Immune-mediated Hemolytic Anemia and Thrombocytopenia in the Dog: A retrospective study of 55 cases diagnosed from 1979 through 1983 at the Western College of Veterinary Medicine

All recognized cases (n = 55) of immune-mediated hemolytic anemia and immune-mediated thrombocytopenia in dogs presented to the Western College of Veterinary Medicine from 1969 through 1983 were reviewed. Specific areas of concern were: association with other conditions, therapeutic response, prognosis, relapse rate and final outcome. Of these 55 cases, 19 were immune-mediated hemolytic anemia, 26 were immune-mediated thrombocytopenia and 10 were both immune-mediated hemolytic anemia and thrombocytopenia. Females were slightly over-represented and the mean age was 6.4 years. Therapy consisted of various combinations of immuno-suppressive drugs and in some cases, whole blood transfusion and splenectomy. No firm conclusions could be made regarding therapeutic efficacy, as a result of variation in treatment protocol and the occasional unavailability of follow-up data. Well over half of all cases were diagnosed as idiopathic. Precipitating factors or diseases most frequently implicated in secondary immune-mediated thrombocytopenia or hemolytic anemia were: recent vaccination, drug therapy, obstetrical complications, stress, recent viral infection and neoplasia. Twice as many cases of immune-mediated hemolytic anemia were seen in the cooler months (October to March), although this could not be related to antibody class or thermal reactivity. Immune-mediated thrombocytopenia both as a single disease and combined with immune-mediated hemolytic anemia had no seasonal incidence. History, clinical findings and hematological and clinical chemistry findings were consistent with data previously reported, with the exception of icterus, which appeared to be of higher incidence than most reports, being present in almost 50% of immune-mediated hemolytic anemia cases. Just over half of all dogs survived, although the survival rate was highest for immune-mediated hemolytic anemia, followed closely by immune-mediated thrombocytopenia and lowest for the combined disease. Immune-mediated thrombocytopenia most frequently ran a relapsing course requiring long-term or intermittent therapy.     

Cytologic evaluation of primary and secondary myelodysplastic syndromes in the dog

Myelodysplastic syndromes are a heterogeneous group of acquired primary and secondary alterations of hematopoietic stem cells that result in cytopenias in blood and cytologic features of dysplasia in blood and/or bone marrow. To better understand the cytologic features that would permit differentiation of primary and secondary forms of myelodysplasia, we reviewed 267 consecutive bone marrow reports from dogs. These reports indicated that 34 dogs (12.7%) had dysgranulopoiesis, dyserythropoiesis, and/or dysthrombopoiesis in >10% of granulopoietic cells, erythroid cells, and/or megakaryocytes, respectively. Thirteen dogs had primary myelodysplastic syndromes, and 21 had secondary myelodysplastic syndromes. Of the 13 dogs with primary myelodysplasia, 4 were subclassified as myelodysplastic syndrome with refractory anemia (MDS-RA), and 9 were subclassified as myelodysplastic syndrome with excess blasts (MDS-EB). Secondary conditions associated with dysplasia in the bone marrow included malignant lymphoma (n = 5), myelofibrosis (n = 3), immune-mediated thrombocytopenia (n = 4), immune-mediated hemolytic anemia (n = 5), multiple myeloma with melphalan administration (n = 1), pyometra with estrogen administration (n = 1), polycythemia vera (n = 1), and thrombopathia (n = 1). MDS-RA was characterized by <5% myeloblasts in bone marrow, normal granulocyte maturation ratio, increased erythroid maturation ratio, and dysplastic changes in >15% of erythroid cells. MSD-EB was characterized by >/=5% myeloblasts in bone marrow, high granulocyte maturation and erythroid maturation ratios, >/=32% dysplastic granulocytes, and the presence of small atypical immature myeloid cells. Secondary myelodysplastic syndromes were characterized by <5% myeloblasts in bone marrow, variable granulocyte maturation and erythroid maturation ratios, and variable dysplastic features. These results indicate that morphology alone cannot be used to distinguish primary and secondary myelodysplastic syndromes in dogs.     

