Retrospective study of 871 dogs with thrombocytopenia

Prostate tissue ablation and drug delivery by an image-guided injectable ionic liquid in ex vivo and in vivo models

Benign prostatic hyperplasia and prostate cancer are often associated with lower urinary tract symptoms, which can severely affect patient quality of life. To address this challenge, we developed and optimized an injectable compound, prostate ablation and drug delivery agent (PADA), for percutaneous prostate tissue ablation and concurrently delivered therapeutic agents. PADA is an ionic liquid composed of choline and geranic acid mixed with anticancer therapeutics and a contrast agent. The PADA formulation was optimized for mechanical properties compatible with hand injection, diffusion capability, cytotoxicity against prostate cells, and visibility of an x-ray contrast agent. PADA also exhibited antibacterial properties against highly resistant clinically isolated bacteria in vitro. Ultrasound-guided injection, dispersion of PADA in the tissue, and tissue ablation were tested ex vivo in healthy porcine, canine, and human prostates and in freshly resected human tumors. In vivo testing was conducted in a murine subcutaneous tumor model and in the canine prostate. In all models, PADA decreased the number of viable cells in the region of dispersion and supported the delivery of nivolumab throughout a portion of the tissue. In canine survival experiments, there were no adverse events and no impact on urination. The injection approach was easy to perform under ultrasound guidance and produced a localized effect with a favorable safety profile. These findings suggest that PADA is a promising therapeutic prostate ablation strategy to treat lower urinary tract symptoms.

ACVIM consensus statement on the diagnosis of immune thrombocytopenia in dogs and cats

Immune thrombocytopenia (ITP) is the most common acquired primary hemostatic disorder in dogs. Immune thrombocytopenia less commonly affects cats but is an important cause of mortality and treatment-associated morbidity in both species. Immune thrombocytopenia remains a diagnosis of exclusion for which diagnostic guidelines are lacking. Primary, or non-associative, ITP refers to autoimmune platelet destruction. Secondary, or associative, ITP arises in response to an underlying disease trigger. However, evidence for which comorbidities serve as ITP triggers has not been systematically evaluated. To identify key diagnostic steps for ITP and important comorbidities associated with secondary ITP, we developed 12 Population Evaluation/Exposure Comparison Outcome (PECO) format questions. These questions were addressed by evidence evaluators utilizing a literature pool of 287 articles identified by the panelists using a structured search strategy. Evidence evaluators, using panel-designed templates and data extraction tools, summarized evidence and created guideline recommendations that then were integrated by diagnosis and comorbidity domain chairs. The revised PECO responses underwent a Delphi survey process to reach consensus on final guidelines. A combination of panel expertise and PECO responses were employed to develop algorithms for diagnosis of ITP in dogs and cats, which also underwent 4 iterations of Delphi review. Comorbidity evidence evaluators employed an integrated measure of evidence (IME) tool to determine evidence quality for each comorbidity; IME values combined with evidence summaries for each comorbidity were integrated to develop ITP screening recommendations, which also were subjected to Delphi review. Commentary was solicited from multiple relevant professional organizations before finalizing the consensus. The final consensus statement provides clinical guidelines for the diagnosis of, and underlying disease screening for, ITP in dogs and cats. The systematic consensus process identified numerous knowledge gaps that should guide future studies. This statement is a companion manuscript to the ACVIM Consensus Statement on the Treatment of Immune Thrombocytopenia.

Evaluation of activation characteristics of a canine platelet concentrate produced by a commercial double centrifugation system

Introduction

In veterinary medicine there are few readily available products for platelet transfusion to patients with thrombocytopenia. Commercial tabletop platelet concentrating systems have recently become available to veterinarians, primarily directed towards uses associated with regenerative medicine. These systems could potentially be used to produce fresh concentrated platelets for use in transfusion medicine. This study evaluated the concentration, activation, and sterility of a double centrifugation platelet concentrate (PC) produced by a commercial benchtop system.

Methods

Ten healthy dogs were studied. Whole blood was collected and mixed with ACD-A in a 1:7.6 ratio of ACD-A to whole blood. 12 mL of this mixture was processed into PC via single centrifugation, while 60 mL of the anticoagulated whole blood was processed via a commercial double centrifugation system. Both types of PC were evaluated for platelet concentration, CD62P expression with and without thrombin stimulation, and for sterility.

Results

Mean platelet count in the double centrifuged PC was 863 ± 352 × 103/μL, with very low white blood cell contamination (median of 0.47 × 103 leukocyte/μL (range 0.15-2.18 × 103/μL)). The double-centrifuged PC had similar baseline activation characteristics (as determined by P-selectin expression) as the single centrifuge PC (0.76% vs. 0.72% unstimulated, 30.5% vs. 34.9% stimulated, p = 0.432).

Discussion

The benchtop PC system studied here did not cause activation of platelets during production and produced a sterile product that can be further investigated as a source of fresh platelet concentrates for transfusion purposes.

A novel ITGA2B double cytosine frameshift variant (c.1986_1987insCC) leads to Glanzmann's thrombasthenia in a cat

BACKGROUND

Glanzmann's thrombasthenia (GT) is a congenital platelet disorder affecting approximately 1:1 000 000 people globally and characterized by impaired platelet aggregation and clot retraction. Autosomal recessive, loss-of-function, variants in ITGA2B or ITGB3 of the αIIbβ3 receptor cause the disease in humans. A cat affected by Glanzmann's and macrothrombocytopenia was presented to the UC Davis VMTH.

HYPOTHESIS/OBJECTIVES

Severe thrombopathia in this cat has an underlying genetic etiology.

ANIMALS

A single affected patient, 2 age-matched clinically healthy controls, and a geriatric population (n = 20) of normal cats.

METHODS

Physical examination and clinical pathology tests were performed on the patient. Flow cytometry and platelet aggregometry analyses for patient phenotyping were performed. Patient and validation cohort gDNA samples were extracted for Sanger sequencing of a previously identified ITGA2B (c.1986delC) variant. Reverse transcriptase PCR was performed on patient and healthy control PRP samples to verify ITGA2B variant consequence.

