Evaluation of prognostic factors, survival rates, and treatment protocols for immune-mediated hemolytic anemia in dogs: 151 cases (1993-2002)

Methylprednisolone alone or combined with cyclosporine or mycophenolate mofetil for the treatment of immune-mediated hemolytic anemia in dogs, a prospective study

BACKGROUND

Benefit of adding a second-line immunosuppressive drug to glucocorticoids for the treatment of non-associative immune-mediated hemolytic anemia (naIMHA) in dogs has not been defined prospectively.

HYPOTHESIS/OBJECTIVES

Evaluate the effectiveness of different immunosuppressive protocols in naIMHA dogs.

ANIMALS

Forty-three client-owned dogs.

METHODS

Open label, randomized, clinical trial. Dogs were treated with methylprednisolone (M-group), methylprednisolone plus cyclosporine (MC-group) or methylprednisolone plus mycophenolate mofetil (MM-group). Dogs were defined as responders by disappearance of signs of immune-mediated destruction and hematocrit stabilization. Frequency of responders was compared between M-group and combined protocols (MC and MM-group evaluated together), and among the 3 different therapeutic groups at 14 (T14), 30 (T30), 60 (T60) days after admission. Frequency of complications, length of hospitalization and relapse were also compared. Death rate was evaluated at discharge, T60 and 365 (T365) days.

RESULTS

Proportion of responders was not significantly different between M-group and combined protocols (MC and MM-groups), nor among the 3 therapeutic groups at T14, T30, and T60 (P > .17). Frequency of relapse, complications, and length of hospitalization were not significantly different between M-group and dogs treated with combined protocols, nor among the 3 treatment groups (P > .22). Death was significantly more common only for MM-group compared with MC-group at T60 (+42.8%; 95% CI: 11.5-67.4; P = .009), and at T365 (+50%; 95% CI: 17.5-73.2; P = .003).

CONCLUSIONS AND CLINICAL IMPORTANCE

Combined immunosuppressive therapy did not improve hematological response in naIMHA.

Comparison of timing of relapse in dogs with nonassociative immune-mediated hemolytic anemia, thrombocytopenia, or polyarthritis

BACKGROUND

Relapse is a clinical concern in dogs diagnosed with immune-mediated hemolytic anemia (IMHA), thrombocytopenia (ITP), or polyarthritis (IMPA). The average time to relapse is unknown, and evidence that vaccination is associated with disease relapse is lacking.

HYPOTHESIS/OBJECTIVES

Compare the incidence of relapse in groups of dogs with IMHA, ITP, or IMPA over a 24-month period after diagnosis and compare proportions of dogs that received vaccines in those dogs that did and did not relapse.

ANIMALS

One hundred sixty client-owned dogs (73 with IMHA, 55 with ITP, 32 with IMPA).

METHODS

Medical records of dogs were reviewed with the goal of following cases for a minimum of 2 years. Incidence of relapse was calculated for each disease, and relapse rates in dogs that were or were not vaccinated after diagnosis were compared.

RESULTS

Relapse rates at 12 months differed significantly among disease groups (P = .02), with a higher rate for IMPA (35%) compared to IMHA (11%) or ITP (11%). Relapse rate at 24 months was 41% for IMPA, 18% for IMHA, and 23% for ITP. Ninety percent of IMPA relapses occurred in the first 12 months after diagnosis, compared with 56% for IMHA and 50% for ITP. Vaccine administration after diagnosis was not associated with relapse (P = .78).

CONCLUSIONS AND CLINICAL IMPORTANCE

Risk of disease relapse in IMPA is highest in the first year after diagnosis, with a higher relapse rate compared with IMHA and ITP. The role of vaccination in disease relapse remains unclear.

Immune-Mediated Hemolytic Anemia and Clinically Suspected Acute Pancreatitis in Dogs, a Pilot Study

Acute pancreatitis can be a complication of massive hemolysis, above all when intravascular in nature. Therefore, the aim of this study was to investigate the association between canine immune mediated hemolytic anemia (IMHA) and clinically suspected acute pancreatitis (CSAP) and the role of calculated free plasma hemoglobin (Hbfp) in CSAP occurrence/development. In this cohort study the records of 95 dogs with IMHA and 95 sick dogs with pathologies other than IMHA were compared for CSAP occurrence/development. At presentation, 12/95 dogs with IMHA met criteria for CSAP, while only 3/95 sick control dogs met these criteria (χ2 =1.58, P = .008). Within 7 days of hospitalization 9 additional dogs with IMHA had developed CSAP. The Hbfp was calculated and compared for dogs with IMHA that had/developed CSAP and for those without CSAP. In dogs with IMHA, a calculated Hbfp concentration ≥ 0.08 g/dL resulted in an increased relative risk (RR) of having/developing CSAP (RR = 2.54, 95% CI, 1.51-4.29; P = .003). No significant effect on short-term prognosis in dogs with IMHA was found between those having/developing CSAP and those without CSAP. This study showed that dogs with IMHA have an increased risk of having CSAP and Hbfp concentration may be involved in the pathogenesis of acute pancreatitis.

The Indirect Antiglobulin (Coombs') Test Is Specific but Less Sensitive Than the Direct Antiglobulin Test for Detecting Anti-Erythrocytic Autoantibodies and Thereby Immune-Mediated Hemolytic Anemia in Dogs

The immunodiagnostic assessment of dogs suspected of having immune-mediated hemolytic anemia (IMHA) is based on persistent autoagglutination of erythrocytes (after three saline washes), marked spherocytosis, and a positive direct antiglobulin (Coombs') test (DAT). However, the value of using the indirect antiglobulin test (IAT) for the detection of anti-erythrocytic autoantibodies in serum from dogs suspected of having IMHA is unclear. To evaluate the IAT, leftover serum samples from a large cohort of 94 dogs suspected of having IMHA and for which DAT results were known were incubated with DAT- erythrocytes, and five IAT techniques were performed (in part with different reagents and temperatures): microtiter plate (MICRO), microcapillary, laboratory gel column, gel minitube kit (GEL KIT), and immunochromatographic strip kit. Two IAT techniques (MICRO at 37 °C and GEL KIT with rabbit anti-dog polyvalent reagent) detected autoantibodies against erythrocytes in serum from 53% and 57% of DAT+ dogs, respectively, while other IATs performed less well. Moreover, while the analytic specificity of the IAT methods compared to the DAT ranged from 96-100%, the sensitivity range was only 9-57%. Thus, we still recommend DAT for diagnosis and monitoring of IMHA in dogs but conclude that a positive IAT result may aid diagnostically when serum is available, but fresh red blood cells are not.

Cytokine Adsorption as an Adjunctive Treatment for Patients with Immune-Mediated Hemolytic Anemia Receiving Therapeutic Plasma Exchange: A Case Series of 3 Dogs

The use of cytokine adsorption is an emerging treatment for inflammatory diseases in human medicine. There are few reports of this treatment modality in veterinary medicine and no reports of the use of a cytokine adsorbent for immune-mediated hemolytic anemia (IMHA). These case reports illustrate the use of a cytokine adsorbent as an adjunctive treatment during therapeutic plasma exchange (TPE). All dogs were unresponsive to conventional treatment or were severely affected by rapid hemolysis of red blood cells. The aim was to treat all dogs with three sequential TPE sessions; however, one dog died before completion of three sessions and one dog required additional sessions. Preliminary evidence indicates that the use of a cytokine adsorption is well tolerated and can be considered as an adjunct in the management of IMHA that is severe or refractory to traditional treatment.

Demography and disorders of English Cocker Spaniels under primary veterinary care in the UK

BACKGROUND

The English Cocker Spaniel (ECS) is a common family dog in the UK. This study aimed to describe demography, morbidity, and mortality in ECS under primary veterinary care in the UK during 2016 using data from the VetCompass™ Programme. This study hypothesised that the prevalence of aggression is higher in male than female ECS, and higher in solid-coloured than bi-coloured ECS.

RESULTS

English Cocker Spaniels comprised 10,313/336,865 (3.06%) of dogs under primary veterinary care during 2016. The median age was 4.57 years (inter-quartile range (IQR) 2.25-8.01) and the median adult bodyweight was 15.05 kg (IQR 13.12-17.35). The annual proportional birth rate was relatively stable between 2.97-3.51% from 2005-2016. The most common specific diagnoses were periodontal disease (n = 486, prevalence 20.97%, 95% confidence interval (CI): 19.31-22.62), otitis externa (n = 234, 10.09%, 95% CI: 8.87-11.32), obesity (n = 229, 9.88%, 95% CI: 8.66-11.09), anal sac impaction (n = 187, 8.07%, 95% CI: 6.96-9.18), diarrhoea (n = 113, 4.87%, 95% CI: 4.00-5.75), and aggression (n = 93, 4.01%, 95% CI: 3.21-4.81). The prevalence of aggression was higher in males (4.95%) than in females (2.87%) (P = 0.015) and in solid-coloured (7.00%) than in bi-coloured dogs (3.66%) (P = 0.010). The median age at death was 11.44 years (IQR 9.46-13.47) and the most common grouped causes of death were neoplasia (n = 10, 9.26%, 95% CI: 3.79-14.73), mass-associated disorders (n = 9, 8.33%, 95% CI: 4.45-15.08), and collapse (n = 8, 7.41%, 95% CI: 3.80-13.94).

