Primary immune-mediated thrombocytopenia in a cat

Area of Science:

• Veterinary Internal Medicine
• Immunology
• Hematology

Background:

• Immune-mediated thrombocytopenia (ITP) is a rare but serious condition in cats.
• Diagnosis involves identifying anti-platelet antibodies and ruling out secondary causes.
• Chronic intermittent haematuria can be a presenting sign.

Observation:

• A young female Somali cat presented with chronic intermittent haematuria and petechiae.
• Severe thrombocytopenia and megakaryocyte hyperplasia were identified.
• Direct marrow immunohistochemistry detected anti-megakaryocyte autoantibody (Immunoglobulin G).

Findings:

• A diagnosis of primary immune-mediated thrombocytopenia was made after excluding secondary causes.
• Initial immunosuppressive therapy with prednisolone, azathioprine, and vincristine was ineffective.
• Thrombocytopenia resolved following a switch to dexamethasone therapy.

Implications:

• Dexamethasone may be a more effective treatment for feline primary immune-mediated thrombocytopenia than other immunosuppressants.
• This case highlights the importance of thorough investigation for ITP in cats presenting with haematuria.
• Further research into feline ITP treatment protocols is warranted.