Application of therapeutic plasma exchange in dogs with immune-mediated thrombocytopenia

Therapeutic plasma exchange (TPE) is an emerging treatment for dogs with immune-mediated diseases, but reports for treatment of immune-mediated thrombocytopenia (IMT) are lacking. These case reports illustrate the application of centrifugal TPE in 4 dogs with IMT. All dogs presented with severe hemorrhage requiring ≥1 blood transfusions, were unresponsive to conventional treatment or both. Dogs were treated with 3 sequential centrifugal TPE sessions, totaling 4.0 to 4.9 total plasma volumes exchanged per dog. In 3 dogs, TPE was associated with improvement in clinical manifestations of bleeding and platelet count in combination with immunosuppressive drugs. One dog was euthanized after 3 treatments because of persistent severe thrombocytopenia and hemorrhage. Preliminary observations indicate that TPE is safe and may be a useful adjunct in the management of IMT that is severe or refractory to traditional treatment.     

Presumptive hemophagocytic syndrome associated with immune-mediated anemia in two Miniature Dachshunds

This report describes the cases of two Miniature Dachshunds who were suspected to have immune-mediated hemolytic anemia (IMHA) and were treated with immunosuppressive therapy. However, progression of anemia, increases in C-reactive protein (CRP) and total-bilirubin (T-Bil) levels, splenomegaly, transition to nonregenerative anemia, and thrombocytopenia occurred after the treatment. Splenectomy and bone-marrow aspirations were performed subsequently. Both dogs were diagnosed with hemophagocytic syndrome (HPS) associated with IMHA. Unfortunately, they died 9 and 6 days later. These findings indicate that some cases of refractory IMHA have the pathogenicity of HPS. HPS should be included as a differential diagnosis of refractory IMHA concurrent with thrombocytopenia. Continuously elevated CRP and T-Bil levels may be helpful indicators in the detection of HPS associated with IMHA.     

Platelet Dysfunction Associated With Immune-Mediated Thrombocytopenia in Dogs

The effect of antiplatelet antibody on in vitro platelet function was investigated in 15 dogs with immune-mediated thrombocytopenia (ITP). Platelet aggregation was assessed after addition of serum from healthy dogs (n = 5) or dogs with ITP (n = 15) to platelet-rich plasma from a healthy donor dog. The aggregation responses to adenosine diphosphate, thrombin, and collagen/epinephrine were measured as the maximum aggregation observed after 2 minutes. In 13 of 15 dogs with ITP, maximal aggregation was significantly inhibited in response to ADP, thrombin, or collagen/epinephrine. The slope of the aggregation curve was decreased after addition of serum from 9 of 15 patients. A polyclonal rabbit anti—dog platelet antiserum induced inhibition of aggregation with all 3 agonists.
Serum from control dogs neither inhibited nor activated platelet aggregation. Aggregation experiments were repeated with all 3 agonists after addition of patient immunoglobulin (lg)G or IgG from a healthy dog to platelet-rich plasma. The IgG fraction from 9 of 10 dogs with ITP suppressed platelet aggregation. The IgG fraction from polyclonal rabbit anti—dog platelet antiserum inhibited platelet aggregation with all agonists. These results suggest that many canine ITP patients have circulating antibodies that, in addition to causing platelet destruction, may cause platelet dysfunction.     

Detection of Antiplatelet Antibody With a Platelet Immunofluorescence Assay

An indirect platelet immunofluorescence assay (PIFA) was developed for detection of circulating antiplatelet antibody in dogs with suspected immune-mediated thrombocytopenia (ITP). The PIFA was performed on 10 healthy dogs with normal platelet counts; 76 thrombocytopenic dogs, 20 of which were suspected of having ITP; and 18 dogs with other diseases and normal platelet counts. All normal dogs had negative test results. Fourteen (70%) of 20 dogs suspected of having ITP had positive test results. Fifteen of the remaining 56 thrombocytopenic dogs had positive test results, 9 had cancer and 6 had other immune-mediated diseases including systemic lupus erythematosus (SLE). In this study, the PIFA assay seemed to be more sensitive (70%) than the megakaryocyte immunofluorescence assay (41 %) in the diagnosis of ITP. Of the 9 PIFA-positive dogs with neoplasia, 6 had lymphoproliferative disorders. The PI FA was positive in 5 of 18 diseased dogs with normal platelet counts. There was an inverse relationship between the platelet count and the intensity of fluorescence in the PIFA-positive dogs. We conclude that the PIFA is a sensitive screening method for detecting circulating antiplatelet antibody.     

