seroreactivity to more than one of these pathogens) may produce ANAs.     

Determination of calcium fractionation in dogs with chronic renal failure

OBJECTIVE: To determine concentrations of calcium (total [tCa], ionized [iCa], protein-bound [pCa], and complexed [cCa]) in dogs with chronic renal failure (CRF). ANIMALS: 23 dogs with CRF. PROCEDURE: Serum calcium was fractionated by use of a micropartition system. Total calcium and iCa concentrations and pH were measured in unfractionated serum, and tCa concentration was measured in the ultrafiltrate. The pCa fraction was calculated by subtracting tCa of the ultrafiltrate from tCa concentration of unfractionated serum. The iCa concentration in unfractionated serum was subtracted from tCa concentration in the ultrafiltrate to determine the concentration of cCa. RESULTS: Concentrations of tCa, iCa, pCa, and cCa had wide ranges among dogs with CRF Dogs with significantly low tCa concentration (770 +/- 1.73 mg/dL) had cCa concentration (0.76 +/- 0.38 mg/dL) within reference range, whereas dogs with reference range to high tCa concentration (10.85 +/- 1.13 mg/dL) had significantly high cCa concentration (2.62 +/- 1.04 mg/dL). There was no significant difference in iCa or pCa concentrations between groups. CONCLUSIONS AND CLINICAL RELEVANCE: Concentrations of tCa, iCa, cCa, and pCa varied widely in dogs with CRF Overall, cCa concentration was high, although subpopulations differed in cCa and tCa concentrations. Differences in tCa concentration were primarily attributable to differences in cCa fraction.     

Effects of long-term administration of enalapril on clinical indicators of renal function in dogs with compensated mitral regurgitation

OBJECTIVE: To determine the effect of long-term administration of enalapril on renal function in dogs with severe, compensated mitral regurgitation. DESIGN: Randomized controlled trial. ANIMALS: 139 dogs with mitral regurgitation but without overt signs of heart failure. PROCEDURE: Dogs were randomly assigned to be treated with enalapril (0.5 mg/kg [0.23 mg/lb], PO, q 24 h) or placebo, and serum creatinine and urea nitrogen concentrations were measured at regular intervals for up to 26 months. RESULTS: Adequate information on renal function was obtained from 132 dogs; follow-up time ranged from 0.5 to 26 months (median, 12 months). Mean serum creatinine and urea nitrogen concentrations were not significantly different between dogs receiving enalapril and dogs receiving the placebo at any time, nor were concentrations significantly different from baseline concentrations. Proportions of dogs that developed azotemia or that had a +/- 35% increase in serum creatinine or urea nitrogen concentration were also not significantly different between groups. Conclusions: And Clinical Relevance: Results suggest that administration of enalapril for up to 2 years did not have any demonstrable adverse effects on renal function in dogs with severe, compensated mitral regurgitation.     

The elevated serum urea:creatinine ratio in canine babesiosis in South Africa is not of renal origin

Pigmented serum, usually due to free haemoglobin and/or bilirubin, is a common finding in dogs with babesiosis, resulting in interference with all biochemical tests that rely on photochemistry. This is particularly true of urea and creatinine determinations, complicating the diagnosis of acute renal failure, which is a serious complication of babesiosis. A disproportionately raised serum urea concentration of unknown origin occurs in severely anaemic canine babesiosis patients and gives rise to an increased serum urea:creatinine ratio. The assay for cystatin-C, an excellent measure of glomerular filtration rate, is unaffected by free serum haemoglobin, and due to its different intrinsic origins, is free of influence by the metabolic derangements and organ pathology, other than renal disease, encountered in canine babesiosis. Serum cystatin-C was used to compare the concentrations of serum urea and serum creatinine in dogs with the severely anaemic form of canine babesiosis as well as a canine babesiosis-free reference group. Mean serum urea and mean serum urea:creatinine ratio were significantly elevated in the babesia-infected group relative to the reference population in this study. Mean serum creatinine and mean serum cystatin-C were within the reference ranges. Therefore an elevated urea:creatinine ratio in canine babesiosis in the presence of a normal serum creatinine concentration is considered to be caused by an elevated serum urea concentration and is most likely of non-renal origin. Serum creatinine was therefore as specific a measure of renal function as serum cystatin-C in canine babesiosis in this study. The sensitivity of serum creatinine as a measure of renal function was not established by this study. Serum urea, however, proved to be of little use compared to serum cystatin-C and serum creatinine. Serum urea should therefore not be used to diagnose renal failure in canine babesiosis.     