RESULTS

A novel c.1986_1987insCC autosomal recessive variant in ITGA2B was identified. This variant was absent in a population of 194 unrelated cats spanning 44 different breeds. Complete loss of ITGA2B transcript and protein expression was verified by RT-PCR and flow cytometry, explaining the underlying etiology of GT, and likely macrothrombocytopenia, in this cat.

CONCLUSIONS AND CLINICAL IMPORTANCE

This study emphasizes the role of precision medicine in cardiovascular disease of cats and identified yet another variant that may be of utility for screening in the feline population. This study provides a small-volume, standardized, successful protocol for adequate platelet RNA isolation and subsequent molecular assessment of gene expression in cats.

Retrospective evaluation of leflunomide as an adjunctive therapy in dogs with non-associative immune-mediated thrombocytopenia: 20 cases (2008-2021)

OBJECTIVE

To describe leflunomide as an adjunctive therapy in the treatment of non-associative immune-mediated thrombocytopenia.

MATERIALS AND METHODS

A retrospective study of dogs with a diagnosis of non-associative immune-mediated thrombocytopenia treated with leflunomide March 2008 to September 2021 was conducted. Data collected included signalment, clinical signs, physical examination findings and diagnostic testing performed. Medications administered, duration of hospital stay, time to platelet concentration >150×109/L and adverse events during leflunomide therapy were recorded. Relapses within a year of diagnosis were reported.

RESULTS

A total of 20 client-owned dogs met inclusion criteria. Nineteen of 20 dogs (95%) achieved a platelet concentration >150×109/L with leflunomide and prednisone combination therapy and four dogs (21.1%) relapsed during treatment or shortly after treatment. Adverse effects included diarrhoea (n=5), mild lymphopenia (n=9) and mild intermittent anaemia (n=1). A single dog developed hepatotoxicity presumed to be secondary to leflunomide therapy that resolved after drug discontinuation. One dog was treated for aspiration pneumonia during treatment. Two dogs were euthanased while receiving leflunomide.

CLINICAL SIGNIFICANCE

Length of hospitalisation, time to platelet recovery, treatment response and relapse rate were comparable with alternative treatment protocols. Most adverse effects did not require leflunomide dose adjustment; however, two dogs died while undergoing leflunomide treatment and there is compelling evidence that one of these dogs experienced fatal infection secondary to immune-suppression. Hepatotoxicity remains a known complication of leflunomide treatment and serial biochemistry testing is recommended.

A prospective cohort study to identify clinical diagnostic and prognostic markers of primary immune thrombocytopenia in dogs

BACKGROUND

Primary immune thrombocytopenia (pITP) in dogs presents a diagnostic challenge, and clinical markers of severity are lacking.

OBJECTIVES

Identify clinicopathologic features that differentiate pITP from secondary ITP (sITP) and markers related to bleeding severity, transfusion, and survival of dogs with pITP.

ANIMALS

Ninety-eight thrombocytopenic dogs (58 pITP and 40 sITP).

METHODS

Client-owned dogs with platelet counts <50 000/μL were enrolled in a prospective, multi-institution cohort study. History and treatment information, through a maximum of 7 days, was recorded on standard data forms. Bleeding severity was scored daily using a bleeding assessment tool (DOGiBAT). At-admission blood samples were collected for CBC, biochemistry, C-reactive protein concentration, and coagulation panels, and to measure platelet surface-associated immunoglobulin G (PSAIg) and expression of platelet membrane proteins and phospholipids. Dogs with evidence of coincident disease were classified as sITP.

RESULTS

No definitive pITP diagnostic test was found. However, pITP cases were characterized by lower platelet counts, D dimer concentrations, and platelet membrane protein expression than sITP cases. Differentiation between pITP and sITP was further enhanced using logistic regression modeling combining patient sex, coagulation profile, platelet count, D dimer, and PSAIg. A second model of pITP severity indicated that low hematocrit and high BUN concentration were associated with non-survival. Low hematocrit at admission, but not platelet count or DOGiBAT score, was associated with transfusion.

CONCLUSIONS AND CLINICAL IMPORTANCE

Pending validation studies, models constructed from at-admission clinicopathologic findings may improve differentiation of pITP from sITP and identify the most severe pITP cases at the time of presentation.

Effects of canine influenza infection and DA2PP vaccination on the development of platelet-associated immunoglobulins and platelet counts in dogs

BACKGROUND

Immune thrombocytopenia (ITP) is commonly associated with platelet-associated immunoglobulins (PAIg). Demonstration of PAIg can help determine etiologies for thrombocytopenia. In humans, ITP and thrombocytopenia have been associated with various vaccinations and influenza infections, respectively.

OBJECTIVES

We aimed to evaluate platelet counts and PAIg in research dogs with H3N2 and in research and client-owned dogs routinely vaccinated for distemper, adenovirus-2, parainfluenza, and parvovirus (DA2PP). The hypotheses were that H3N2 infection but not DA2PP vaccination would decrease platelet counts, and neither would result in the detection of PAIg.

METHODS

Three pilot studies. Platelet counts and PAIg, measured by direct flow cytometry as %IgG, were evaluated in eight research Beagles following experimental infection with H3N2 (experiment 1), nine research Beagles vaccinated for DA2PP (experiment 2), and thirty client-owned dogs vaccinated for DA2PP (experiment 3). All animals were considered healthy at the start of the experiments.

RESULTS

Transient, self-resolving decreases in platelet counts and increases in %IgG occurred following H3N2 infection, and one dog became thrombocytopenic and positive for PAIg. Following DA2PP vaccination, %IgG increased in research and client-owned dogs, but only one dog was considered positive for PAIg with a concurrent increase in platelet count. Mean PAIg increased from baseline in client-owned dogs following vaccination.