Morphological evaluation of canine platelets on Giemsa- and PAS-stained blood smears

The morphology of canine platelets (changes in size, shape, staining characteristics, degree of activation and clump formation, distribution of granules, appearance of vacuoles on Giemsa-stained smears) was investigated in 20 healthy control and 181 diseased dogs. In the group of the sick dogs 84 animals suffered from disorders affecting directly the haematological parameters or the haematopoietic organs such as bleeding, thymic haemorrhage, haemolytic disorders, lymphoma, immune-mediated thrombocytopenia, and other 97 dogs were affected by other diseases (hepatopathy, nephropathy, hepatic, splenic or intestinal neoplasm, skin diseases, diabetes mellitus, Cushing's syndrome, sepsis). The alterations found in platelet morphology were not specific for any disorder. The most common platelet abnormalities were polychromasia and the presence of giant platelets. These changes occurred in a high number in disorders accompanied by bleeding or haemolysis. Anisocytosis was the most frequent finding in hepatic, splenic or intestinal neoplasms and in certain endocrinopathies. Microcytosis was observed in immune-mediated thrombocytopenia, hepatic neoplasms and endocrine disorders. Extreme platelet activation was common in haemolysis, hepatopathies, neoplastic diseases and sepsis. Vacuolisation was present in thymic haemorrhage, pancreatitis, diabetes mellitus and Cushing's syndrome. A new morphologic phenomenon, i.e. a ring-like formation of granules, was described in the cytoplasm of the platelets both in healthy and diseased animals. In addition, two forms of pathologic granulation were also described for the first time in Giemsa-stained blood smears: the pseudonuclear and the spot-like formation of granules, which were observed especially in disorders affecting the blood cells. The granulation and morphological characteristics of platelets on smears stained by periodic acid-Schiff reaction (PAS) were also studied. Three localisations of granulation were observed, such as peripheral, eccentric and diffuse. The ratio of PAS-positive and -negative platelets was evaluated in several diseases. Our findings support the diagnostic value of platelet evaluation by light microscopy and help clinicians/clinical pathologists to understand why morphologic changes of thrombocytes might be expected in several diseases.     

Canine idiopathic thrombocytopenia: clinical observations and long-term follow-up in 54 cases

Idiopathic thrombocytopenia purpura (ITP) was diagnosed in 54 dogs. Bleeding was associated with platelet counts less than or equal to 30,000/mm3, and occurred most frequently at mucosal surfaces and in the skin. Other hematologic changes were variable, the most common being regenerative anemia with leukocytosis. Bone marrow examination revealed variable megakaryocyte numbers, but hyperplasia was most commonly observed. Results of the platelet factor 3 test were positive in only 7 of 25 dogs so tested. Treatment included various combinations of corticosteroid, vincristine, cyclophosphamide, and splenectomy. The dogs could be classified into 4 groups on the basis of the course of disease: (1) 14 dogs that died or were euthanatized during the first episode of thrombocytopenia, (2) 17 dogs that recovered after a single episode of thrombocytopenia (acute ITP), (3) 8 dogs in which thrombocytopenia recurred over a period of up to 8 months before recovering (acute, recurrent ITP), and (4) 15 dogs that experienced repeated episodes of ITP for periods of up to 8 years (chronic ITP).     

Cytologic evaluation of benign and malignant hemophagocytic disorders in canine bone marrow