CONCLUSIONS

Periodontal disease, otitis externa, and obesity are identified as the most common health issues for ECS, and neoplasia and mass-associated disorders as the most common reasons for death. The prevalence of aggression was higher in males and solid-coloured dogs. The results can aid veterinarians in giving evidence-based health and breed choice information to dog owners and highlights the importance of thorough oral examination and body condition score evaluation during routine veterinary examination of ECS.

Point-of-care global coagulation assay parameters in normal dogs and dogs with primary immune-mediated hemolytic anemia

OBJECTIVE

To compare viscoelastic parameters between healthy control dogs and dogs with primary immune-mediated hemolytic anemia (pIMHA) using a new, point-of-care viscoelastic coagulation monitor (VCM).^a DESIGN: Retrospective study from 2017 to 2021.

SETTING

Three regional private referral centers.

ANIMALS

Eighteen client-owned dogs with pIMHA and 33 healthy control dogs. pIMHA dogs were defined based on established criteria.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Medical records of dogs with pIMHA and VCM performed at diagnosis from 2017 to 2021 and apparently healthy control dogs voluntarily enrolled in the blood donor program from 2017 to 2018 were reviewed. For the healthy control dogs, consent was obtained to perform VCM in addition to traditional screening. Compared to healthy control dogs, dogs with pIMHA had mean VCM parameters consistent with hypercoagulability, demonstrated by lower mean (SD) clot formation time (108 s [30] vs 233 s [55]; P < 0.0001), higher mean alpha angle (62 degrees [6] vs 52 degrees [6]; P < 0.0001), higher mean maximum clot formation (49 VCM units [11] vs 32 VCM units [5]; P < 0.0001), higher mean amplitude at 10 minutes (40 VCM units [11] vs 19 VCM units [3]; P < 0.0001), and higher mean amplitude at 20 minutes (47 VCM units [11] vs 25 VCM units [4]; P < 0.0001). pIMHA dogs also had significantly higher median (interquartile range) lysis index at 30 minutes (100% [100-100] vs 98% [90-100]; P < 0.0001). When compared to 3 established normal canine reference intervals, dogs with pIMHA had a significantly higher proportion of VCM variables (48%-57%) consistent with hypercoagulability, and a significant percentage of pIMHA dogs (78%-89%) had VCM tracings consistent with hypercoagulability overall, irrespective of the interval utilized for interpretation.

CONCLUSIONS

This study demonstrates hypercoagulability in dogs with pIMHA when compared to healthy control dogs using VCM. Prospective evaluation is warranted to further characterize these findings as well as to evaluate their clinical impact.

Clinical findings and assessment of factors associated with survival in dogs presenting with hyperbilirubinaemia: 115 cases in Victoria, Australia (2015–2020)

Introduction

Hyperbilirubinaemia is an important clinicopathological finding in canine medicine. The objectives of this study were to describe the clinical presentation and outcome of dogs with hyperbilirubinaemia; also to identify factors associated with survival.

Materials and methods

Retrospective study of dogs with hyperbilirubinaemia from two referral centres in South Australia (2015–2020). Signalment, clinical signs, clinicopathological data, diagnosis and outcome were obtained from searching clinical records. Univariable analysis and logistic regression modelling were used to compare outcomes and overall survival.

Results

A total of 115 cases were included. The most common clinical signs were vomiting (63.5%), anorexia (62.6%), lethargy (55.7%) and pyrexia (18.3%). Pre‐hepatic icterus was diagnosed in 18 cases (15.7%), hepatic icterus in 51 cases (44.3%) and post‐hepatic icterus in 42 cases (36.5%). The median survival time across all cases was 40 days (95% confidence interval [CI]: 9–126 days). There was an increased risk of death in dogs with serum bilirubin greater than 60 μmol/L at diagnosis (odds ratio [OR] = 3.55; 95% CI: 1.53–8.22; p‐value = 0.003) and in dogs with pre‐hepatic icterus compared to hepatic (OR = 4.35; 95% CI: 1.18–16.0; p‐value = 0.027) and post‐hepatic icterus (OR = 6.52; 95% CI: 1.67–25.5; p‐value = 0.007).

Conclusions

Pre‐hepatic icterus was associated with a significantly higher risk of death than hepatic and post‐hepatic icterus. Serum bilirubin >60 μmol/L at diagnosis was associated with a significantly shorter median survival time. This cut‐off may be useful in discussions with owners regarding pursuing further diagnostic investigation and treatment. Further prospective studies are needed to prove the validity of this cut‐off.

Effectiveness of aspirin vs. clopidogrel in dogs with immune mediated haemolytic anaemia evaluated by serial thromboelastography and platelet mapping

Most dogs with immune mediated haemolytic anaemia (IMHA) are hypercoagulable, as measured by thromboelastography (TEG). Thromboelastography-platelet mapping (TEG-PM) has been used to assess platelet function in human patients treated with aspirin or clopidogrel. The aim of this study was to compare platelet thromboxane A₂-receptor inhibition (TXA_2-RI) and platelet adenosine diphosphate (ADP)-receptor inhibition (ADP-RI) as measured by TEG-PM in dogs with primary IMHA receiving aspirin or clopidogrel to determine if TEG-PM might be useful to monitor treatment. Eighteen client-owned dogs with IMHA were enroled in a prospective double blinded study. Dogs were randomised to receive aspirin or clopidogrel in addition to standard therapy. Thromboelastography was measured before, and 1 and 4 days after commencing treatment. Thromboelastography-PM was performed on days 1 and 4. Non-responders were defined as < 50 % platelet thromboxane A₂-receptor inhibition (TXA_2-RI) in the aspirin group and < 50 % platelet adenosine diphosphate (ADP)-receptor inhibition (ADP-RI) in the clopidogrel group, on day 4. Mean platelet TXA₂-RI and platelet ADP-RI were not significantly different between groups at any timepoint (P > 0.05). The overall mean percentage inhibition of TXA₂-receptor was 25 % (aspirin 33 %, clopidogrel 15 %), and of ADP-receptor was 82 % (aspirin 83 %, clopidogrel 80 %). On day 4, 6/9 dogs (66 %) in the aspirin group and 2/8 dogs (25 %) in the clopidogrel group were non-responders (P = 0.086). Two dogs defined as responders based on TEG-PM developed thromboembolism. Overall, there was no significant difference in efficacy between aspirin and clopidogrel based on measurement of receptor inhibition using TEG-PM (P > 0.05), and routine TEG was not reliable for monitoring treatment response in dogs with IMHA. In some dogs, there was a discrepancy between TEG-PM results and clinical response. Further investigation of TEG-PM use in dogs, including its usefulness to monitor treatment response and adjust treatment in individual dogs and any effect of anaemia, is warranted.

Pulmonary thromboembolism due to immune-mediated hemolytic anemia in a cat: A serial study of hematology and echocardiographic findings

Pulmonary thromboembolism (PTE) secondary to immune-mediated hemolytic anemia (IMHA) is rarely diagnosed in cats. In this report, a 3-year-old cat was referred to our private hospital with dyspnea, anorexia, and anemia. On the thoracic radiography, cardiac enlargement and pulmonary edema were noted. Echocardiography revealed right ventricular and right atrium enlargement with mild tricuspid regurgitation (tricuspid regurgitation velocity 3.28 m/s). A thrombus was recognized in the main pulmonary artery on the right parasternal short-axis view. Blood examination suggested regenerative anemia and autoagglutination. The findings suggested immune-mediated hemolytic anemia and PTE. Antithrombotic therapy (dalteparin) and immunosuppressive therapy (prednisolone) were administered under oxygen supplementation in the ICU cage. After treatment, regenerative anemia and right-heart failure were improved. During follow-up, the cat remained hemodynamically stable, and the owner reported no cardiac-related clinical signs. Further blood examination confirmed the anemia was improved. Prednisolone was discontinued on Day 56, and the cat continues in good health, administered only mycophenolate mofetil. The clinical outcome of PTE secondary to the IMHA throughout 100 days of periodical observation was reported.

Splenectomy in the management of primary immune-mediated hemolytic anemia and primary immune-mediated thrombocytopenia in dogs

Background

Current reports about the use of splenectomy for the management of immune‐mediated hemolytic anemia (IMHA) or immune‐mediated thrombocytopenia (ITP) or both in dogs are limited.

Objectives

To retrospectively describe the use of splenectomy as part of the management for IMHA, ITP, and concurrent IMHA and severe thrombocytopenia (CIST) in dogs. It was hypothesized that splenectomy would be beneficial in allowing for reduction of dose of immunosuppressive drugs or discontinuation in 1 or more of these groups.

