Felis ISSN 2398-2950

Thrombocytopenia

Contributor(s): Vetstream Ltd

Introduction

  • Thrombocytopenia is apparently rare in the cat (incidence 1%) - but may be under-diagnosed.
  • It is a clinical sign and NOT a diagnosis - investigation is directed at identifying underlying cause.
  • Cause: decreased production or increased utilization of platelets.
  • Signs: may be no clinical signs or signs of bleeding.
  • Diagnosis: hematology.
  • Treatment: depends on cause.
  • Prognosis: depends on cause.
    Print off the owner factsheet on Thrombocytopenia (decreased platelet count)   Thrombocytopaenia (decreased platelet count) to give to your client.

Pathogenesis

Etiology

Decreased platelet production

Increased platelet destruction

Increased platelet utilization

  • Disseminated intravascular coagulopathy.
  • Severe hemorrhage (theoretical cause of thrombocytopenia unlikely in practice).
    In about 20% cases no underlying pathology is identified.

Predisposing factors

General

  • Recent vaccination.

Pathophysiology

  • Low platelet counts may cause spontaneous bleeding.
  • < 30% cats showed spontaneously bleeding with thrombocytopenia.
  • Platelets produced by megakaryocytes in the marrow.
  • Megakaryopoiesis takes 4 weeks and circulating platelets have a lifespan of 1 week under normal circumstances.
  • Suppression of platelet precursors in marrow   →   drop in number of platelets released to circulation.
  • Short lifespan of platelets means that thrombocytopenia may be seen before other cytopenias in marrow disease.
  • In DIC generalized intravascular coagulation consumes platelets Disseminated intravascular coagulation.
  • Immune mediated destruction of platelets can be primary or secondary:
    • Primary  →  production of antibodies against platelets.
    • Secondary  →  platelets destroyed due to cross reaction of antibodies against other things, eg drugs.

Timecourse

  • May be chronic before clinical signs recognized.

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.
  • Ellis J, Bell R, Barnes D C, Miller R (2018) Prevalence and disease associations in feline thrombocytopenia: a retrospective study of 194 cases. JSAP 59(9), 531-538 PubMed.
  • Tasker S, Cripps P J & Mackin A J (2001) Evaluation of methods of platelet counting in the cat. JSAP 42 (7), 326-332 PubMed.
  • Tasker S, Mackin A J & Day M J (1999) Primary immune-mediated thrombocytopenia in a cat. JSAP 40 (3), 127-131 PubMed.
  • Hodson S & Mackin A (1998) Thrombocytopenia in the cat. Feline Focus 8, 2-7.
  • Jordan H L, Grindem C B & Breitschwerdt E B (1993) Thrombocytopenia in cats - a retrospective study of 41 cases. JVIM (5), 261-265 PubMed.
  • Boyce J T, Kociba G J, Jacobs R M et al (1986) Feline leukemia induced thrombocytopenia and macrothrombocytosis in cats. Vet Pathol 23 (1), 16-20 PubMed.


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