Immune-mediated thrombocytopenia

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.

Diagnosis

Clinical signs

• Ecchymotic hemorrhages of retina, iris and sclera.
• Petechial hemorrhage of mucous membranes: mouth, sclera.
• Petechial hemorrhages on skin - but coat may need to be clipped to see these.

Diagnosis

Differential diagnosis

• Disseminated intravascular coagulation    .
• Bone marrow suppression by FeLV  [Feline leukemia virus disease]  , FIE  [Feline panleucopenia virus disease]  , myelophthisis, ehrlichiosis (rare in cat).
• Splenic sequestration in hypersplenism.

• Other bleeding disorders.

Outcomes

Prognosis

• Must be guarded as underlying disease is often severe.
• If underlying case can be identified and treated or response to treatment is rapid the prognosis may be favorable.

Expected response to treatment

• Cessation of spontaneous bleeding if present.
• Increasing platelet count.

Reasons for treatment failure

• Underlying disease not diagnosed or treated adequately.
• Therapy not sufficiently aggressive.