Animals

Seventeen client‐owned dogs (7 with IMHA, 7 with ITP, and 3 with CIST) were identified across 7 UK‐based referral hospitals from a study period of 2005 to 2016.

Methods

Data were collected retrospectively via questionnaires and included information about diagnosis, management and treatment response before and after splenectomy. Based on clinical outcome, treatment with splenectomy as part of the management protocol was classified as either successful or unsuccessful.

Results

Six of 7 dogs with ITP were managed successfully with splenectomy as part of their management protocol (3 complete and 3 partial responses), although 1 subsequently developed suspected IMHA. Of the 7 dogs with IMHA, splenectomy was part of a successful management protocol in 4 dogs (2 complete and 2 partial responses). In the CIST group, 1 case (1/3) responded completely to management with splenectomy as part of the management protocol.

Conclusions and Clinical Importance

Splenectomy was considered successful and well tolerated in most cases of isolated ITP. Whether there is a benefit of splenectomy in cases of IMHA and CIST could not be determined in the current study.

Retrospective evaluation of systemic hypertension in dogs with nonassociative (primary) immune-mediated hemolytic anemia (December 2016 to April 2019): 26 cases

OBJECTIVE

To report the prevalence of arterial hypertension in a population of dogs with nonassociative immune-mediated hemolytic anemia (IMHA) on presentation and during hospitalization. To determine the relationships of systolic blood pressure (SBP) with mortality and a prognostic indicator, the canine hemolytic anemia objective score.

DESIGN

Retrospective observational study (December 2016 to April 2019).

SETTING

University teaching hospital.

ANIMALS

Twenty-six clinical dogs presenting to the ICU with nonassociative (primary) IMHA and a control group of 23 clinical dogs with idiopathic epilepsy hospitalized in the ICU for seizure treatment or monitoring.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Hypertension was defined as SBP ≥ 160 mm Hg and severe hypertension as SBP ≥ 180 mm Hg. Mean SBP was significantly increased in IMHA dogs (161 mm Hg, SD = 21) compared to ICU control dogs (138 mm Hg, SD = 14; P < 0.005). Hypertension was present in 13 of 26 (50.0%) dogs across the period of hospitalization and was severe in three of 26 (11.5%). During at least 1 day of hospitalization, 18 of 26 (69.2%) dogs were hypertensive and eight of 26 (34.6%) were severely hypertensive. Hypertension was not associated with short-term mortality or canine hemolytic anemia objective score.

CONCLUSIONS

In this retrospective study, hypertension was more prevalent in dogs with nonassociative IMHA than a control population of ICU-hospitalized dogs. An association between autoimmune conditions and hypertension has been previously reported in people but not within a canine population. Hypertension in dogs may have an inflammatory or autoimmune etiology. SBP should be monitored closely in canine IMHA, in case antihypertensive treatment is required.

Urinary 11-dehydrothromboxane B2 concentrations in 20 dogs with primary immune-mediated hemolytic anemia

BACKGROUND

Thromboembolic disease is a major cause of mortality in dogs with immune-mediated hemolytic anemia (IMHA). At present, no reliable biomarkers of individual patient thrombotic risk are available. In human medicine, increased urinary thromboxane concentrations have utility as markers of prothrombotic tendency in various situations.

HYPOTHESIS/OBJECTIVES

First, to determine if urinary 11-dehydrothromboxane B2 (u11-dTXB) concentrations are increased in dogs with primary IMHA compared to normal dogs; second, to assess whether u11-dTXB concentration is associated with survival, known prognostic indicators, or frequency of thrombosis in dogs with IMHA.

ANIMALS

Twenty client-owned dogs diagnosed with primary IMHA and 17 healthy dogs volunteered by hospital staff.

METHODS

Prospective case-control study. A previously validated ELISA was used to measure urine 11-dTXB concentrations, which were normalized to urine creatinine concentration (u11-dTXB:Cr). Samples were obtained at presentation from patients with primary IMHA. Standard clincopathological data at baseline and survival data were collected. Urinary 11-dTXB:Cr was compared between outcome subgroups, and correlated with known markers of disease severity.

RESULTS

Baseline u11-dTXB:Cr was significantly higher in dogs with IMHA than in healthy dogs (median, 3.75; range, 0.83-25.36 vs 0.65; 0.24-2.57; P = .003) but did not differ between dogs with IMHA that survived and did not survive to 30 days after presentation, nor between dogs with and without clinical suspicion of thrombotic disease.

CONCLUSIONS AND CLINICAL IMPORTANCE

Urinary 11-dTXB:Cr is increased in dogs with IMHA compared to healthy controls, consistent with a prothrombotic state. However, in this IMHA population u11-dTXB:Cr was not associated with survival or suspected thrombosis.

Pharmacokinetics, pharmacodynamics and safety evaluation of 5,5'-methylenebis(2-acetoxybenzoic acid) in dogs following intravenous administration

Complement-mediated intravascular hemolysis occurs in canine immune-mediated hemolytic anemia (IMHA). Complement inhibitors might enhance treatment of this disease. Dimers of acetylsalicylic acid such as 5,5'-methylenebis(2-acetoxybenzoic acid) (DAS) have been reported to inhibit complement. This study aimed to characterize the pharmacokinetics and safety profile of a single 3 mg/kg IV dose of DAS in 6 healthy mixed-breed dogs. Serum concentrations of DAS and its primary metabolites were measured by liquid chromatography-tandem mass spectrometry at baseline and at 5, 10 and 30 min, and 1, 2, 4, 6, 8, 12, 18 and 24 h post-administration. Additional blood samples were collected 7 and 14 days after drug administration. Complete blood counts, serum chemistry panels, C-reactive protein measurements, coagulation testing and cytokine analyses were used for safety monitoring. Following IV administration of 3 mg/kg DAS, the estimated mean maximum plasma concentration was 54,709 ng/mL. Pharmacokinetic modeling suggested that DAS was eliminated with a half-life value of 8.1 h, equivalent to a clearance of 6.93 L/hr kg and a volume of distribution of 56 mL/kg. Plasma concentrations of the metabolites were measured rapidly (within 15-60 min for M1 and M2 respectively). Overall, the relative exposure to M1 and M2 suggest significant biotransformation of DAS occurred, but DAS was the most abundant circulating species. No adverse clinical reactions were noted following DAS administration and safety studies suggested DAS caused no inflammatory response or coagulation disturbance. Further clinical evaluation of DAS is warranted.

Comparative study of immunohematological tests with canine blood samples submitted for a direct antiglobulin (Coombs') test

BACKGROUND

A 2019 ACVIM consensus statement on diagnostics for immune-mediated hemolytic anemia (IMHA) in dogs made testing recommendations. As data on the performance of immunohematological tests was lacking, we undertook a comparative analysis.

MATERIAL AND METHODS

Anticoagulated blood samples from 126 dogs suspected of having IMHA submitted to a diagnostic veterinary laboratory for a routine direct antiglobulin test (DAT) and from 28 healthy control dogs were evaluated for spherocytosis and autoagglutination before and after three saline washes. Samples were also subjected to different DATs: a gel minitube and an immunochromatographic strip kit used in clinics; neutral gel column cards, microtiter plates (at 4°, 22°, and 37°C), capillary tubes, and flow cytometry used in laboratories.

RESULTS

Samples from healthy dogs yielded negative results with all immunodiagnostic tests. Among the 126 samples submitted for DAT 67 were positive by a DAT utilizing microtiter plates with goat anti-dog antiglobulin DAT at 22°C. Notably, DAT results were comparable and consistent across all evaluated methods regardless of antiglobulin and temperature used. DAT+ dogs were more severely anemic and more likely to have erythroid regeneration compared to DAT- dogs. Macroscopic agglutination in tubes or on slides was observed in 48 samples after 1:1 and 1:4 blood to saline dilution, but only persisted in four samples after washing. Among the DAT+ samples, 57% had agglutination, 87% had spherocytosis, and 45% had both. There was good correlation between spherocytosis and DAT results from the six DAT techniques, but the correlation with autoagglutination was only fair. Clinical follow-up was available for 42 dogs. Of the sample from 12 DAT+ dogs collected during treatment, 10 remained DAT+ when tested 1-24 weeks after initial assessment.

CONCLUSIONS

Based upon this comparative prospective survey, all in-clinic and laboratory DAT techniques produced similar results when performed by trained personnel and can therefore be recommended for detection of antibody-coated erythrocytes and immunohematological diagnosis. In addition, use of these tests for monitoring response of IMHA dogs to treatment might be valuable.

