Platelet Abnormalities

Disease associated with platelet abnormalities

Primary Thrombocytopenic Disease

• The aetiology of primary thrombocytopenic disease is often uncertain.
  • It is therefore also known as idiopathic thrombocytopenia.
  • The cause may be automimmune - see Immune Mediated Thrombocytopaenia.
• Although the bone marrow contains adequate normal megakaryocytes, there is a reduced peripheral blood thrombocyte count.
• Usually seen in young animals.

Secondary Thrombocytopenic Disease

• Secondary thrombocyopaenic disease is fairly common in adult and older domestic animals.
• Associated with diseases which cause bone marrow depression.
• The bone marrow is depleted or devoid of megakaryocytes, and there is a nil or markedly reduced peripheral blood thrombocyte count.
• Secondary thrombocyopenic disease is seen in the following conditions:
  1. Severe viral infections.
     • For examople, ICH, feline panleucopenia, mucosal disease, swine fever.
  2. Severe protozoal infections.
     • For example, in the UK, Haemobartonella may be a cause.
  3. Plant intoxications.
     • For example, bracken, kale, or ragwort poisoning.
  4. Drug-induced conditions.
     • High doses of oestrogens and salicylate.
     • Prolonged use of phenyl butazone.
  5. bone marrow neoplasia.
     • For example, lymphosarcoma or myeloid leukaemia.
  6. Radiation.
     • May cause damage to the bone marrow if it is severe and generalised.
  7. Other miscellaneous causes.
     • Severe bacterial infections.
       • For example, Staphylococci, and those Gram -ve bacteria producing endotoxins (e.g. Pseudomonas or Salmonella spp.).
     • Liver disease.

Thrombocytopathia

• A rare inherited condition.
• Recorded in the dog.
• Characterised by defective thrombocyte formation.
  • Poor adhesiveness.
  • Poor aggregations.
  • Poor platelet factor release.