Abstract: Canine hemophagocytic disorders were studied to better understand the cytologic features that differentiate benign and malignant disease. Of 286 canine clinical bone marrow reports evaluated retrospectively, 13 (4.5%) noted at least 3% hemophagocytic macrophages. Macrophages comprised between 6% and 44% of nucleated bone marrow cells. Clinical diagnoses for dogs with hemophagocytic disorders included malignant histiocytosis (n = 2), myelodysplastic syndromes (n = 4), round cell neoplasia (n = 2), immune-mediated disorders (n = 2), and idiopathic hemophagocytic syndrome (n = 3). Differentiation of benign and malignant forms of histiocytosis was problematic. Two dogs with a diagnosis of hemophagocytic syndrome had macrophages with atypical features similar to those described for malignant histiocytosis. Furthermore, only 2 of 11 dogs with presumably benign hemophagocytic disorders had exclusively mature macrophages in bone marrow. Other dogs had variable numbers of large reticular-type cells characterized by lacy chromatin, anisocytosis, anisokaryosis, and prominent and/or multiple nucleoli. On the basis of these results, cytomorphologic evaluation of bone marrow alone may not be adequate to consistently differentiate benign and malignant forms of hemophagocytic disorders.     

Therapy of Immune Mediated Thrombocytopenia

Fifteen dogs with immune mediated thrombocytopenia (IMT) were studied retrospectively. All dogs had a thrombocyte count below 50,000/microliters when response to therapy was studied. Platelet counts greater than 50,000/microliters were present in all dogs within 2-9 days of initiating medical therapy. Eight dogs experienced a single episode of thrombocytopenia and seven dogs relapsed over the following 5 to 24 months. Clinical parameters from dogs that experienced a single episode of IMT were compared with data from dogs that relapsed to determine whether any information would identify dogs that were prone to relapse. Signalment, severity of thrombocytopenia, and time to achieve a platelet count above 50,000/microliters were found not to differ (P greater than 0.05) between these two groups. Five of the seven dogs with relapsing IMT were splenectomized after 2 to 4 episodes (mean, 2.8 +/- 0.8) of thrombocytopenia over 2 to 14 months. The postoperative progress of these five dogs was followed for 6 to 17 months. Platelet counts were sustained above 200,000/microliters in 4/5 after splenectomy and it was possible to discontinue medical therapy in these dogs. In comparison, the 2 relapsing IMT cases that were not splenectomized continued to require intermittent immunosuppressive therapy. We conclude that signalment and routine pretreatment laboratory test results are not useful in distinguishing dogs with relapsing IMT from those that will experience one episode of IMT. Seemingly, splenectomy is useful in the management of dogs with relapsing IMT.     

Anti-erythrocyte antibodies and disease associations in anemic and nonanemic dogs

BACKGROUND: Flow cytometry has been used to detect anti-red blood cell (RBC) antibodies in dogs with immune-mediated hemolytic anemia (IMHA), but the prevalence of anti-RBC antibodies in anemic and nonanemic dogs with a variety of different diseases has not been assessed previously. HYPOTHESIS: We hypothesized that anti-RBC antibodies would be more common in anemic dogs and in dogs with immune-mediated disorders and cancer. ANIMALS: Blood samples from 292 dogs were analyzed prospectively by flow cytometry for anti-RBC antibodies. METHODS: Blood samples from 147 anemic and 145 nonanemic dogs were evaluated by flow cytometry to detect surface-bound immunoglobulin (Ig) G and IgM antibodies on RBC. Disease associations with RBC antibodies were determined, as was the correlation between disease status and the percentage of Ig(+) RBC. The specificity and sensitivity of flow cytometry and clinical variables for the diagnosis of IMHA were compared by Bayesian analysis. RESULTS: Anemic dogs were significantly more likely to be positive for anti-RBC antibodies (IgG, IgM, or both) than nonanemic dogs. Anemic dogs also had significantly higher percentages of Ig(+) RBC than nonanemic dogs, whereas dogs with IMHA had significantly higher percentages of Ig(+) RBC than dogs with all other diseases. Dogs with IMHA, infectious diseases, and immune-mediated thrombocytopenia were significantly more likely to have anti-RBC antibodies than dogs with other medical or surgical diseases. CONCLUSIONS: Anemic dogs with immune-mediated diseases and infectious diseases were at the highest risk for the development of anti-RBC antibodies, and flow cytometry for the detection of IgG on RBC was highly sensitive and specific for the diagnosis of IMHA.     