Anticoagulant profile of subcutaneous enoxaparin in healthy dogs

Our study objective was to identify a subcutaneous enoxaparin dosage that provided a consistent anticoagulant intensity in dogs. Our hypotheses were that a dose of 0.8 mg/kg would provide inconsistent anticoagulation, a higher dose would provide consistent anticoagulation over a greater duration of time, and viscoelastometry would effectively monitor the anticoagulant status. Six healthy dogs received two subcutaneous enoxaparin doses (0.8 and 2 mg/kg) for anti-Xa activity determinations and pharmacokinetic modeling. Based on calculations derived from these results, 1.3 mg/kg, SC, q8 h was administered for seven doses. Target ranges for anticoagulant intensity were defined as anti-Xa activity of 0.5-1 U/ml, and change from baseline of two viscoelastometric parameters: activated clotting time (ΔACT; ≥40 s), and clot rate (CRpost; ≤20 U/min). Following an initial injection at 1.3 mg/kg, anti-Xa activity of 5/6 dogs reached or exceeded the target range. Following the final dose, anti-Xa activity reached or exceeded the target range in all dogs, and ΔACT and CRpost values exceeded target for 2-6 and 4-12 h, respectively. At an enoxaparin dosage of 1.3 mg/kg, SC, q8 h, anti-Xa activity was consistently above the minimum threshold of the target range; however, the safety of this dosage remains to be determined.

Low serum folate concentrations in dogs with non-associative immune-mediated haemolytic anaemia

BACKGROUND

Folate deficiency in people can occur in conditions causing increased demand, including haemolytic anaemia. This has not been investigated in dogs with non-associative immune-mediated haemolytic anaemia (IMHA).

METHODS

Cohort study of 15 dogs with non-associative IMHA. Haematocrit (HCT) and serum folate concentrations were measured at presentation and each subsequent venipuncture performed for monitoring. The relationship between serum folate concentrations and HCT was investigated using linear and logistic mixed-effects regression models and in paired samples using a one-tailed paired t-test.

RESULTS

Low serum folate concentrations occurred in five of 15 dogs. In 126 samples, a significant positive relationship was found between HCT and corresponding serum folate concentrations. A significant relationship was found between dichotomised folate concentrations (below the reference interval or within/above the reference interval) and HCT and between serum folate concentrations and dichotomised HCT (less than or equal/above 0.30 L/L). For paired samples (available in eight dogs), the mean serum folate concentration of samples with the lowest HCT was significantly lower than that of samples in which the HCT first exceeded 0.30 L/L.

CONCLUSIONS

Low serum folate concentrations were observed in some dogs with non-associative IMHA. Further studies are needed to determine the cause and investigate whether folate supplementation would be beneficial.

Cross-sectional study of approaches to diagnosis and management of dogs with immune-mediated haemolytic anaemia in primary care and referral veterinary practices in the United Kingdom

Objectives

To determine whether veterinarians in primary care practices (PCPs) and board-certified clinicians (BCCs) approach treatment of dogs with immune-mediated haemolytic anaemia (IMHA) similarly, and whether practitioners with more experience treat similarly to those with less experience. We hypothesised those in PCPs would show more variation in their approach to similar cases than BCCs.

Methods

A cross-sectional study was conducted by distributing a questionnaire to BCCs and veterinarians in PCPs. The questionnaire included direct questions and a number of clinical scenarios intended to capture approaches to common treatment problems.

Results

Questionnaire responses were received from 241 veterinarians, including 216 in PCPs and 25 BCCs. Veterinarians in both settings used similar tests for diagnosis of IMHA, but BCCs performed more tests to exclude underlying causes of ‘associative’ disease. All veterinarians reported use of similar initial dosages of glucocorticoids (median 2 mg/kg per day in both groups, p = 0.92) but those used by more experienced practitioners were higher than those with less experience. Most veterinarians made allowances for the weight of dogs, using lower prednisolone dosages in a clinical scenario involving a 40 kg dog compared to a 9 kg dog (p = 0.025 for PCP, p = 0.002 for BCC). BCCs reported greater use of combinations of immunosuppressive drugs (p<0.0001) and of antithrombotic drugs (p<0.0001); use of antithrombotic drugs was also less common among more experienced practitioners compared to less experienced.

Conclusions

Approaches to treatment of dogs with IMHA differ between BCCs and those in PCP. These differences may affect design and implementation of future research studies and clinical guidelines.

[Prevention of canine parvovirosis - Part 3: Vaccine-associated adverse events]

Although nowadays vaccines, especially those against canine parvovirus (CPV), are considered to be safe, vaccine-associated adverse events (VAAEs) can occur in rare cases. Some VAAEs are mild and manifest shortly (within a few days) after vaccination (e. g. gastrointestinal signs, fever, reduced general condition, lymphadenopathy). These signs are likely a result of vaccine virus replication and indicate a good immune response. Anaphylactic reactions can also occur promptly following vaccine administration and might be life threatening. Affected dogs show clinical signs such as edema, salivation, vomiting, diarrhea, hypotension, and/or shock. Since it is often unclear which component of the vaccine carries responsibility for the anaphylactic reaction it is important to limit future vaccinations of these dogs to indispensable components only. When revaccination is unavoidable, e. g. because antibodies against CPV cannot be detected, combined vaccines should not be used and CPV (and other components, if needed) should preferably be vaccinated separately. Changing the vaccine manufacturer might also prevent further anaphylactic reactions. Finally, there are VAAEs occurring after a prolonged period of time. In dogs, it is discussed that autoimmune diseases, such as immune-mediated hemolytic anemia (IMHA), can be a consequence of excessive vaccination or in the least be triggered by vaccination. Numerous dogs with IMHA are reported to have a history of receiving a vaccination within a few weeks before the onset of clinical sings. In such dogs, further vaccinations should generally be avoided.

Dexamethasone Can Be Safely and Effectively Used for Treatment of Masticatory Muscle Myositis in Dogs

Dexamethasone is the glucocorticoid of choice in many human inflammatory and immune-mediated conditions, given its reported effectiveness and limited side effect profile. In veterinary medicine, the glucocorticoid of choice is prednisone, however the safety of longer-term use of dexamethasone has not previously been studied. The aim of this study was to evaluate the safety, effectiveness and side effects of dexamethasone use as the glucocorticoid treatment for masticatory muscle myositis in dogs - an immune-mediated inflammatory condition. 93% of dogs showed a clinical improvement within two weeks of treatment, and 100% by ten weeks. 35% of dogs showed adverse reactions, however these were all mild and resolved with tapering of the dexamethasone dose. In conclusion, dexamethasone can be safely and effectively used for the treatment of masticatory muscle myositis in dogs, and should be considered for use in these cases, either alone or alongside additional immunosuppressive medications. Side effects are mild and resolve with tapering of the dexamethasone dose.

Thrombotic Complications in Patients with Immune-Mediated Hemolysis

Autoimmune hemolytic anemias are rare and heterogeneous disorders characterized by hemolysis, which is a well-recognized risk factor for thrombosis. The most common immune-mediated anemias are represented by autoimmune hemolytic anemia and paroxysmal nocturnal hemoglobinuria, both associated with a high rate of thrombosis. Multiple pathophysiological mechanisms for thrombosis have been proposed, involving hemolysis itself and additional effects of the immune system. Despite the increasing awareness of the thrombotic risk in these conditions, evidence-based guidance on prevention and management of thrombotic events is lacking. We herein report available evidence on epidemiological data on thrombosis and thrombophilia in immune-mediated hemolysis, together with possible underlying pathophysiological mechanisms. In addition, we summarize current recommendations for treatment of thrombosis in immune-mediated hemolysis. In particular, we address the issue of thrombotic complications treatment and prophylaxis by proposing a therapeutic algorithm, focusing on specific situations such as splenectomy and pregnancy.

Breed predispositions, clinical findings, and prognostic factors for death in dogs with nonregenerative immune-mediated anemia

BACKGROUND

Breed predispositions, survival, and prognostic factors have not been evaluated in dogs with nonregenerative immune-mediated anemia (nrIMA).

HYPOTHESIS/OBJECTIVES

To describe clinicopathologic variables, evaluate their associations with survival, and determine breed predispositions for dogs with nrIMA.

ANIMALS

Fifty-nine client-owned dogs with nrIMA.

METHODS

Referral hospital records were reviewed retrospectively for dogs with primary nrIMA (PCV ≤30%, corrected reticulocyte percentage (CR%) ≤1.0, bone marrow sampling with evidence of immune-mediated destruction, and underlying causes excluded). Breed predispositions were evaluated by calculation of odds ratios in a case control study; prognostic factors by logistic regression in a cohort study.

RESULTS

Fifty-nine dogs with nrIMA had a median PCV of 12% (interquartile range [IQR]: 10%-17%) and CR% 0.1 (0%-0.2%). At least ≥1 ACVIM IMHA diagnostic criteria were met by 35 dogs (59%). Whippets, Lurchers, and miniature Dachshunds were predisposed to nrIMA. Median survival time was 277 days (IQR: 37-1925), with 3- and 12-month survival rates 61% and 43%, respectively. Erythroid regeneration and remission were achieved by 88% and 62% of dogs, respectively. Corrected reticulocyte percentage >0.2 was associated with improved survival.

CONCLUSION AND CLINICAL IMPORTANCE

Although there is overlap of clinical features between dogs with IMHA and nrIMA, the prognosis for those with nrIMA depends predominantly on the severity of reticulocytopenia.

