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

BackgroundCurrent 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.ObjectivesTo 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.AnimalsSeventeen 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.MethodsData 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.ResultsSix 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 ImportanceSplenectomy 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.     

Systemic neosporosis in a dog treated for immune‐mediated thrombocytopenia and hemolytic anemia

A 4‐year‐old male Toy Poodle was presented to the Small Animal Veterinary Hospital of the Faculty of Veterinary Medicine of the Autonomous University of Mexico (FMVZ, UNAM) because of depression, lethargy, and hemorrhages involving several areas of the skin and around the eyes. Hematology data and a bone marrow analysis suggested hemolytic anemia and immune‐mediated thrombocytopenia. The dog was treated with prednisone, and after one month the hematology variables improved. However, the dog's clinical condition inexplicably worsened and it was euthanized. On necropsy, there were no relevant findings. However, in histology, multifocal lymphoplasmacytic and histiocytic meningoencephalitis and necrosis, and a protozoan cyst in the cerebellum were identified. In addition, moderate multifocal lymphoplasmacytic and necrotizing pancreatitis, hepatitis, myocarditis, and diffuse lymphoplasmacytic enteritis were observed. Immunohistochemistry of the cerebellum, liver, pancreas, and intestine with a specific antibody against Neospora caninum confirmed the diagnosis of systemic neosporosis. The systemic neosporosis in this dog was most likely caused by reactivation of latent parasites due to prednisone administration during the one month of treatment. It should be kept in mind that in dogs being treated with immunosuppressants for immune‐mediated conditions, opportunistic parasites, such as Toxoplasma gondii and N caninum, can be reactivated from a latent state, as it probably happened in the present case.     

Successful treatment of presumptive immune mediated thrombocytopenia and dermatitis with azathioprine in a pregnant mare

This report describes the successful treatment of immune‐mediated thrombocytopenia (IMTP) with azathioprine in a pregnant mare that had been refractory to therapy with dexamethasone. The interesting features of this case included the presence of dermatitis, a clinical presentation not previously associated with IMTP in the equine literature and the maintenance of pregnancy and delivery of a healthy normal foal despite immunosuppressive therapy with azathioprine during critical stages of early gestation.     

Pseudo‐hypoproteinemia in a hyperbilirubinemic dog with immune‐mediated hemolytic anemia

A 10‐year‐old spayed female Miniature Poodle was presented to the University of Georgia veterinary teaching hospital for evaluation of lethargy, vomiting and anorexia of 4 days' duration. Physical examination, history and a minimum database led to a diagnosis of immune‐mediated hemolytic anemia accompanied by marked hyperbilirubinemia. Refractometric protein determination was within the reference interval, whereas the biuret method indicated hypoproteinemia. This discrepancy was attributed to interference of bilirubin and biliverdin with the spectrophotometric read‐out of the biuret total protein assay. The albumin concentration, determined by bromcresol green, and refractometric total protein were less affected by this interference.     

Presumed immune‐mediated hemolytic anemia in two foals with Rhodococcus equi infection

Objective – To describe the clinical presentation, case management, and outcome in 2 foals with Rhodococcus equi infection associated with presumptive severe immune‐mediated hemolytic anemia. Series Summary – Two foals diagnosed with R. equi pneumonia on the basis of tracheal wash cultures, thoracic radiographs, and thoracic ultrasonography were concurrently diagnosed with hemolytic anemia. Both foals required whole blood transfusions, and were treated with the antimicrobial combination of rifampin and a macrolide (eg, clarithromycin, erythromycin, or azithromycin). Dexamethasone was used to prevent further hemolysis in both foals, and to treat acute lung injury/acute respiratory distress syndrome in 1 of the foals. Both foals survived, and required prolonged antimicrobial therapy. New or Unique Information Provided – Although extra‐pulmonary disorders are commonly diagnosed in foals infected with R. equi, hemolytic anemia is rarely described. Dexamethasone is considered the treatment of choice for immune‐mediated hemolytic anemia, but may be contra‐indicated in foals with severe bacterial infections. In these foals, a relatively low dose and short duration of dexamethasone was utilized in an attempt to minimize immune suppression, although early discontinuation in 1 foal precipitated a second hemolytic crisis.     

Comparison of platelet count recovery with use of vincristine and prednisone or prednisone alone for treatment for severe immune-mediated thrombocytopenia in dogs

OBJECTIVE: To evaluate the effect of prednisone alone, compared with a combination of prednisone and vincristine, on platelet counts in bleeding dogs with severe primary immune-mediated thrombocytopenia (IMT). DESIGN: Prospective case study. ANIMALS: 24 dogs with severe primary IMT PROCEDURE: All dogs received immunosuppressive doses of prednisone (1.5 to 2 mg/kg [0.7 to 0.9 mg/lb] of body weight, PO, q 12 h). In addition, 12 dogs received a single dose of vincristine (0.02 mg/kg [0.01 mg/lb], IV). Platelet count, transfusion requirement, and outcome were monitored. A response was defined as an increase in platelet count to > or = 40,000/microl. Dogs in the prednisone group that failed to respond received 1 dose of vincristine on day 7. RESULTS: Dogs that received prednisone and vincristine had a significantly faster increase in platelet count to > or = 40,000 platelets/microl than dogs that received prednisone alone (mean +/- SD, 4.9 +/- 1.1 vs 6.8 +/- 4.5 days, respectively). A similarly rapid response was observed in dogs that received vincristine on day 7 after treatment with prednisone alone failed. Furthermore, duration of hospitalization was reduced in the vincristine group, compared with the prednisone group (5.4 +/- 0.3 vs 7.3 +/- 0.5 days, respectively). No adverse effects attributable to vincristine were observed in any dog. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of combined vincristine and prednisone is associated with more rapid increase in platelet numbers and shortened duration of hospitalization in dogs with IMT, compared with use of prednisone alone. Early use of vincristine seems warranted in dogs with severe primary IMT.     

Treatment of primary immune‐mediated hemolytic anemia with mycophenolate mofetil in two cats

Objective – To describe the use of oral mycophenolate mofetil (MMF) as an adjunctive therapy in 2 cats with primary immune‐mediated hemolytic anemia. Case Series Summary – Two cats suffering from presumptive primary immune mediated hemolytic were treated with MMF as part of their treatment regimens. Both cats had improved complete blood counts following therapy. New or Unique Information Provided – This is the first reported use of oral MMF as adjunctive treatment for cats with immune‐mediated hemolytic anemia. Outcome was favorable in both cats and no adverse effects were noted from the MMF.     

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.