CONCLUSIONS

Transient PAIg and thrombocytopenia can occur following H3N2 infection, while routine vaccination for DA2PP in this group of dogs was not associated with the development of thrombocytopenia or clinically relevant formation of PAIg.

Plasma urea:creatinine ratio as a biomarker of gastrointestinal bleeding in dogs with anaemia

BACKGROUND

Gastrointestinal bleeding is a cause of anaemia in dogs. A reliable, non-invasive biomarker to differentiate gastrointestinal bleeding from other causes of anaemia would be advantageous to direct clinical decisions in anaemic patients. Plasma urea:creatinine ratio is an accepted biomarker of upper gastrointestinal bleeding in human medicine.

OBJECTIVES

The objective of this study was to evaluate plasma urea:creatinine ratio as a biomarker of gastrointestinal bleeding in a population of dogs with anaemia.

METHODS

This was a prospective cross-sectional study of dogs with anaemia presenting to referral centres for the investigation of anaemia. Cases were categorised as having overt gastrointestinal bleeding (melena on presentation), occult gastrointestinal bleeding (historical and diagnostic findings consistent with gastrointestinal bleeding without melena at presentation) or anaemia of other cause (confident diagnosis other than gastrointestinal bleeding reached, normal diagnostic imaging of gastrointestinal tract). Urea:creatinine ratio at presentation was calculated by dividing urea (mg/dL) by creatinine (mg/dL).

RESULTS

Ninety-five dogs were included. Plasma urea:creatinine ratio was not significantly different between dogs with overt or occult gastrointestinal bleeding or those with anaemia of other cause (median urea:creatinine ratio 25.8, 20.7 and 22.5, respectively). No significant difference in urea:creatinine ratio was found between dogs with upper and lower gastrointestinal bleeding (median urea:creatinine ratio 19.4 and 24.6, respectively).

CONCLUSIONS

Plasma urea:creatinine ratio was not helpful in differentiating between dogs with anaemia resulting from gastrointestinal bleeding (overt or occult) and those with other causes of anaemia.

Clinical Assessment of Primary Hemostasis: A Review

Primary hemostatic disorders such as thrombocytopenia and thrombocytopathia are commonly encountered in small animal practice. The key stages of primary hemostasis include platelet adhesion, activation, and aggregation. Understanding the interaction between tissues, platelets, and signaling molecules not only helps clinicians comprehend clot formation but also better recognize thrombocytopathias. Although congenital thrombocytopathia is rare, commercially available platelet function tests allow veterinarians to narrow differentials in many clinical settings. Thrombocytopenia can be easily diagnosed in any clinical setting. In this paper, we review the current understanding of primary hemostasis in veterinary medicine, including the clinical presentation and available diagnostics to identify platelet abnormalities.

Use of tranexamic acid in dogs with primary immune thrombocytopenia: A feasibility study

Objective

The aim of this feasibility study is to evaluate the use of tranexamic acid and its safe use alongside standard therapy in dogs with primary immune thrombocytopenia (ITP).

Design

This is a cohort feasibility study involving 10 dogs diagnosed with primary ITP that received standard therapy for ITP including corticosteroids, a single dose of vincristine, and omeprazole. Dogs were randomly divided into either the control group (n = 6) or the group receiving tranexamic acid (TXA group, n = 4).

Key findings

The mean time from the start of treatment until remission was 5 days in the TXA group and 6 days in the control group (P = 0.69). Two dogs, one in each group, did not achieve remission. Clinical bleeding scores were not significantly different between both groups (p = 0.43), and the median blood volume administered was 37.5 ml/kg for the TXA group and 9.72 ml/kg for the control group (p = 0.084). Three out of the four dogs receiving TXA of 20 mg/kg IV started vomiting within 15 min of administration and were given a reduced dose of 15 or 10 mg/kg IV.

Conclusion

Tranexamic acid did not confer a clinical benefit in this small cohort study and was associated with a high incidence of vomiting. This study provides useful information for the design of future trials in dogs with ITP receiving tranexamic acid including outcome measures and safety.

Preliminary evaluation of a flow cytometric assay with microsphere controls for the detection of platelet-bound antibodies in canine immune thrombocytopenia

BACKGROUND

Canine immune thrombocytopenia (ITP) ranges from a mild to severe bleeding disorder, and platelet counts do not reliably predict clinical disease course. The detection of platelet autoantibodies may further define the disease phenotype, but variability in assay configurations and a lack of well-characterized controls limit the diagnostic utility of anti-platelet antibody assays.

OBJECTIVES

We aimed to develop control reagents to facilitate the characterization of canine platelet surface-associated immunoglobulin (PSAIg) in flow cytometric assays.

METHODS

Silica microspheres were coated with canine IgG and IgM to assess the reactivity of goat and rabbit origin anti-canine immunoglobulin reagents. They were also used as positive controls in the PSAIg assay. Preliminary assay evaluation and determination of sample stability used PRP isolated from seven healthy dogs and 26 dogs newly diagnosed with thrombocytopenia.

RESULTS

Blood sample stability was established for up to a 48-hour storage time. The conjugated positive control microspheres demonstrated stable fluorescent labeling over a 2-year observation period. Rabbit and goat origin anti-dog IgM fluorescent antibody labels reacted nonspecifically with canine IgG. Rabbit origin anti-dog IgG antibody demonstrated greater class specificity for canine IgG than a goat origin antibody. Thrombocytopenic dogs had a broad range of membrane-bound immunoglobulin. Median PSAIgG for dogs with primary or secondary ITP (18.4%, 34.1%, respectively) were significantly higher than controls (3.8%, P < .05).

CONCLUSIONS

The described assay reagents and procedures provide positive controls and allow consistent thresholding to define a positive test result, suitable for any flow cytometer. A rabbit anti-dog IgG fluorescent label demonstrated specificity for canine IgG and was useful for the detection of PSAIgG in thrombocytopenic dogs.