Serum interleukin 17 concentrations in dogs with immune-mediated hemolytic anemia

Background

Increased serum interleukin 17 (IL‐17) concentration has been associated with the immunopathogenesis of autoimmune hemolytic anemia in humans. No data are available about IL‐17 in immune‐mediated hemolytic anemia (IMHA) of dogs.

Objectives

Monitor changes in serum IL‐17 concentration during the acute stages of IMHA in dogs, compared with results in healthy dogs, and its relationship with outcome.

Animals

Thirty‐one client‐owned dogs with primary IMHA and 27 healthy dogs.

Methods

Quantification of serum IL‐17 concentration using a commercially available ELISA kit at the time of admission (D0), after 48 hours (D2) and after 96 hours (D4) as compared to concentration in healthy dogs. The IMHA dogs were classified as survivors if discharged from hospital, or nonsurvivors for any cause of in‐hospital mortality.

Results

Mean serum IL‐17 concentration was higher in dogs with IMHA on admission compared with healthy dogs (D0), but this difference was not significant (mean, 19.52 pg/mL vs 10.52 pg/mL, respectively, P = .17). Throughout hospitalization, serum IL‐17 concentration significantly decreased in survivors. Serum IL‐17 concentration at D0 was not different between survivors and nonsurvivors, but surviving dogs had significantly lower serum IL‐17 concentration at D2 and D4 (P = .04 and P = .004, respectively) compared with nonsurviving dogs. No correlation was found between serum IL‐17 concentration and serum total bilirubin or lactate concentrations or CBC parameters.

Conclusion and Clinical Importance

Serum IL‐17 concentration remained significantly higher in nonsurviving IMHA dogs whereas it significantly decreased during hospitalization in survivors, making serum IL‐17 concentration a potential biomarker for severity and response to treatment in IMHA.

Effect of dilution of canine blood samples on the specificity of saline agglutination tests for immune-mediated hemolysis

BACKGROUND

Saline agglutination tests (SATs) are widely recommended for diagnosis of immune-mediated hemolytic anemia in dogs, but there are frequent false-positive results.

OBJECTIVES

Specificity of SATs will improve at higher saline-to-blood ratios.

ANIMALS

One hundred fifty dogs treated at a veterinary referral hospital with hematocrits ≤30%.

METHODS

Prospective diagnostic accuracy study. Immune-mediated hemolysis (IMH) was considered present if a gel direct antiglobulin test (DAT) was positive and there was clinical evidence of hemolysis (n = 9), absent if another mechanism for anemia was identified and the DAT was negative or there was no hemolysis (n = 138), and if IMH status was unclear, dogs were excluded (n = 3). Saline agglutination tests were prepared at 1 : 1, 4 : 1, 9 : 1, and 49 : 1 saline-to-blood ratios, and microscopic agglutination was considered a positive result.

RESULTS

Specificity for IMH increased from 29% (95% confidence interval 20-38) at a 1 : 1 dilution to 97% (93-99) at a 49 : 1 dilution. Sensitivity was 88% (47-100) at 1 : 1 and 4 : 1 dilutions and 67% (30-93%) at 9 : 1 and 49 : 1 dilutions. Diagnostic accuracy increased from 33% (24-42) at 1 : 1 dilution to 95% (90-98) at 49 : 1 dilution.

CONCLUSIONS AND CLINICAL IMPORTANCE

If performed using a 49 : 1 saline-to-blood ratio, SATs achieve high specificity for IMH. Based on a gold standard of positive DAT and evidence of hemolysis, lower saline-to-blood ratio results should not be used because false-positive results are common.

RNA sequencing of whole blood in dogs with primary immune-mediated hemolytic anemia (IMHA) reveals novel insights into disease pathogenesis

Immune-mediated hemolytic anemia (IMHA) is a life-threatening autoimmune disorder characterized by a self-mediated attack on circulating red blood cells. The disease occurs naturally in both dogs and humans, but is significantly more prevalent in dogs. Because of its shared features across species, dogs offer a naturally occurring model for studying IMHA in people. In this study, we used RNA sequencing of whole blood from treatment-naïve dogs to study transcriptome-wide changes in gene expression in newly diagnosed animals compared to healthy controls. We found many overexpressed genes in pathways related to neutrophil function, coagulation, and hematopoiesis. In particular, the most highly overexpressed gene in cases was a phospholipase scramblase, which mediates the externalization of phosphatidylserine from the inner to the outer leaflet of cell membranes. This family of genes has been shown to be critically important for programmed cell death of erythrocytes as well as the initiation of the clotting cascade. Unexpectedly, we found marked underexpression of many genes related to lymphocyte function. We also identified groups of genes that are highly associated with the inflammatory response and red blood cell regeneration in affected dogs. We did not find any genes that distinguished dogs that lived vs. those that died at 30 days following diagnosis, nor did we find any relevant genomic signatures of microbial organisms in the blood of affected animals. Future studies are warranted to validate these findings and assess their implication in developing novel therapeutic approaches for dogs and humans with IMHA.

The utility of screening diagnostic tests in identifying associative immune-mediated haemolytic anaemia in dogs

The study aimed to (1) define the proportion of dogs with immune-mediated haemolytic anaemia (IMHA) that have associative and non-associative disease and (2) evaluate the utility of screening diagnostic tests in identifying potential triggers of associative IMHA. Medical records of 78 dogs diagnosed with IMHA at a specialist hospital in Sydney from July 2008 to August 2017 were reviewed. The original diagnosis was revised according to published guidelines (Garden et al., 2019) as either diagnostic, supportive or suspicious for IMHA. Associative IMHA was confirmed if immunosuppressive therapy was discontinued within six weeks of effective treatment of a potential trigger. Associative IMHA was considered possible when a potential trigger was identified but its significance could not be confirmed. Associative IMHA was confirmed (3) or suspected (7) in 10 dogs (13%, confidence interval [CI] 7.1%-22%), with 68 cases presumed to be non-associative. Associative IMHA was present in 3/29 (10.3%) of dogs with criteria diagnostic for IMHA, 4/42 (9.5%) of dogs with criteria supportive for IMHA and 3/7 (42.9%) of dogs with criteria suspicious for IMHA. Abdominal ultrasound was performed in 68 dogs and identified possible triggers in five (7.3%, CI 3.2% to 16%). Thoracic radiographs were performed in 70 dogs but did not identify any potential triggers (0%, CI 0% to 5.2%). Urine culture was performed in 22 dogs and was positive in three (14%, CI 4.7% to 33.3%). Routine screening tests, particularly thoracic radiographs, have a low yield in identifying potential triggers of associative IMHA, but are more likely to be useful in dogs fulfilling less stringent diagnostic criteria of IMHA.

Update on Albumin Therapy in Critical Illness

Albumin is among the most important proteins and plays a significant role in maintenance of colloid osmotic pressure, wound healing, decreasing oxidative damage, carrying drugs and endogenous substances, and coagulation. Hypoalbuminemia is common in acute and chronic illnesses. Replenishment of albumin can be in the form of fresh frozen, frozen or cryopoor plasma, or in the form of human or canine albumin concentrates. Infusion of human albumin concentrate to healthy and critically ill dogs can induce acute and delayed hypersensitivity reactions. Death has been reported. Therefore, allogenic transfusion in the form of plasma products or canine albumin concentrate is recommended.

Therapeutic Strategies for Treatment of Immune-Mediated Hemolytic Anemia

Immune-mediated hemolytic anemia is a common hematologic disorder in dogs. Disease management involves immunosuppression using glucocorticoids, potentially in combination with other medications such as azathioprine, cyclosporine, or mycophenolate mofetil. Therapeutic drug monitoring may enhance the utility and maximize the safety of cyclosporine and mycophenolate mofetil. The disease is proinflammatory and prothrombotic. Antithrombotic drug administration is therefore essential, and anticoagulant therapy should be initiated at the time of diagnosis. Additional therapies include red blood cell transfusion to support blood oxygen content. Future therapies may include therapeutic plasma exchange, anti-CD20 monoclonal antibodies, and complement inhibitors.

Clinical features of precursor-targeted immune-mediated anemia in dogs: 66 cases (2004-2013)

OBJECTIVE

To characterize the clinical features of dogs with precursor-targeted immune-mediated anemia (PIMA).

ANIMALS

66 dogs with PIMA.

PROCEDURES

Electronic record databases of a teaching hospital were searched to identify dogs with a diagnosis of nonregenerative anemia between 2004 and 2013. Inclusion criteria included persistent nonregenerative anemia (Hct ≤ 30% and reticulocyte count < 76,000 reticulocytes/μL), cytologic findings supportive of ineffective bone marrow erythropoiesis, and absence of underlying disease. Information regarding clinical signs, clinicopathologic findings, treatment, and outcome was extracted from records of eligible dogs. A regenerative response was defined as a reticulocyte count > 76,000 reticulocytes/μL or sustained increase in Hct of > 5%. Remission was defined as a stable Hct ≥ 35%.