Ehrlichiosis in anemic, thrombocytopenic, or tick-infested dogs from a hospital population in South Brazil

Ehrlichia canis has a worldwide distribution, but clinical manifestations may vary geographically. We selected 129 dogs to determine prevalence of ehrlichiosis in dogs with anemia, thrombocytopenia, or ticks presented to a Veterinary Teaching Hospital in South Brazil. Of the 129 dogs, 68 carried the brown dog tick (Rhipicephalus sanguineus), 61 had thrombocytopenia (platelet count <150,000/microl), and 19 had anemia (PCV < 22%). Twenty dogs fulfilled more than one inclusion criteria. Ehrlichiosis was diagnosed by positive amplification of ehrlichial DNA by PCR using primers ECC and ECB that amplify a sequence of the 16S rRNA gene. Presence of E. canis was confirmed by cleavage of the amplified DNA using endonucleases HaeIII and AvaI. Fourteen of 68 (21%) dogs with ticks had ehrlichiosis, whereas 12 of 61 (20%) dogs presented with thrombocytopenia and 4 of 19 (21%) anemic dogs had ehrlichiosis. Similar results were obtained in dogs with thrombocytopenia and anemia (one of eight positive) and in dogs with thrombocytopenia and ticks (two of seven positive). All four dogs with anemia and ticks, and the dog that fulfilled all inclusion criteria yield no amplification of ehrlichial DNA by PCR. Based on our results, one in each five dogs infested by the brown dog tick, with anemia or thrombocytopenia had ehrlichosis. Contrary to widespread believe, ehrlichiosis was not the main cause for thrombocytopenia in our region.     

Ehrlichia and Babesia infections in dogs in The Netherlands

A retrospective study was performed at the Department of Clinical Sciences of Companion Animals at Utrecht University amongst 75 dogs diagnosed with a Babesia canis and/or an Ehrlichia canis infection. The majority of the dogs had visited an endemic area (most often the Mediterranean area or the Dutch Antilles), but two dogs became infected with Babesia in the Netherlands. Babesia infections were associated with a stay in an endemic area and an incubation period that are both significantly shorter (less than 3 months) than those for Ehrlichia and co-infections (more than 3 months). Reasons for the owner to seek veterinary attention (lethargy, anorexia, fever), findings from the physical examination (pale mucous membranes, hepato-/splenomegaly) and laboratory results (anemia, thrombocytopenia, hypo-albuminemia) were highly aspecific, making serology or PCR mandatory for diagnosing infections. Antigenic stimulation by the parasite sometimes resulted in immune-mediated diseases such as immune-mediated hemolytic anemia, thrombocytopenia, glomerulonefritis, and polyarthritis and in the case of ehrlichiosis in hypergammaglobulinemia. Specific therapy (imidocarb-diproprionate and/or doxycycline) was necessary, and because combined infections were common, it was considered appropriate to administer both drugs while the definitive diagnosis was being established. The prognosis was reasonably good, with almost half of all patients showing no clinical signs after treatment, although Babesia and co-infections were associated with a significantly longer survival sometimes resulted than Ehrlichia infections.     

Evaluation of platelet activation in canine immune-mediated haemolytic anaemia

Objectives : To establish whether heightened platelet activation is a common feature of canine immune-mediated haemolytic anaemia, and to evaluate the hypothesis that platelet activation plays a role in the pathogenesis of thromboembolism. Methods : Using whole-blood flow-cytometric analysis, the proportion of activated platelets and platelet-leucocyte aggregates in blood samples from 14 dogs with immune-mediated haemolytic anaemia and 14 healthy dogs was calculated. General linear models with binomial errors were used to compare groups. Results from the immune-mediated haemolytic anaemia-affected dogs were then correlated with established risk factors for thromboembolism in canine immune-mediated haemolytic anaemia, D-dimer concentration and antithrombin activity. Results : There was a strong correlation between platelet activation and severe thrombocytopenia, with heightened platelet activation being observed predominantly in severely thrombocytopenic dogs. Clinical Significance : Dogs with immune-mediated haemolytic anaemia, particularly those with concurrent severe thrombocytopenia, are likely to have heightened platelet activation, which may play a role in the pathogenesis of thromboembolism.     