Immunomodulatory and immunosuppressive drug protocols in the treatment of canine primary immune thrombocytopenia, a scoping review

Primary immune thrombocytopenia (ITP) is a cause of severe thrombocytopenia in dogs. Immunosuppressive corticosteroid drugs are frequently used in the management of ITP, but treatment failure may occur. Immunomodulatory and non-corticosteroid immunosuppressive drugs might improve outcomes from therapy either alone or in combination with corticosteroids. The objectives of this scoping review were (1) to evaluate the current evidence relating to immunomodulatory and immunosuppressive drug protocols in the treatment of canine ITP, and (2) to answer the clinical question, whether or not therapy with immunomodulatory or non-corticosteroid immunosuppressive drugs alone or in combination with corticosteroids could improve outcome, compared to therapy with corticosteroids alone. A literature search was performed in the electronic databases of Agricola, CAB Abstracts, Embase, Medline and Web of Science for publications in November 2019 and again February 1, 2021. Selection criteria were relatively strict and included peer-reviewed research papers reporting outcome measures from immunomodulatory and immunosuppressive drug protocols in the treatment of canine ITP with a pre-therapeutic mean or median platelet count < 50,000/µL as a strict criterion for inclusion. Studies were evaluated if they had an appropriate diagnostic work up to exclude underlying conditions. Outcome measures and adverse events were compared between drug protocols both within studies and between studies. The search identified 456 studies, with six studies being eligible for inclusion. The studies were mostly case series while two were randomized controlled trials. Level of evidence varied with an overall uncertain subject enrollment, small groups, inadequate description and variable use of drug protocols or outcome measures. For outcomes such as platelet recovery time and duration of hospitalization, an improvement was observed using adjunctive therapy (human intravenous immunoglobulin) compared to therapy with corticosteroids alone. For outcomes of complete platelet recovery time, survival (6-month), mortality and relapse, no improvement was observed using adjunctive drugs compared to corticosteroids alone. Specifically, therapy with mycophenolate mofetil alone and adjunctive azathioprine were associated with more severe adverse events compared to other drug protocols. Evidence relating to immunomodulatory and immunosuppressive drug protocols in the treatment of canine ITP was of variable quality. Future larger case-controlled trials are required for determination of optimal treatment protocols in canine ITP.

Lyophilized platelets versus cryopreserved platelets for management of bleeding in thrombocytopenic dogs: A multicenter randomized clinical trial

Background

Thrombocytopenia in dogs is common in critical care medicine, but availability of fresh platelet concentrates in veterinary medicine can be limiting. Lyophilized platelets have long shelf‐lives and can be easily transported, stored, and administered in various settings.

Objective

To evaluate the efficacy and safety of a novel trehalose‐stabilized canine lyophilized platelet product in thrombocytopenic dogs with clinically‐evident bleeding.

Animals

Eighty‐eight dogs with platelet counts <50 × 10³/μL and a standardized bleeding assessment tool (DOGiBAT) score ≥2.

Methods

Multicenter, randomized, non‐blinded, non‐inferiority clinical trial comparing dimethyl sulfoxide (DMSO)‐stabilized cryopreserved platelet concentrates (CPP) with trehalose‐stabilized lyophilized platelets (LP) for control of bleeding in thrombocytopenic dogs. Dogs were randomized to receive 3 × 10⁹ platelets/kg of LP or CPP. Primary outcome measures were change in DOGiBAT score, platelet count, need for additional red cell transfusion and all‐cause mortality.

Results

Fifty dogs received LP and 38 received CPP. Baseline demographics and clinical characteristics of both groups were comparable. At 1‐hour post‐transfusion, LP were superior for change in DOGiBAT score, and non‐inferior at 24‐hours post‐transfusion. The LP were non‐inferior to CPP for change in platelet count, need for additional red blood cell units, and survival to discharge. The LP were superior for change in hematocrit at 1‐hour post‐transfusion, and non‐inferior at 24‐hours. No adverse effects were noted in either group.

Conclusions and Clinical Importance

A novel trehalose‐stabilized canine LP product appears to be logistically superior and is clinically non‐inferior to DMSO‐stabilized canine CPP for management of bleeding in thrombocytopenic dogs.

A review of hyperfibrinolysis in cats and dogs

The fibrinolytic system is activated concurrently with coagulation; it regulates haemostasis and prevents thrombosis by restricting clot formation to the area of vascular injury and dismantling the clot as healing occurs. Dysregulation of the fibrinolytic system, which results in hyperfibrinolysis, may manifest as clinically important haemorrhage. Hyperfibrinolysis occurs in cats and dogs secondary to a variety of congenital and acquired disorders. Acquired disorders associated with hyperfibrinolysis, such as trauma, cavitary effusions, liver disease and Angiostrongylus vasorum infection, are commonly encountered in primary care practice. In addition, delayed haemorrhage reported in greyhounds following trauma and routine surgical procedures has been attributed to a hyperfibrinolytic disorder, although this has yet to be characterised. The diagnosis of hyperfibrinolysis is challenging and, until recently, has relied on techniques that are not readily available outside referral hospitals. With the recent development of point-of-care viscoelastic techniques, assessment of fibrinolysis is now possible in referral practice. This will provide the opportunity to target haemorrhage due to hyperfibrinolysis with antifibrinolytic drugs and thereby reduce associated morbidity and mortality. The fibrinolytic system and the conditions associated with increased fibrinolytic activity in cats and dogs are the focus of this review article. In addition, laboratory and point-of-care techniques for assessing hyperfibrinolysis and antifibrinolytic treatment for patients with haemorrhage are reviewed.