RESULTS

The median Hct was 13%, and reticulocyte count was 17,900 reticulocytes/μL. Rubriphagocytosis was identified in bone marrow aspirate samples from 61 of 66 dogs. Collagen myelofibrosis was detected in bone marrow biopsy specimens obtained from 31 of 63 dogs. Immune-mediated targeting of mature erythrocytes was uncommon. All dogs received immunosuppressive therapy. Fifty-five dogs developed a regenerative response at a median of 29 days, and 40 of those dogs went into remission at a median of 59 days after PIMA diagnosis. Thromboembolic events were confirmed for 9 dogs and were associated with a decreased survival time. Median survival time was 913 days for all dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

Results indicated that most dogs with PIMA responded to prolonged immunosuppressive therapy. Studies to determine optimal immunosuppressive and thromboprophylactic protocols for dogs with PIMA are warranted.

The influence of packed cell volume versus plasma proteins on thromboelastographic variables in canine blood

OBJECTIVE

Determine the correlation between kaolin-activated thromboelastography (TEG) variables (R, K, angle, and maximum amplitude [MA]) and PCV, fibrinogen concentration (FC), and total fibrinogen (TF) in an ex vivo model.

ANIMALS

Two healthy adult mixed-breed dogs.

PROCEDURES

Citrated whole blood was obtained and separated into packed red cells, platelet rich plasma, and platelet poor plasma (PPP). An aliquot of PPP was heated to denature heat labile proteins (fibrinogen, factor V, factor VIII). Blood components were recombined for analyses of 6 physiological scenarios: anemia with low fibrinogen; anemia with moderate fibrinogen; anemia with normal fibrinogen; anemia with normal saline; normal PCV and normal fibrinogen; and normal PCV and low fibrinogen. A Kruskal-Wallis test, along with linear regressions on pairwise combinations of TEG variables, was used to determine the correlation between TEG variables and PCV, FC, and TF.

RESULTS

Maximum amplitude correlated with FC (R² 0.60, P < 0.001) and TF (R² 0.57, P < 0.001) but not PCV (R² 0.003, P = 0.7). Angle and K time were moderately correlated with FC ([angle: R² 0.53, P < 0.001]; [K: R² 0.55, P < 0.001]) and TF ([alpha angle: R² 0.52, P < 0.001]; [K: R² 0.51, P < 0.001]) but not PCV. The R time was weakly correlated with PCV (R² 0.15, P < 0.009) but not FC or TF.

CONCLUSIONS AND CLINICAL RELEVANCE

In an ex vivo model, plasma proteins but not PCV impacted TEG variables. This suggests that TEG changes noted with anemia are imparted by changes in available fibrinogen in a fixed microenvironment rather than artifact of anemia.

Evaluation of treatment with a combination of mycophenolate mofetil and prednisolone in dogs with meningoencephalomyelitis of unknown etiology: a retrospective study of 86 cases (2009-2017)

BACKGROUND

Combination therapy with glucocorticoids and adjunctive immunomodulating drugs has been generally accepted as a standard treatment regimen for meningoencephalomyelitis of unknown etiology (MUE). We hypothesized that treatment with MMF as an adjunctive agent along with glucocorticoids would be effective and well-tolerated protocol in dogs with MUE. Eighty-six dogs with MUE between May 2009 and June 2017 were included (59 females and 27 males; mean age of 5.93 years; mean body weight of 3.83 kg). The medical records of dogs with MUE treated with prednisolone and MMF were retrospectively evaluated to determine the therapeutic response, survival time, and treatment-related adverse effects.

RESULTS

A partial or complete response (CR) was recorded for 75 dogs. The overall median survival time from the initiation of treatment was 558 days. Dogs that showed CR with no relapse over the treatment period (from diagnosis to death) had significantly longer median survival times. A significantly higher mortality hazard ratio of 4.546 was recorded in dogs that failed to achieve CR. The interval between the onset of clinical signs and the clinical presentation was not significantly associated with CR, relapse rate, and survival time. Adverse effects included gastrointestinal upsets in 26 dogs (30.23%), sporadic infections in 17 dogs (19.77%), and pancreatitis in seven dogs (8.14%).

CONCLUSIONS

The results suggest that adjunctive MMF treatment for MUE is safe and comparable to other immunosuppressive protocols. The treatment should focus on the achievement of CR and preventing relapse for successful management.

Frequency and classification of errors in laboratory medicine at a veterinary teaching hospital in the United States

BACKGROUND

The accuracy of laboratory data is of utmost importance. Data regarding laboratory error in human laboratories are often extrapolated into veterinary settings. One study investigated the rate and type of errors in a European commercial veterinary laboratory, but that data might not directly apply to an educational setting.

OBJECTIVES

This study determined the frequency and type of errors in laboratory medicine at a veterinary teaching hospital.

METHODS

Errors associated with clinical pathology samples were recorded over two 60-day periods. The first period included a time when new students and house officers started at the veterinary school. The second time period was 6 months later. The errors were assigned to categories, and the frequency of each was calculated. Sample hemolysis, icterus, and lipemia were evaluated separately using an automated index, as these conditions could be pathologic or the result of error. Frequencies of error and hemolysis, icterus, and lipemia were assessed between the groups.

RESULTS

Total error rates were 4.7% and 3.5% for the first and second periods, respectively. The frequency of each error subclassification was similar to those observed in the veterinary and human literature, with preanalytic error predominating. Statistically significant differences in the overall error rate and percentage of preanalytic errors that occurred outside of and within the laboratory were observed comparing differences between the two periods.

CONCLUSIONS

The overall error rate in this veterinary teaching hospital was slightly higher than that previously reported in other settings, although a proportion of errors was as expected. Areas needing improvement were identified, and strategies to reduce error could be developed.

Effects of clopidogrel and prednisone on platelet function in healthy dogs

Background

Glucocorticoids cause hypercoagulability, but it is unknown if they counteract clopidogrel's antiplatelet effects.

Hypothesis/Objectives

Determine the effects of clopidogrel and prednisone on platelet function.

Animals

Twenty‐four healthy dogs.

Methods

Double‐blinded, placebo‐controlled randomized trial. Platelet function was evaluated using a platelet function analyzer and impedance aggregometry (days 0, 14, and 28) for dogs treated with placebo, clopidogrel (2‐3 mg/kg/d), prednisone (2 mg/kg/d), or prednisone with clopidogrel PO for 28 days. Results were categorized as nonresponder versus responder (platelet function analyzer), and inadequate, ideal, or excessive response (aggregometry). Results were compared using mixed model, split‐plot repeated measures analysis of variance and generalized estimating equation proportional odds models. P < .05 was considered significant.

Results

Closure times differed by treatment (F [3, 20] = 10.5; P < .001), time (F [2, 40] = 14.3; P < .001), and treatment‐by‐time (F [6, 40] = 3.4; P = .01). Area under the curve (AUC) differed by treatment (F [3, 20] = 19.6; P < .001), time (F [2, 40] = 35.4; P < .001), and treatment‐by‐time (F [6, 40] = 13.5; P < .001). Based on closure times, 5/6 dogs each in the clopidogrel and prednisone/clopidogrel groups were responders. All dogs in the prednisone/clopidogrel group were overcontrolled based on AUC (days 14 and 28), whereas 5/6 (day 14) and 2/6 (day 28) dogs treated with clopidogrel were overcontrolled. Compared to clopidogrel, dogs receiving prednisone/clopidogrel were 11 times (P = .03) more likely to have an excessive response.

Conclusions and Clinical Importance

Administration of clopidogrel/prednisone increases platelet dysfunction in healthy dogs.

C1 inhibitor in canine intravascular hemolysis (C1INCH): study protocol for a randomized controlled trial

BACKGROUND

Immune-mediated hemolytic anemia (IMHA) is a common disease that affects all breeds of dogs and is associated with significant morbidity and mortality. Intravascular hemolysis of erythrocytes in IMHA is caused by complement activation and is often fatal. No current treatments target complement activation in canine IMHA. Human C₁ esterase (C₁-INH) reduces canine complement-mediated hemolysis in vitro, and a recent pharmacokinetic analysis of an FDA licensed formulation of C₁-INH in dogs confirmed that a 50 IU/kg dose of C₁-INH is safe to administer to dogs, and effectively inhibits canine complement mediated hemolysis ex-vivo. The C₁INCH randomized controlled trial will evaluate the efficacy of this drug in dogs with intravascular hemolysis.

METHODS

We will conduct a multicenter, placebo-controlled double-blind randomized clinical trial of C₁-INH in dogs with intravascular hemolysis due to IMHA. We will randomize 18 dogs to receive three doses of intravenous C₁-INH or saline in 24 h. Immunosuppressive and antithrombotic therapies will be standardized. Primary outcome measures will be changes in plasma free hemoglobin, serum concentrations of LDH, bilirubin, and haptoglobin. Using patient samples, we will evaluate complement activation in canine IMHA using a novel C5b-9 ELISA assay, flow cytometric detection of C3b on RBC, and by measurement of residual plasma complement activity. Secondary outcome measures will be survival to hospital discharge, duration of hospitalization, number and volume of red blood cell transfusions, and rescue therapy requirements. We will monitor dogs for adverse drug reactions. Sample size was estimated from pilot data on LDH and hemolysis index (HI) in dogs with IMHA. To detect 2-way differences between the upper and lower 50% of the LDH and HI values of equivalent size with 80% power at P < 0.05 will require 9 dogs in each arm.

