Immune-mediated thrombocytopenia in a 4-month-old German shepherd dog

A 4-month-old, intact female, German shepherd dog exhibited a painful abdomen and lethargy. Immune-mediated thrombocytopenia was diagnosed and initial remission attained using prednisone. Upon relapse, prednisone and vincristine together were unsuccessful in achieving remission. This case is unique due to the young age of the dog.     

Immune-mediated thrombocytopenia associated with Angiostrongylus vasorum infection in a dog

A three-year-old weimaraner was presented with lethargy, anorexia, neck pain and a soft fluctuant swelling in the thoracic inlet. A cough had been noted previously. Clinical examination revealed tachycardia, tachypnoea, pallor and a large subcutaneous swelling, with bruising, suggestive of a haematoma in the thoracic inlet. Thoracic radiographs revealed a cranial mediastinal mass which had the ultrasonographic appearance of fluid, and there was also a marked generalised interstitial lung pattern. Routine haematology revealed severe anaemia and thrombocytopenia, although coagulation tests were within normal limits. A diagnosis of immune-mediated thrombocytopenia was however made on the basis of a positive antiplatelet antibody test and a rapid response to prednisolone therapy. Furthermore, a tentative diagnosis of Angiostrongylus vasorum infection was suggested on the basis of clinical and radiographic findings, although no lungworm larvae were identified on faecal analysis. Despite initiating treatment with fenbendazole, the dog died suddenly. Postmortem examination revealed myocarditis, thrombosing arteritis, pneumonia and chronic membranoproliferative glomerulonephritis associated with A vasorum infection.     

Immune-mediated haemolytic anaemia and thrombocytopenia associated with Anaplasma phagocytophilum in a dog

A 10-year-old, crossbreed dog was presented with a history of severe lethargy, pyrexia and inappetence of several days' duration. Clinical examination revealed pallor of the mucous membranes, petechiae, generalised lymphadenopathy and effusions in multiple joints. Laboratory evaluation showed severe anaemia and thrombocytopenia, with positive in-saline agglutination and the presence of antiplatelet antibodies. The DNA of Anaplasma phagocytophilum, an endemic granulocytic rickettsial parasite, was detected by PCR. A poor response to doxycycline and immunosuppressive therapy with corticosteroids was seen. Euthanasia was performed after the development of disseminated intravascular coagulation. Postmortem examination demonstrated changes consistent with the development of disseminated intravascular coagulation and infection with granulocytic ehrlichiosis. This case documents the presence of canine granulocytic ehrlichiosis caused by A phagocytophilum in the U.K., and highlights the range of clinical signs and clinicopathological abnormalities that may be observed in infected dogs.     

Immune-mediated hemolytic anemia and thrombocytopenia in a foal

A one-month-old Quarter Horse filly had unilateral epistaxis, hyphema, icterus, petechial hemorrhages in the oral, nasal, conjunctival, and vulvar mucous membranes, anemia, thrombocytopenia, negative antinuclear test result, and a positive direct Coombs' test result. Megakaryocytes or cell-associated IgG (fluorescent antibody and immunoperoxidase stains) were not found in bone marrow biopsy specimens. Treatment consisted of glucocorticoids, antibiotics, and a single whole blood transfusion. The foal responded well to treatment, did not develop relapses of the disease, and was clinically normal one year after treatment.     

Immune-mediated thrombocytopenia associated with angiostrongylus vasorum infection in a Jack Russell terrier

A twenty-month-old Jack Russell terrier was presented with a four-day history of thrombocytopenia, echymotic inguinal haemorrhages, coughing and reduced exercise tolerance. Clinical examination revealed several petechial haemorrhages on the gingivae and small echymotic haemorrhages in the inguinal region, along with mild bilateral epistaxis. Haematology confirmed a platelet count of 1.0 × 10/L. Thoracic radiographs revealed a wide-spread mixed alveolar-interstitial lung pattern, apparent throughout the entire lungfield, but particularly marked within the left lung lobes. A presumptive diagnosis of immune-mediated thrombocytopenia was made and the dog was treated with vincristine and immunosuppressive doses of prednisolone. Initially anaemia developed following gastrointestinal haemorrhage; however, after symptomatic treatment the dog showed a marked clinical improvement. Evaluation for an underlying cause of the disease revealed Angiostrongylus vasorum L1 larvae on faecal analysis and treatment with fenbendazole was commenced. The dog made a full clinical recovery with all treatment was withdrawn within five weeks of diagnosis. This is the second report of immune-mediated thrombocytopenia associated with Angiostrongylus vasorum infection and it is the first to be successfully managed. The report highlights that Angiostrongylus vasorum should be considered in young dogs presented with thrombocytopenia.     