Immune thrombocytopenia (ITP): Pathophysiology update and diagnostic dilemmas

Immune thrombocytopenia (ITP) is a common autoimmune bleeding disorder. The understanding of ITP pathogenesis is rapidly evolving. We now recognize ITP as a complex and heterogeneous syndrome that results from a combination of humoral and cell-mediated attacks on platelets peripherally and megakaryocytes in the bone marrow. Autoantibody-mediated ITP also varies in the pathway used to clear platelets, which depends on the platelet glycoprotein being targeted. Moreover, ITP patients present with variable bleeding severities and treatment responses that do not closely correlate with platelet count. A gold standard diagnostic test for ITP is lacking, and biomarkers to assess disease severity are in their infancy. This review provides an update on the immunopathogenesis of ITP and summarizes currently available tests for ITP diagnosis, prediction of disease severity, and treatment responses. Given the heterogeneous pathogenesis and clinical presentation of ITP, we highlight the need for the development of diagnostic and prognostic tests that would allow for the individualized management of a complex disease.

Equine platelet concentrate preparation and validation

Background

Development of equine platelet concentrate (PC) would aid management of cases requiring transfused platelets (PLTs), where adminstration of whole‐blood or platelet‐rich plasma (PRP) might be contraindicated.

Objectives

To test and validate a method for production of an equine PRP‐PC product.

Animals

Six healthy Thoroughbred geldings from a research herd.

Methods

In this prospective experimental study, whole blood was collected and processed through multiple centrifugation steps to yield 120 mL of PC. The PC was stored at 22°C and gently and continuously agitated. Measurements of PLT count, pH, and concentrations of glucose, lactate, electrolytes, lactate dehydrogenase (LDH), and aspartate aminotransferase (AST), as well as partial pressures of oxygen and carbon dioxide were performed on days 0, 1, 2, 3, 5, and 7. Platelet aggregometry and bacterial culture were also performed.

Results

The PC always had a PLT count of ≥550 × 10³ cells/μL. Aggregometry graph amplitude (P < .0001) and area under the curve (P < .05) significantly decreased over time. Sodium, chloride, lactate (P < .0001), and oxygen (P < .01) concentrations significantly increased over time. pH (P < .001), glucose and bicarbonate concentrations (P < .0001) significantly decreased over time. There was no significant difference in potassium concentration, PLT count, LDH and AST activities and no bacterial growth from culture.

Conclusions and Clinical Importance

The described technique yielded a PC that meets the standards of the American Association of Blood Banks for human PC.

Development and implementation of a novel immune thrombocytopenia bleeding score for dogs

Background

A method of quantifying clinical bleeding in dogs with immune thrombocytopenia (ITP) is needed because ITP patients have variable bleeding tendencies that inconsistently correlate with platelet count. A scoring system will facilitate patient comparisons and allow stratification based on bleeding severity in clinical trials.

Hypothesis/Objectives

To develop and evaluate a bleeding assessment tool for dogs, and a training course for improving its consistent implementation.

Animals

Client‐owned dogs (n = 61) with platelet counts <50,000/μL; 34 classified as primary ITP, 17 as secondary ITP, and 10 as non‐ITP.

Methods

A novel bleeding assessment tool, DOGiBAT, comprising bleeding grades from 0 (none) to 2 (severe) at 9 anatomic sites, was developed. Clinicians and technicians completed a training course and quiz before scoring thrombocytopenic patients. The training course was assessed by randomizing student volunteers to take the quiz with or without prior training. A logistic regression model assessed the association between training and quiz performance. The correlation of DOGiBAT score with platelet count and outcome measures was assessed in the thrombocytopenic dogs.

Results

Clinicians and technicians consistently applied the DOGiBAT, correctly scoring all quiz cases. The odds of trained students answering correctly were higher than those of untrained students (P < .0001). In clinical cases, DOGiBAT score and platelet count were inversely correlated (r_s = −0.527, P < .0001), and DOGiBAT directly correlated with transfusion requirements (r_s = 0.512, P < .0001) and hospitalization duration (r_s = 0.35, P = .006).

Conclusions and Clinical Importance

The DOGiBAT and assessment quiz are simple tools to standardize evaluation of bleeding severity. With further validation, the DOGiBAT may provide a clinically relevant metric to characterize ITP severity and monitor response in treatment trials.

Prevalence and disease associations in feline thrombocytopenia: a retrospective study of 194 cases

OBJECTIVES

To assess the prevalence of thrombocytopenia in a referral population of cats in the UK, to identify disease processes associated with thrombocytopenia and to assess the proportion of thrombocytopenic cats that tested positive for feline leukaemia virus or feline immunodeficiency virus.

MATERIALS AND METHODS

Retrospective analysis of medical records at a UK referral hospital. Cats were grouped by mechanism of thrombocytopenia and disease process (where known).

RESULTS

Prevalence of thrombocytopenia was 5·9%. The most common disease processes associated with thrombocytopenia were haematological or infectious disease and neoplasia; 11% of thrombocytopenic cats tested were positive for feline leukaemia virus, which is lower than reported previously. Cats presenting with unexplained haemorrhage had significantly lower platelet counts than other thrombocytopenic cats. Primary immune-mediated thrombocytopenia was less commonly diagnosed than in dogs and associated with the most severe platelet depletion in this study.

CLINICAL SIGNIFICANCE

Thrombocytopenia in cats may be more prevalent than previously reported and severe thrombocytopenia may be associated with spontaneous haemorrhage. Severe thrombocytopenia in cats appears less commonly immune-mediated than in dogs. Thrombocytopenia did not appear to be associated with retroviral infections.

First molecular detection of Babesia canis in dogs from Bosnia and Herzegovina

Babesia spp. are tick-transmitted protozoan haemoparasites of great economic, veterinary and medical impact worldwide. Herein we reported the very high prevalence of autochthonous babesiosis in symptomatic dogs from Bosnia and Herzegovina in the period from 2014 to 2016. Eighty dogs that did not leave the country were examined using parasitological and molecular analyses and babesiosis was diagnosed in 82.5% and 85.0% of them, respectively (p < 0.001). One species, Babesia canis was identified using molecular methodology (PCR and sequence analysis). Statistical analyses showed that epizootiological characteristics have no influence on the possibility of infection. Agglomerative hierarchical clustering (AHC) analyses used for comparing the symptoms and clinical signs of infection in dogs pointed out that a high degree of anemia, followed by thrombocytopenia (89%), lethargy (100%), loss of appetite (95%), fever (66%) and icterus (61%) was dominant. In addition, results of the statistical analysis performed showed that more dogs with no data of tick prophylaxis (70%) were found Babesia infected. Those results point to further intensified epizootic surveys in the territory of Bosnia and Herzegovina.

