Felis ISSN 2398-2950
Immune-mediated thrombocytopenia
Synonym(s): IMTP
Contributor(s): Michael Day, Richard Squires
Introduction
- Immune-mediated thrombocytopenia (IMTP) is rare and poorly documented in the cat (in contrast to the dog).
- Cause: most cases are likely to be secondary (particularly to FeLV infection and associated neoplasia) rather than primary autoimmune thrombocytopenia (AITP).
- Signs: vague, eg anorexia, lethargy.
- Diagnosis: often presumptive, platelet count <50,000, anti-platelet antibody.
- Treatment: treat underlying condition and immunosuppression if required.
- Prognosis: guarded.
Print off the owner factsheet on Immune-mediated thrombocytopenia Immune-mediated thrombocytopaenia to give to your client.
Pathogenesis
Predisposing factors
General
Specific
Pathophysiology
- Antibody binds to platelets → early removal from circulation → clinical signs.
- Antibody (IgG or IgM) and/or complement bound to platelet membrane. Antibody-labeled cells are removed by phagocytic cells in spleen (Type II hypersensitivity) in excess of replacement by bone marrow thrombopoiesis.
- Antibody may also inhibit platelet function (dog; not documented in cat).
- Antibody may be specific for platelet membrane antigens, or for adsorbed drug or infectious agent, or membrane antigens modified or exposed by binding of such agents.
- Antibody may be specific for bone marrow precursors (megakaryocytes) leading to immune-mediated amegakaryocytic thrombocytopenia.
- May be concurrent immune-mediated hemolytic anemia Anemia: immune-mediated hemolytic , or IMTP may be part of multisystemic immune-mediated disease (systemic lupus erythematosus Systemic lupus erythematosus).
Timecourse
Diagnosis
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Treatment
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Outcomes
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Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
- Garon C L, Scott M A, Selting K A et al (1999) Idiopathic thrombocytopenic purpura in a cat. JAAHA 35 (6), 464-470 PubMed.
- Tasker S, Mackin A J & Day M J (1999) Primary immune-mediated thrombocytopenia in a cat. JSAP 40 (3), 127-131 PubMed.
- Jordan H L, Grindem C B & Breitschwerdt E B (1993) Thrombocytopenia in cats- a retrospective study of 41 cases. JVIM 7 (5), 261-265 PubMed.
- Gaschen F P, Smith Meyer B and Harvey J W (1992) Amegakarocytic thrombocytopenia and immune-mediated haemolytic anaemia in a cat. Comparative Haematology International 2 (3), 175-8 VetMedResource.
Other sources of information
- Day M J (1999) Clinical immunology of the dog and cat. London: Manson Publishing. ISBN:1 8745 4598 7.
- Smith J et al (1999) Chronic thrombocytopenia and epistaxis in a cat. Feline Practice 27 (3), 5-8.