A retrospective study of canine pancytopenia

To better define the incidence and causes of canine pancytopenia, we retrospectively evaluated the results of complete blood counts submitted to the University of Minnesota Veterinary Teaching Hospital during a 1-year period. Pancytopenia was defined as packed cell volume < 36%, total leukocyte count < 6,000/microliter or total segmented neutrophil count < 3,000/microliter, and platelet count < 200,000/microliter. Of 4,560 complete blood counts, 110 (2.4%) samples from 51 dogs met the criteria for pancytopenia. Eleven different disease processes were identified. These included chemotherapy-associated pancytopenia (n=22), parvovirus infection (n=5), malignant histiocytosis (n=5), idiopathic aplastic anemia (n=3), sepsis (n=3), myelodysplastic syndrome (n=3), immune-mediated hematologic disease (n=3), lymphoblastic leukemia (n=2), ehrlichiosis (n=2), estrogen toxicity (n=2), and multiple myeloma (n=1). Malignant histiocytosis and idiopathic aplastic anemia occurred more frequently than was expected. Doxoruicin was the chemotherapeutic agent associated with pancytopenia. Hematologic recovery and patient survival time varied with the cause of pancytopenia; therefore, a specific diagnosis was essential for establishing prognosis. Differentiation among causes of pancytopenia requires a systemic approach that includes elimination of infectious and drug-induced causes, and examination of bone marrow aspiration and core biopsy specimens.     

Development of a sensitive immunoradiometric assay for detection of platelet surface-associated immunoglobulins in thrombocytopenic dogs

OBJECTIVE: To develop a direct assay to measure platelet surface-associated immunoglobulins (PSAIg) in dogs and to determine whether the assay is useful in the diagnosis of immune-mediated thrombocytopenia (IMT). ANIMALS: 20 healthy dogs were used to develop reference intervals, and 23 dogs with IMT and 17 with non-IMT were used to evaluate the clinical use of this assay. PROCEDURE: After optimization of platelet collection and assay conditions, concentrations of PSAIg were measured, using radiolabeled staphylococcal protein A (SpA) and polyclonal antibodies against canine IgG (anti-gamma) and IgM (anti-micro). Concentrations of PSAIg were expressed as the percentage of radiolabeled immunoglobulin detector bound. RESULTS: Cut-off values (mean + 3 SD) were as follows: SpA, 1.1%; anti-gamma, 1.3%; and anti-micro, 3.5%. Values greater than these cut-off values were considered positive. Values determined by use of radiolabeled SpA for all dogs with IMT were greater than the cut-off value; values were considered high positives (> 5 times cut-off value) for 22 of these 23 dogs. Although 9 of 17 dogs with non-IMT also had PSAIg concentrations greater than the cut-off value, values were considered high positives for only 3 of these 9 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: The immunoradiometric assay developed is a reliable and sensitive method to detect PSAIg in dogs. However, to obtain accurate results, optimum temperature, time, and storage conditions must be used. Detection of increased concentrations of PSAIg in dogs presumed to have non-IMT should alert clinicians to reconsider an immune-mediated basis for the thrombocytopenia.     

Diagnosis of microthrombocytosis and immune-mediated thrombocytopenia in dogs with thrombocytopenia: 68 cases (1987-1989).

The mean platelet volume (MPV) was evaluated in 68 dogs with thrombocytopenia attributable to various causes. Platelet size was high or low in some dogs. The most clinically useful observation was that low MPV (microthrombocytosis) was a specific indicator of immune-mediated thrombocytopenia (IMT) in these thrombocytopenic dogs. All but one case of microthrombocytosis (MPV less than 5.4 fl) was found in dogs with IMT. Microthrombocytosis was detected in 17 of 31 dogs with IMT and appeared at the onset of the disease. Macrothrombocytosis (MPV greater than 9.4 fl) indicated active thrombopoiesis, but was not unique to any disease category. Macrothrombocytosis was detected in 18 of 31 dogs with IMT, 3 of 17 dogs with disseminated intravascular coagulation, and 3 of 9 dogs with primary bone-marrow disease.     