Lameness associated with tarsal haemarthrosis as the sole clinical sign of idiopathic immune-mediated thrombocytopenia in a dog

A four-year-old, male Cocker Spaniel was presented for investigation of pelvic limb stiffness. There was palpable effusion of both tarsi, and analysis of synovial fluid from these joints indicated previous haemorrhage. After further investigation a diagnosis of idiopathic immune-mediated thrombocytopenia was made. The dog responded to treatment with prednisolone and azathioprine. To the authors’ knowledge, this is the first reported case of confirmed haemarthrosis as the sole presenting clinical sign for canine idiopathic immunemediated thrombocytopenia.

Canine nodal marginal zone lymphoma: Descriptive insight into the biological behaviour

Canine nodal marginal zone lymphoma (nMZL) is classified as an indolent lymphoma. Such lymphomas are typified by low mitotic rate and slow clinical progression. While the clinical behaviour of canine splenic MZL has been described, characterized by an indolent course and a good prognosis following splenectomy, there are no studies specifically describing nMZL. The aim of this study was to describe the clinical features of and outcome for canine nMZL. Dogs with histologically confirmed nMZL undergoing a complete staging work-up (including blood analysis, flow cytometry [FC] on lymph node [LN], peripheral blood and bone marrow, imaging, histology and immunohistochemistry on a surgically removed peripheral LN) were retrospectively enrolled. Treatment consisted of chemotherapy or chemo-immunotherapy. Endpoints were response rate (RR), time to progression (TTP) and lymphoma-specific survival (LSS). A total of 35 cases were enrolled. At diagnosis, all dogs showed generalized lymphadenopathy. One-third was systemically unwell. All dogs had stage V disease; one-third also had extranodal involvement. The LN population was mainly composed of medium-sized CD21+ cells with scant resident normal lymphocytes. Histology revealed diffuse LN involvement, referring to "late-stage" MZL. Median TTP and LSS were 149 and 259 days, respectively. Increased LDH activity and substage b were significantly associated with a shorter LSS. Dogs with nMZL may show generalized lymphadenopathy and an advanced disease stage. Overall, the outcome is poor, despite the "indolent" designation. The best treatment option still needs to be defined.

An exploratory study into factors influencing development of acute canine polyradiculoneuritis in the UK

OBJECTIVES

To investigate whether the development of acute canine polyradiculoneuritis is associated with various putative risk factors.

MATERIALS AND METHODS

Retrospective case-control study with conditional logistic regression analysis from a referral hospital population in the UK where controls were matched for year of presentation.

RESULTS

Forty-three cases were identified with acute canine polyradiculoneuritis and 86 controls were selected. Jack Russell terriers and West Highland white terriers were found to have a significantly greater odds of developing acute canine polyradiculoneuritis compared to a mixed baseline group of dogs. The odds of developing acute canine polyradiculoneuritis were greater in the autumn and winter compared to spring. Vaccination, rural/urban habitation, sex, neuter status and age were not associated with development of acute canine polyradiculoneuritis in our population of dogs.

CLINICAL SIGNIFICANCE

Breed and season were associated with development of acute canine polyradiculoneuritis. However, this is a small sample and so this observation needs confirmation in further studies and other factors may also be involved. Nevertheless, these findings may be important in further understanding the aetiopathogenesis of this condition.

Cryopreserved platelet concentrate transfusions in 43 dogs: a retrospective study (2007-2013)

OBJECTIVE

To clinically characterize a group of thrombocytopenic dogs that received cryopreserved platelet concentrate (cPC) transfusion, assess efficacy of cPC treatment in improving patient outcome, and compare treated dogs to a control population of thrombocytopenic dogs that did not receive cPC transfusions.

DESIGN

Retrospective study.

SETTING

University teaching hospital.

ANIMALS

Eighty-six client-owned dogs (43 in treatment group, 43 in control group).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Medical records of thrombocytopenic dogs that received cPC transfusions and those of thrombocytopenic dogs that did not receive cPC (control population) from January 2007 through March 2013 were reviewed. Dogs receiving cPC were statistically more likely than controls to have a platelet trigger for cPC transfusion (P = 0.01), lower platelet count (P = 0.009) and hematocrit at presentation (P = 0.001), and lower hematocrit after cPC (P = 0.02). Although there was a statistically significant increase in platelet count from pre- to post-cPC transfusion (P = 0.002), cPC was not found to be effective in improving clinical bleeding or increasing survival compared to the control group. No other characteristics were statistically different between groups. No dogs receiving cPC had an acute transfusion reaction during hospitalization.

CONCLUSIONS

In the population described in this study, cPC was not found to increase survival, but was well tolerated. Controlled, prospective studies are necessary to determine indications for and efficacy of cPC transfusions.

Prospective diagnostic accuracy evaluation and clinical utilization of a modified assay for platelet-associated immunoglobulin in thrombocytopenic and nonthrombocytopenic dogs

BACKGROUND

No diagnostic tests reliably distinguish primary immune-mediated thrombocytopenia (pIMT) from other causes of thrombocytopenia.

OBJECTIVES

The purpose of the study was to evaluate diagnostic sensitivity and specificity using modified direct and indirect platelet-associated immunoglobulin (PAIg) assays and reticulated platelets (RP) by flow cytometry for the classification of thrombocytopenic dogs and differentiating pIMT.