Comparison of glomerular filtration rate between greyhounds and non-Greyhound dogs

Greyhounds have significantly higher serum creatinine (SCr) concentration than do non-Greyhound dogs that may be attributable to differences in glomerular filtration rate (GFR). By means of plasma clearance of technetium Tc 99m diethylenetriaminepentaacetic acid, GFR was measured in 10 Greyhounds and 10 non-Greyhound dogs with normal findings of physical examination, CBC, serum biochemical analysis, and urinalysis. Dogs were fed the same diet for a minimum of 6 weeks before GFR data collection. Greyhounds had significantly higher mean +/- SD GFR (3.0 +/- 0.1 vs 2.5 +/- 0.2 ml/min/ kg; P = .01) and SCr concentration (1.8 +/- 0.1 vs 1.5 +/- 0.1 mg/dL; P = .03) than did non-Greyhound dogs, but the serum urea nitrogen (SUN) concentration was not significantly different (18 +/- 1 vs 18 +/- 2 mg/dL; P = .8). Therefore, the higher SCr concentration in Greyhounds is not attributable to decreased GFR, and may be associated with the high muscle mass in the breed. Healthy Greyhounds have higher GFR than do non-Greyhound dogs.     

Comparison of signalment, clinicopathologic findings, histologic diagnosis, and prognosis in dogs with glomerular disease with or without nephrotic syndrome

Background: Nephrotic syndrome (NS) develops most commonly in people with glomerular diseases associated with marked albuminuria. Hypernatremia, hypertension, and progressive renal failure are more prevalent in nephrotic than nonnephrotic human patients. Hypothesis/Objectives: Dogs with NS have higher serum cholesterol, triglyceride, and sodium concentrations, higher urine protein:creatinine ratios (UPC) and systolic blood pressure, and lower serum albumin concentrations than dogs with nonnephrotic glomerular disease (NNGD). NS is associated with membranous glomerulopathy and amyloidosis. Affected dogs are more likely to be azotemic and have shorter survival times. Animals: Two hundred and thirty‐four pet dogs (78 NS dogs, 156 NNGD dogs). Methods: Multicenter retrospective case‐control study comparing time‐matched NS and NNGD dogs. NS was defined as the concurrent presence of hypoalbuminemia, hypercholesterolemia, proteinuria, and extravascular fluid accumulation. Signalment, clinicopathologic variables, histopathologic diagnoses, and survival time were compared between groups. Results: Age, serum albumin, chloride, calcium, phosphate, creatinine, and cholesterol concentrations, and UPC differed significantly between NS and NNGD dogs. Both groups were equally likely to be azotemic at time of diagnosis, and NS was not associated with histologic diagnosis. Median survival was significantly shorter for NS (12.5 days) versus NNGD dogs (104.5 days). When subgrouped based on serum creatinine (< or ≥1.5 mg/dL), survival of NS versus NNGD dogs was only significantly different in nonazotemic dogs (51 versus 605 days, respectively). Conclusions and Clinical Importance: Presence of NS is associated with poorer prognosis in dogs with nonazotemic glomerular disease. Preventing development of NS is warranted; however, specific interventions were not evaluated in this study.     

Glomerular Filtration Rate and Renal Volume in Dogs with Congenital Portosystemic Vascular Anomalies before and after Surgical Ligation

Glomerular filtration rate (GFR) and renal volume were evaluated in dogs with confirmed portosystemic vascular anomalies (PSVA) before and after surgical ligation of their PSVA. Pre- and postligation CBC, serum biochemistry, urinalysis, abdominal ultrasonography with measurement of renal volume, and per rectal scintigraphy were performed to document resolution of abnormalities consistent with portosystemic shunting. GFR was estimated by plasma 99mTc-diethylenetriaminepentaacetic acid (99mTc-DTPA) clearance before (n = 21) and after (n = 12) surgical correction of PSVA. Preligation 99mTc-DTPA GFR was increased (median, 5.64 mL/minute/kg; range, 3.53-8.49 mL/minute/kg; reference range, 2.83-4.47 mL/minute/kg) in 81% (17/21) of dogs. Postligation 99mTc-DTPA GFR decreased in all 12 evaluated dogs (median change = -42%; P < .001). Preligation renal volume was above the reference range for the left and right kidneys in 71% (10/14) and 69% (11/16) of dogs evaluated, respectively. Right renal volume decreased significantly (n = 5; median change, -45%; P = .03) after surgical ligation of PSVA. These findings document increased GFR and renal volume in dogs with PSVA, which may explain in part the low blood urea nitrogen and serum creatinine concentrations encountered in these dogs. Knowledge of changes in GFR associated with PSVA ligation may prove helpful in the anesthetic, drug, and dietary management of affected dogs.