DISCUSSION

We anticipate that IV administration of C1-INH will significantly inhibit complement mediated hemolysis in dogs with intravascular IMHA, as determined by blood biomarker measurements (decreased plasma hemoglobin, LDH and bilirubin, increased haptoglobin). We expect this will translate into significant reductions in transfusion requirements and duration of hospitalization.

TRIAL REGISTRATION

This trial has been prospectively registered with the AVMA registry (AAHSD005025).

Effects of Aspirin and Prednisone on Platelet Function and Thromboxane Synthesis in Healthy Dogs

Glucocorticoid administration is a risk factor for thromboembolism in hypercoagulable dogs, and it is unknown if aspirin counteracts glucocorticoid-induced hypercoagulability. The objective was to determine the effects of sustained aspirin and prednisone administration on platelet function and thromboxane synthesis. Our hypothesis was that aspirin would consistently inhibit platelet function and thromboxane synthesis when administered with or without prednisone. In 24 healthy dogs, platelet aggregometry and urine 11-dehydro-thromboxane-B₂ (11-dTXB₂)-to-creatinine ratios were measured on days 0, 14, and 28. Dogs were administered placebos, aspirin (2 mg/kg/d), prednisone (2 mg/kg/d), or prednisone/aspirin combination therapy PO for 28 days in a randomized double-blinded study. Aspirin response was based on a >25% reduction in platelet aggregation compared to pre-treatment values. Results were compared using mixed model, split-plot repeated measures ANOVAs. P < 0.05 was considered significant. AUC differed significantly by time [F_(2,40) = 10.2, P < 0.001] but not treatment or treatment-by-time. On day 14, 2 dogs were aspirin responders (aspirin, 1; placebo, 1). On day 28, 3 dogs were aspirin responders (aspirin, 2; prednisone/aspirin, 1). Urine 11-dTXB₂-to-creatinine ratios differed significantly by group [F_(3,20) = 3.9, P = 0.024] and time [F_(2,40) = 8.7, P < 0.001), but not treatment-by-time. Post-hoc analysis revealed significant differences between aspirin and placebo groups (P=0.008), aspirin and prednisone/aspirin groups (P = 0.030), and placebo and prednisone groups (P = 0.030). In healthy dogs, sustained aspirin, prednisone, and combination therapy do not inhibit platelet aggregation, and when used as individual therapies, aspirin and prednisone decreased thromboxane synthesis. Additional studies using varied platelet function methodologies in hypercoagulable dogs are necessary.

A Review of the Impact of Neuter Status on Expression of Inherited Conditions in Dogs

Gonadectomy is an important reproductive management tool employed in many countries, and is highly prevalent in the US with an estimated 85% of dogs being neutered. Despite the societal benefits in pet population control, negative associations between neuter status, and health conditions have been reported in recent years. Most particularly observed are the consequences of early age neutering. Knowing that different physiological systems rely upon gonadal steroids during development and physiological maintenance, studies have been undertaken to assess the impact of neuter status on multiple body and organ systems. For some inherited conditions, neutering is associated with an increased risk of expression. Neutering has also been associated with altered metabolism and a predisposition for weight gain in dogs, which may confound the detected risk association between neutering and disease expression. This review summarizes the effects of neutering on cancer, orthopedic, and immune disorders in the dog and also explores the potentially exacerbating factor of body weight.

Clinical, clinicopathologic, and gastrointestinal changes from administration of clopidogrel, prednisone, or combination in healthy dogs: A double-blind randomized trial

Background

Dogs with immune‐mediated disease often receive glucocorticoids with clopidogrel, but ulcerogenic effects of current protocols are unknown.

Hypothesis/Objectives

To compare gastrointestinal endoscopic findings among dogs administered clopidogrel, prednisone, and combination treatment.

Animals

Twenty‐four healthy research dogs.

Methods

Double‐blinded, placebo‐controlled randomized trial. Dogs received placebo, clopidogrel (2–3 mg/kg q24h), prednisone (2 mg/kg q24h), or prednisone with clopidogrel PO for 28 days. Attitude, food intake, vomiting, and fecal score were determined daily. Clinicopathologic testing was performed at baseline and on day 28. Gastrointestinal hemorrhages, erosions, and ulcers were numerated by 2 blinded investigators for endoscopies performed on days 0, 14, and 28, and endoscopic mucosal lesion scores were calculated. Results were compared using mixed model, split‐plot repeated measures ANOVAs and generalized estimating equation proportional odds models as appropriate. P < .05 was considered significant.

Results

Clinical signs of gastrointestinal bleeding were not noted. Endoscopic mucosal lesion scores differed significantly by group (F[3, 20] = 12.8, P < .001) and time (F[2, 40] = 8.3, P < .001). Posthoc analysis revealed higher lesion scores in the prednisone‐receiving groups (P ≤ .006 for each) and on day 14 (P ≤ .007 for each). Ulcers were identified in 4 dogs administered prednisone and 3 dogs administered prednisone/clopidogrel. Odds of having endoscopic mucosal lesion scores ≥4 were 7‐times higher for dogs in prednisone (95%CI 1.1, 43.0; P = .037) and prednisone‐clopidogrel (95%CI 1.1, 43.4; P = .037) groups than those in the placebo group.

Conclusions and Clinical Importance

Gastrointestinal bleeding and ulceration occur commonly in healthy dogs administered prednisone or prednisone/clopidogrel treatment, but not clopidogrel monotherapy. Though lesions are severe in many cases, they are not accompanied by clinical signs.

The utility of diagnostic tests for immune-mediated hemolytic anemia

BACKGROUND

A definitive diagnosis of immune-mediated hemolytic anemia (IMHA) can be difficult to make. However, it is critical to differentiate IMHA from other causes of anemia due to the impact on prognosis and outcome for IMHA patients. Recently published American College of Veterinary Internal Medicine recommendations for the diagnosis of IMHA should be followed to concurrently confirm ongoing anemia, verify in vivo hemolysis, and detect anti-erythrocyte antibodies. The reliability of immunologic IMHA tests varies depending on which test is used and how it is performed.

OBJECTIVES

Our aims were to determine which tests are currently used in veterinary medicine to diagnose IMHA and review the utility of assays that have historically been used to diagnose IMHA.

METHODS

A short survey was designed to see which diagnostic tests for IMHA were currently being used by veterinary practices. The survey was distributed via list-serves to veterinarians and veterinary technologists. A literature review was performed to report the utility of diagnostic tests for the diagnosis of IMHA.

RESULTS

Survey respondents indicated a variability in test protocols used to diagnose IMHA. Most respondents perform saline agglutination or Coombs' tests to detect anti-erythrocyte antibodies. Additional tests that can be used to support a diagnosis of IMHA are discussed in this review.

CONCLUSIONS

A standardized diagnostic approach should be followed to differentiate IMHA from other causes of anemia. Test methodology can vary from one laboratory to another, and clinicians should be familiar with the procedures used by their laboratory.

Primary immune-mediated haemolytic anaemia: a retrospective long-term study in 61 dogs

OBJECTIVES

The objective of this study is to describe the course of disease of dogs with primary immune-mediated haemolytic anaemia (pIMHA) with an observation period longer than 90 days in regard to clinical signs, laboratory results and treatment response.

MATERIAL AND METHODS

Clinical records between January 2003 and December 2011 were reviewed. Diagnosis of pIMHA was based on the presence of haemolytic anaemia with a packed cell volume of <0.35 L/L, a positive Coombs' test and/or erythrocyte agglutination, spherocytosis and exclusion of an underlying disease. Included were dogs which could be monitored for more than 90 days after initial presentation.

RESULTS

Sixty-one dogs with pIMHA were included. The initial packed cell volume ranged from 0.08 to 0.30 L/L (median 0.16). Immunosuppressive treatment included prednisolone in all the cases; 32 dogs successively received cyclosporine (28), cyclophosphamide (5), leflunomide (2) or human intravenous immunoglobulins (2) in addition. In 33/61 dogs, the drugs were discontinued 67-3372 days (median 334) after beginning of therapy; in 28 dogs, the drug dosage was reduced, but not discontinued until the end of the study. Three dogs developed immune-mediated thrombocytopenia (days 132, 156 and 680). The observation period ranged from 96 to 4147 days (median 628). A total of 22.9% (14/61) of the dogs developed a relapse after 94-3972 days (median 517). Five dogs were euthanased due to a relapse after 96-1188 days (median 628).

CLINICAL SIGNIFICANCE

Long-term prognosis in dogs with pIMHA is favourable. However, a relapse can occur after many years. Relapse was the most common cause of death in dogs with pIMHA that survive more than 90 days.