METHODS

Platelets were isolated from plasma samples of thrombocytopenic dogs and nonthrombocytopenic healthy and ill dogs. For direct PAIg, they were analyzed by flow cytometry after incubation with anti-human amylase fluorescein isothiocyanate (FITC, negative control), anti-canine IgG-FITC, anti-canine IgM-FITC, and anti-human CD61-conjugated fluorochrome (AF647). For indirect PAIg, platelets from normothrombocytic dogs were incubated with thrombocytopenic dog plasma and analyzed similar to direct PAIg. RP percentages were determined based on forward light scatter vs thiazole orange fluorescence.

RESULTS

Seventy-five thrombocytopenic dogs, 16 nonthrombocytopenic ill dogs, and 24 healthy dogs were evaluated. Diagnostic sensitivity and specificity utilizing direct IgG was 29.4% and 75.9%, respectively; when combining direct/indirect assays (IgG/IgM), it was 76.5% and 65.5%, respectively, for distinguishing pIMT. For RP, no significant difference between pIMT and sIMT was noted. RP > 8% with positive PAIg had a sensitivity of 94% and specificity of 27.6% for distinguishing pIMT. There was a significant difference in platelet concentration and CD61% staining between control and pIMT.

CONCLUSIONS

The combined modified assays resulted in fair diagnostic sensitivity and specificity for the diagnosis of pIMT. The modification of the immunoglobulin assays improved diagnostic accuracy; however, a single panel to accurately classify thrombocytopenia remains elusive.

Evaluation of the risks of chemotherapy in dogs with thrombocytopenia

Thrombocytopenia is commonly encountered in veterinary oncology. Currently, there are no standard guidelines regarding the administration of chemotherapy to the patients with thrombocytopenia. This observational epidemiological cohort study aimed to determine whether thrombocytopenic dogs were at increased risk of gastrointestinal adverse effects (vomiting, diarrhoea, inappetence) or haemorrhage following administration of standard doses of chemotherapy. The adverse effects following 77 prospectively identified episodes of thrombocytopenia (platelet count, <200 000 µL^-1 ) were compared with the adverse effects experienced in a retrospective cohort (platelet count >200 000 µL^-1 ), and evaluated by statistical analysis. Overall, there was no statistically significant difference in the incidence of gastrointestinal adverse effects or haemorrhage between thrombocytopenic and control dogs. The control group of dogs with lymphoma were statistically more likely to experience vomiting as an adverse effect of chemotherapy (P = 0.028). The results presented here showed no evidence for an increased risk of gastrointestinal adverse effects or haemorrhage in thrombocytopenic dogs after receiving standard doses of chemotherapy.

Canine pemphigus foliaceus with concurrent immune-mediated thrombocytopenia

A 3 yr old wirehaired fox terrier was presented to his primary care veterinarian with fever, thrombocytopenia, and generalized crusting dermatitis. The skin lesion had progressed for at least 18 days, and thrombocytopenia had developed 3 days before presentation. Histopathology and direct immunofluorescence studies of the skin were consistent with pemphigus foliaceus (PF). Immunofluorescence revealed immunoglobulin G deposition around the keratinocytes in the stratum spinosum. A diagnosis of immune-mediated thrombocytopenia (IMT) was confirmed by the presence of platelet surface-associated immunoglobulin using flow cytometry. Systemic immunosuppressive therapy with cyclosporine and azathioprine was effective, and the dog survived for >2 years from the initial presentation. IMT is rarely associated with PF. This appears to be the first detailed report of a definitive diagnosis of concurrent PF and IMT in a dog. The authors' findings indicate that canine PF could be complicated by hematologic immune-mediated diseases such as IMT.

Platelet volume and plateletcrit in dogs with presumed primary immune-mediated thrombocytopenia

Background

Mean platelet volume (MPV) and plateletcrit (PCT) are indices used in evaluating immune‐mediated thrombocytopenia (IMT) in humans and in dogs with congenital macrothrombocytopenia. These indices may provide clinically valuable information in acquired thrombocytopenia.

Hypothesis/Objectives

Dogs with presumed primary IMT will have increased MPV, and therefore platelet mass (PCT) will increase faster than platelet count (PLT) during recovery.

Animals

Forty‐nine dogs with automated PLT < 30,000/μL because of presumed primary IMT and hematocrit (HCT), PCT, MPV, and platelet distribution width determined from the same complete blood count (CBC), and 46 healthy controls.

Methods

Case‐control retrospective study; PLT, PCT, MPV, and platelet distribution width (PDW) were recorded from CBCs from 49 dogs, with 45 having data collected on the day of presentation. Fifteen were confirmed to have attained a PLT ≥ 75,000/μL on at least 1 CBC within 15 days after admission. The PCT equivalent to a PLT of 75,000/μL (assuming an average MPV) was calculated for comparison with PLT in terms of time to achieve a threshold of platelet mass by the 2 measures.

Results

Mean platelet volume was higher in IMT dogs (17.3 fl) than the reference population (10.5 fl) (P < .0001). The PDW was not significantly different among the groups. The median time for PCT to reach threshold in confirmed responders was faster (3 days) compared with PLT (4 days).

Conclusions and Clinical Importance

Immune‐mediated thrombocytopenia is characterized by increased MPV. Time to achieve a threshold PCT tended to be shorter than PLT, suggesting that PCT may be a useful platelet parameter for monitoring dogs with IMT.

Use of fresh platelet concentrate or lyophilized platelets in thrombocytopenic dogs with clinical signs of hemorrhage: a preliminary trial in 37 dogs

OBJECTIVE

To examine the safety and feasibility of using lyophilized platelets (LYO) and fresh platelet concentrate (FRESH) in bleeding thrombocytopenic dogs.

DESIGN

Preliminary prospective randomized clinical trial.

SETTING

Two private referral centers and 3 university teaching hospitals.

ANIMALS

Thirty-seven dogs with a complaint of hemorrhage associated with thrombocytopenia (platelet count <70 × 10(9) /L [70,000/μL], a hematocrit >15%, and that had received neither vincristine nor platelet-containing transfusions within 72 h of enrollment were studied.