Presumptive trimethoprimsulphamethoxazole associated thrombocytopenia and anaemia in a dog

A two-year-old Scottish terrier was referred for investigation of a chronic skin problem. A diagnosis of generalised demodectic mange with a deep pyoderma was made and treatment commenced with trimethoprirn-sulphamethoxazole and amitraz washes. On the sixth week of treatment the owner reported that the dog had developed haematuria. Investigations revealed that the dog was thrombocytopenic and anaemic. Antimicrobial treatment was stopped and the platelet count returned to normal over a three week period. A diagnosis of trimethoprim-sulphamethoxazole associated thrombocytopenia was made.     

Gold-induced immune thrombocytopenia in the dog

In two seven-year studies with gold compounds in dogs of both sexes, thrombocytopenia was observed after 45 to 72 months of dosing in three of 14 and two of 14 dogs in high-dose groups that received 2.4 to 3.6 mg/kg of auranofin per day orally or 0.5 to 2.0 mg/kg of gold sodium thiomalate intramuscularly once every three days, respectively. An immune basis for the disorder was suggested by the apparent consumptive nature of the thrombocytopenia (increased bone marrow megakaryocytes and large peripheral blood platelets), the response to corticosteroid therapy and the demonstration of increased platelet-associated immunoglobulin. The latter was demonstrated with a solid phase radioimmunoassay and by electron microscopy using a staphylococcal protein A-colloidal gold conjugate. Platelet-associated immunoglobulin decreased as the platelet counts rose, and in one dog monitored over periods of steroid-induced remissions and subsequent relapses, the amount of platelet-associated immunoglobulin G correlated inversely with the platelet count (r = 0.82). These findings suggest that the long-term administration of gold compounds in dogs is associated with a dose-dependent incidence of thrombocytopenia, which is immune-mediated and similar to that associated with parenteral chrysotherapy in man. The application of tests for platelet-associated immunoglobulin to canine patients with immune thrombocytopenia should be useful in the diagnosis of the disorder in clinical practice.     

Concurrent bartonellosis and babesiosis in a dog with persistent thrombocytopenia

A 12-year-old castrated male West Highland White Terrier was referred because of recurrent episodes of collapsing. The dog was mildly anemic and severely thrombocytopenic and had high serum alanine aminotransferase activity. Infection with Bartonella vinsonii (berkhoffii) was initially diagnosed on the basis of serologic testing. Despite treatment with a series of antimicrobials and prolonged use of immunosuppressive drugs, thrombocytopenia persisted. After 5 months of treatment, Babesia canis organisms were seen during examination of a direct blood smear. The dog was treated with imidocarb dipropionate for babesiosis, after which thrombocytopenia resolved, and administration of immunosuppressive drugs was discontinued. Retrospective review of blood smears failed to identify organisms; however, polymerase chain reaction (PCR) analysis of multiple stored blood samples obtained during the 5-month period of persistent thrombocytopenia identified DNA of B. canis vogeli. Babesiosis may cause persistent, unexplained thrombocytopenia in dogs that are not anemic. A PCR assay can facilitate a diagnosis of babesiosis when organisms are not evident or when serologic testing fails to detect Babesia-specific antibodies.     

Use of danazol for treatment of corticosteroid-resistant immune-mediated thrombocytopenia in a dog

A routine health screen of a 7 1/2-year-old female Beagle participating as a control in a long-term study revealed thrombocytopenia. Immune thrombocytopenia was diagnosed on the basis of regenerative bone marrow findings (high number of megakaryocytes) and evidence of antiplatelet antibodies. Treatment with prednisone at dosages up to 1 mg/kg of body weight every 12 hours resulted in limited improvement, with relapses of severe thrombocytopenia thwarting attempts to taper the corticosteroid, and was further complicated by side effects of the drug. Addition of danazol to the treatment regimen (5 mg/kg, q 12 h) resulted in remission of the thrombocytopenia within 2 weeks and permitted the dosage of prednisone to gradually be reduced and discontinued. Associated with this response was a decrease in platelet-associated IgG to values comparable with control samples.     

Immune-mediated hemolytic anemia in a horse

An 18-year-old Quarter Horse gelding was determined to have immune-mediated hemolytic anemia after detection of autoagglutination of RBC spherocytosis as well as a positive direct Coombs test result. A lack of response to treatment with corticosteroids necessiated the administration of cyclophosphamide and azathioprine. The anemia resolved after treatment with chemotherapeutic drugs.     

Glucocorticoid-dependent hypoadrenocorticism with thrombocytopenia and neutropenia mimicking sepsis in a Labrador retriever dog

Glucocorticoid-deficient hypoadrenocorticism (GDH) with immune-mediated-neutropenia (IMN) and -thrombocytopenia (IMT) were diagnosed in a 3-year-old Labrador retriever dog. Glucocorticoid-deficient hypoadrenocorticism is rare and diagnostically challenging as clinical signs and laboratory abnormalities are often nonspecific. Immune-mediated cytopenias and other autoimmune disorders, as part of an autoimmune polyglandular syndrome have been reported with hypoadrenocorticism in humans. This is the first reported case of hypoadrenocorticism and bicytopenia in a dog.