Clinical, clinicopathologic, and gastrointestinal changes from aspirin, prednisone, or combination treatment in healthy research dogs: A double-blind randomized trial

Background

Dogs with immune‐mediated disease are often coadministered glucocorticoids and aspirin, but ulcerogenic effects of current protocols are unknown.

Objectives

To compare gastrointestinal changes among dogs administered aspirin, prednisone, and combination treatment.

Animals

Twenty‐four healthy research dogs.

Methods

Double‐blinded, placebo‐controlled randomized trial of dogs administered placebo, aspirin (2 mg/kg q24h), prednisone (2 mg/kg q24h), or combination treatment PO for 28 days. Clinical signs were recorded daily, with laboratory work performed at baseline and day 28. Gastrointestinal mucosal hemorrhages, erosions, and ulcers were numerated for endoscopic studies performed on days 0, 14, and 28; endoscopic mucosal lesion scores were calculated. Results were compared using mixed model repeated‐measures analyses of variance and generalized estimating equation proportional odds models. P < .05 was considered significant.

Results

Gastric mucosal lesion scores differed by treatment‐by‐time (F[6, 40] = 4.4, P = .002), treatment (F[3, 20] = 7.1, P = .002), and time (F[2, 40] = 18.9, P < .001). Post hoc analysis revealed increased scores in the aspirin (day 14 only), prednisone, and prednisone/aspirin groups during treatment. Ulcers were identified on 14 studies, representing 10 dogs. Dogs receiving prednisone and prednisone/aspirin had 11.1 times (95% CI, 1.7‐73.6) and 31.5 times (95% CI, 3.5‐288.0) higher odds, respectively, of having endoscopic mucosal lesion scores ≥4 than dogs receiving placebo (P ≤ .01).

Conclusions and Clinical Importance

Gastrointestinal bleeding occurs commonly in dogs administered aspirin, prednisone, or prednisone/aspirin treatment, with higher lesion scores for dogs receiving combination treatment. Even severe lesions are not accompanied by clinical signs.

Optimal Vector-borne Disease Screening in Dogs Using Both Serology-based and Polymerase Chain Reaction-based Diagnostic Panels

Vector-borne disease and idiopathic immune-mediated disease present similarly. Diagnostic panels that include multiple organisms help detect infection and identify coinfections. Comprehensive diagnostic panels that combine polymerase chain reaction (PCR) and serology should be used in initial screening to maximize sensitivity and identify infection. Repeat testing using PCR is warranted in dogs at high risk of infection with organisms that circulate in blood in low numbers or intermittently. Convalescent serologic testing can help diagnose acute infection. This article discusses the pathophysiology and epidemiology of the organisms, panel selection, and how to recognize when more aggressive testing for an organism is warranted.

ACVIM consensus statement on the treatment of immune-mediated hemolytic anemia in dogs

Immune‐mediated hemolytic anemia (IMHA) causes severe anemia in dogs and is associated with considerable morbidity and mortality. Treatment with various immunosuppressive and antithrombotic drugs has been described anecdotally and in previous studies, but little consensus exists among veterinarians as to the optimal regimen to employ and maintain after diagnosis of the disease. To address this inconsistency and provide evidence‐based guidelines for treatment of IMHA in dogs, we identified and extracted data from studies published in the veterinary literature. We developed a novel tool for evaluation of evidence quality, using it to assess study design, diagnostic criteria, explanation of treatment regimens, and validity of statistical methods. In combination with our clinical experience and comparable guidelines for humans afflicted with autoimmune hemolytic anemia, we used the conclusions of this process to make a set of clinical recommendations regarding treatment of IMHA in dogs, which we refined subsequently by conducting several iterations of Delphi review. Additionally, we considered emerging treatments for IMHA in dogs and highlighted areas deserving of future research. Comments were solicited from several professional bodies to maximize clinical applicability before the recommendations were submitted for publication. The resulting document is intended to provide clinical guidelines for management of IMHA in dogs. These guidelines should be implemented pragmatically, with consideration of animal, owner, and veterinary factors that may vary among cases.

American College of Veterinary Emergency and Critical Care (ACVECC) Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines: Small animal

OBJECTIVES

To systematically review available evidence and establish guidelines related to the risk of developing thrombosis and the management of small animals with antithrombotics.

DESIGN

Standardized, systematic evaluation of the literature (identified by searching Medline via PubMed and CAB abstracts) was carried out in 5 domains (Defining populations at risk; Defining rational therapeutic use; Defining evidence-based protocols; Refining and monitoring antithrombotic therapies; and Discontinuing antithrombotic therapies). Evidence evaluation was carried out using Population, Intervention, Comparison, Outcome generated within each domain questions to address specific aims. This was followed by categorization of relevant articles according to level of evidence and quality (Good, Fair, or Poor). Synthesis of these data led to the development of a series of statements. Consensus on the final guidelines was achieved via Delphi-style surveys. Draft recommendations were presented at 2 international veterinary conferences and made available for community assessment, review, and comment prior to final revisions and publication.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Over 500 studies were reviewed in detail. Worksheets from all 5 domains generated 59 statements with 83 guideline recommendations that were refined during 3 rounds of Delphi surveys. A high degree of consensus was reached across all guideline recommendations.

CONCLUSIONS

Overall, systematic evidence evaluations yielded more than 80 recommendations for the treatment of small animals with or at risk of developing thrombosis. Numerous significant knowledge gaps were highlighted by the evidence reviews undertaken, indicating the need for substantial additional research in this field.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 1-Defining populations at risk

OBJECTIVES

Thrombosis is a well-recognized phenomenon in dogs and cats with a significant impact on morbidity and mortality. Despite growing awareness of thrombosis and increased use of antithrombotic therapy, there is little information in the veterinary literature to guide the use of anticoagulant and antiplatelet medications. The goal of Domain 1 was to explore the association between disease and thrombosis in a number of conditions identified as potential risk factors in the current veterinary literature, to provide the basis for prescribing recommendations.

DESIGN

A population exposure comparison outcome format was used to represent patient, exposure, comparison, and outcome. Population Exposure Comparison Outcome questions were distributed to worksheet authors who performed comprehensive searches, summarized the evidence, and created guideline recommendations that were reviewed by domain chairs. Revised guidelines then underwent the Delphi survey process to reach consensus on the final guidelines. Diseases evaluated included immune-mediated hemolytic anemia, protein-losing nephropathy, pancreatitis, glucocorticoid therapy, hyperadrenocorticism, neoplasia, sepsis, cerebrovascular disease, and cardiac disease.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Of the diseases evaluated, a high risk for thrombosis was defined as dogs with immune-mediated hemolytic anemia or protein-losing nephropathy, cats with cardiomyopathy and associated risk factors, or dogs/cats with >1 disease or risk factor for thrombosis. Low or moderate risk for thrombosis was defined as dogs or cats with a single risk factor or disease, or dogs or cats with known risk factor conditions that are likely to resolve in days to weeks following treatment.

CONCLUSIONS

Documented disease associations with thrombosis provide the basis for recommendations on prescribing provided in subsequent domains. Numerous knowledge gaps were identified that represent opportunities for future study.

Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE): Domain 3-Defining antithrombotic protocols

OBJECTIVES

To systematically examine the evidence for use of a specific protocol (dose, frequency, route) of selected antithrombotic drugs, in comparisons to no therapy or to other antithrombotic therapies, to reduce the risk of complications or improve outcomes in dogs and cats at risk for thrombosis.

DESIGN

Standardized, systematic evaluation of the literature, categorization of relevant articles according to level of evidence (LOE) and quality (Good, Fair, or Poor), and development of consensus on conclusions via a Delphi-style survey for application of the concepts to clinical practice.

SETTINGS

Academic and referral veterinary medical centers.

RESULTS

Databases searched included Medline via PubMed and CAB abstracts. Eight different antithrombotic drugs were investigated using a standardized Patient, Intervention, Comparison, Outcome (PICO) question format both for dogs and cats, including aspirin, clopidogrel, warfarin, unfractionated heparin (UFH), dalteparin, enoxaparin, fondaparinux, and rivaroxaban, generating a total of 16 worksheets. Most studies identified were experimental controlled laboratory studies in companion animals (LOE 3) with only four randomized controlled clinical trials in companion animals (LOE 1).

CONCLUSIONS

Overall, evidence-based recommendations concerning specific protocols could not be formulated for most antithrombotic drugs evaluated, either because of the wide range of dosage reported (eg, aspirin in dogs) or the lack of evidence in the current literature. However, clopidogrel administration in dogs and cats at risk of arterial thrombosis, notably in cats at risk of cardiogenic thromboembolism, is supported by the literature, and specific protocols were recommended. Comparably, aspirin should not be used as a sole antithrombotic in cats with cardiomyopathy. Using the available safety profile information contained in the literature, the panel reached consensus on suggested dosage schemes for most antithrombotics. Significant knowledge gaps were highlighted, which will hopefully drive novel research.