INTERVENTIONS

Animals were randomized to receive LYO or FRESH, dosed according to weight. Physical examination, complete blood counts, and coagulation testing (prothrombin time and activated partial thromboplastin time) were performed at enrollment. Physical examinations were also performed immediately post transfusion, and at 1 and 24 h after transfusion. Complete blood counts were repeated immediately post transfusion and at 24 h. Collected data included bleeding score (BLS), response to transfusion, adverse reactions, hospitalization time, need for additional transfusions, survival to discharge, and 28-d survival.

MEASUREMENTS AND MAIN RESULTS

Twenty-two dogs received LYO and 15 received FRESH. There was no difference between groups in age, weight, BLS, platelet count, white blood cell count, hematocrit, or presence of melena. There was no difference between groups in transfusion reaction rates, the need for additional transfusions, 24-h BLS, hospitalization time, survival to discharge, or 28-d survival.

CONCLUSIONS

Transfusion of LYO was feasible and associated with a low transfusion reaction rate in this limited study of thrombocytopenic canine patients presenting with mild-to-severe hemorrhage. LYO were easy to use and provided storage advantages over FRESH. Further study of this product, including examination of efficacy and platelet life span, is warranted.

Coagulation in hepatobiliary disease

OBJECTIVE

To review the pathogenesis and clinical consequences of coagulation abnormalities accompanying hepatobiliary disorders and to highlight the need for further studies to characterize these derangements and their treatment options in small animal patients.

DATA SOURCES

Veterinary and human medical literature: original research articles, scientific reviews, consensus statements, and recent texts.

SUMMARY

The liver plays an important role in the production and clearance of many components of coagulation. A wide range of hemostatic derangements can occur in patients with hepatobiliary disease including alterations in platelet number and function, coagulation factor levels, anticoagulants, vascular endothelial function, and fibrinolysis. As these hemostatic alterations include both pro- and anticoagulation pathways, the net result is often a rebalanced hemostatic system that can be easily disrupted by concurrent conditions resulting in either clinical bleeding or thrombosis. Conventional coagulation tests are inadequate at identifying the spectrum of coagulation alterations occurring in patients with hepatobiliary disease, but their evaluation is necessary to assess bleeding risk and provide prognostic information. A paucity of information exists regarding the treatment of the coagulation derangements in small animals with hepatobiliary disease. Extrapolation from human studies provides some information about potential treatment options, but further studies are warranted in this area to elucidate the best management for coagulation abnormalities in dogs and cats with hepatobiliary disease.

CONCLUSION

Hepatobiliary disease can have profound effects on coagulation function leading to hypercoagulable or hypocoagulable states. Overall coagulation status with hepatobiliary disease depends on both the type and severity of disease and the presence of associated complications.

Treatment and predictors of outcome in dogs with immune-mediated thrombocytopenia

OBJECTIVE

To characterize the clinical course of disease and identify prognostic indicators for immune-mediated thrombocytopenia in dogs.

DESIGN

Retrospective cohort study.

ANIMALS

73 dogs treated for immune-mediated thrombocytopenia at the Foster Hospital for Small Animals at the Tufts Cummings School of Veterinary Medicine and the Tufts Veterinary Emergency Treatment and Specialties Hospital.

PROCEDURES

Medical records from the period of January 2002 through June 2008 were reviewed to identify dogs with a diagnosis of immune-mediated thrombocytopenia. Data collected included signalment, clinical signs, results of initial diagnostic tests, treatment, complications, and survival duration.

RESULTS

Dog ages ranged from 5 months to 15 years (median, 8.1 years). Cocker Spaniels were overrepresented, compared with their distribution in the entire hospital population during the same period. Sixty-one of the 73 (84%) dogs survived to discharge. Seven (11 %) of those dogs were lost to follow-up. Five of the remaining 54 (9%) dogs had a relapse of the disease. The presence of melena or high BUN concentration at admission to the hospital was significantly correlated with a decreased probability of survival.

CONCLUSIONS AND CLINICAL RELEVANCE

Immune-mediated thrombocytopenia is a serious yet treatable disease, which may have a lower rate of recurrence than previously reported. The presence of melena or high BUN concentration in the study suggested a poor prognosis for affected dogs.

Immunophenotype predicts survival time in dogs with chronic lymphocytic leukemia

BACKGROUND

Chronic lymphocytic leukemia (CLL) is a hematologic disorder in dogs, but studies on prognostic factors and clinical outcome are lacking. In people, several prognostic factors have been identified and currently are used to manage patients and determine therapy.

OBJECTIVES

The aim of the study was to determine if the immunophenotype of neoplastic cells predicts survival in canine CLL.

DESIGN

Retrospective study.

ANIMALS

Forty-three dogs with CLL.

PROCEDURES

Records of dogs with a final diagnosis of CLL were reviewed. For each included dog, a CBC, blood smear for microscopic reevaluation, and immunophenotyping data had to be available. Data on signalment, history, clinical findings, therapy, follow-up, as well as date and cause of death were retrieved.

RESULTS

Seventeen dogs had B-CLL (CD21+), 19 had T-CLL (CD3+ CD8+), and 7 had atypical CLL (3 CD3- CD8+, 2 CD3+ CD4- CD8-, 1 CD3+ CD4+ CD8+, and 1 CD3+ CD21+). Among the variables considered, only immunophenotype was associated with survival. Dogs with T-CLL had approximately 3-fold and 19-fold higher probability of surviving than dogs with B-CLL and atypical CLL, respectively. Old dogs with B-CLL survived significantly longer than did young dogs, and anemic dogs with T-CLL survived a significantly shorter time than dogs without anemia.

CONCLUSIONS

Although preliminary, results suggested that immunophenotype is useful to predict survival in dogs with CLL. Young age and anemia are associated with shorter survival in dogs with B-CLL and T-CLL, respectively.