Splenectomy as an adjunctive treatment for dogs with immune-mediated hemolytic anemia: ten cases (2003–2006)

Objective – To describe the patient population, disease severity, and outcome in dogs with immune-mediated hemolytic anemia (IMHA) that underwent splenectomy. To compare presurgical and postsurgical data.
Design – Retrospective case series.
Setting – Emergency clinic/referral hospital.
Animals – Ten dogs diagnosed with IMHA.
Interventions – Splenectomy in addition to standard medical management for IMHA.
Measurements – Medical records of 10 dogs with IMHA, in which a splenectomy was performed were reviewed. The population was analyzed with regards to physical and clinicopathologic data, severity, treatment, and outcome. Outcome was defined as survival at 30 days, percentage of dogs on medications at 30 days, and number of relapses documented by 30 days. The presurgical and postsurgical PCV and transfusion requirements were documented and compared for each dog.
Results – Nine of 10 dogs survived to 30 days. Four of the 9 that survived were not on any immunosuppressive medications. There were no relapses during the 30 days. The 3-day postsplenectomy PCVs were significantly higher than presplenectomy. The number of transfusions administered postsplenectomy was significantly less than those administered presplenectomy.
Conclusion – The use of splenectomy may be associated with an improved outcome in dogs with IMHA.     

A retrospective study of the incidence and the classification of bone marrow disorders in the dog at a veterinary teaching hospital (1996-2004)

BACKGROUND: An 8-year retrospective study was conducted to evaluate the prevalence and the classification of canine bone marrow disorders in a clinical pathology service at a university referral hospital. ANIMALS: Dogs evaluated for bone marrow disorders at a veterinary teaching hospital. HYPOTHESIS: A better understanding of the spectrum and the prevalence of canine bone marrow disorders can be achieved with a multiyear retrospective study. METHODS: Bone marrow aspirate smears, core biopsy specimens, and case records from 717 dogs were reviewed. RESULTS: Bone marrow specimens were first categorized based on the presence or the absence of a primary bone marrow disorder. Nondysplastic and nonmalignant pathologic changes were placed into 14 subcategories. Frequently observed pathologic disorders included nonregenerative immune-mediated anemia, pure red cell aplasia, bone marrow necrosis, myelofibrosis, and hemophagocytic syndrome. Dysmyelopoiesis (n = 61) was subcategorized into myelodysplastic syndromes (n = 27), and congenital (n = 1) and secondary (n = 33) dysmyelopoiesis. One hundred twenty-six cases of neoplasia were divided into acute leukemia (n = 46), chronic leukemia (n = 7), stage 5 malignant lymphoma (n = 28), multiple myeloma (n = 25), malignant histiocytosis (n = 11), metastatic mast-cell tumor (n = 3), sarcoma (n = 5), and carcinoma (n = 1). CONCLUSIONS AND CLINICAL IMPORTANCE: This study provides a general indication of the spectrum and the prevalence of canine bone marrow disorders at a referral center in North America.     

Immune‐mediated hemolytic anemia and severe thrombocytopenia in dogs: 12 cases (2001–2008)

Objective – To identify and characterize the syndrome of immune‐mediated hemolytic anemia (IMHA) with concurrent severe thrombocytopenia (≤15.0 × 10⁹ platelets/L; [15.0 × 10³ platelets/μL]), and to evaluate prognostic factors, clinicopathologic findings, complications, treatment, outcome, and survival of dogs with this hematologic disorder. Design – Retrospective, observational study. Setting – Veterinary teaching hospital. Animals – Twelve client‐owned dogs with IMHA and severe thrombocytopenia (≤15.0 × 10⁹ platelets/L; [15.0 × 10³ platelets/μL]), without evidence of overt disseminated intravascular coagulation. Interventions – The following data were recorded and analyzed from the electronic medical record: signalment, history, concurrent diseases, clinical signs at presentation, clinicopathologic data, diagnostic testing, radiographic findings, treatment modalities, length of hospitalization, complications, and clinical outcome. All dogs were treated with immunosuppressive doses of corticosteroids. Measurements and Main Results – Twelve dogs were identified with the diagnosis of IMHA and severe thrombocytopenia; of these, 9 (75%) survived, 3 (25%) were euthanized, and none died. Dogs that survived were significantly younger than nonsurvivors (P=0.03). There were no specific clinical signs or therapies associated with survival. Conclusions – Dogs in this study had a mortality rate similar to reported rates for dogs with either disease alone. Overall, younger dogs were more likely to survive. No association between different treatment modalities and overall survival was identified.