Immune-mediated thrombocytopenic purpura: Difference between revisions

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==Definition==
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==Background==
   
 
*Acquired autoimmune bleeding disorder characterized by autoimmune autobody-mediated destruction of platelets
 
*Acquired autoimmune bleeding disorder characterized by autoimmune autobody-mediated destruction of platelets
   
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===Etiology===
==Differential Diagnosis==
 
   
 
*Primary
 
*Primary
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==Management==
 
==Management==
   
=== Acute management ===
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===Acute management===
   
 
*Only needs treatment if platelets lower than 30 or if bleeding
 
*Only needs treatment if platelets lower than 30 or if bleeding

Latest revision as of 19:27, 21 September 2020

Background

  • Acquired autoimmune bleeding disorder characterized by autoimmune autobody-mediated destruction of platelets

Etiology

Investigations

  • CBC
    • Mean platelet volume can suggest high platelet turnover
  • Peripheral blood film
  • HIV and HCV testing
  • Additional
    • Abdo ultrasound for splenomegaly and liver disease
    • Rh status
    • DAT for Evan's syndrome
    • Quantitative immunoglobulins
    • Hep B testing
    • H. pylori, if at risk
    • Antiphospholipid antibodies
    • ANA, anti-dsDNA
    • Thyroid tests
    • vWF testing (for type 2B vWD)
    • Bone marrow biopsy

Management

Acute management

  • Only needs treatment if platelets lower than 30 or if bleeding
  • First-line:
    • Steroids
      • Prednisone 1-2mg/kg/day x3weeks then taper (70-80% response but high relapses over next 10 years)
      • Dexamethasone 40mg/d po x4days ever 2-4 weeks, repeated for 3-6 cycles (90% response)
    • IVIg 1-2g/kg x1-2 days, if refractory to steroids or requires rapid treatment
    • Anti-D if Rh positive and has a spleen
  • Second-line:
    • Splenectomy
      • Ensure vaccinated for Hib, Strep pneumo, and N. meningitidis
    • Rituximab
    • Thrombopoeitin agonists: eltrombopag or romiplostim
    • Immunosuppressive therapies: azathioprine, cyclosporin A, cyclophosphomide, danazol, dapsone, mycofenolate mofetil, vina alkaloids
  • Third-line:
    • Almtuzumab, chemotherapy, stem cell transplant
  • For life-threatening bleed:
    • IVIG 1g/kg, repeated once more if platelets remain below 50 the next day
    • Pulse steroids: methylprednisolone 30mg/kg IV daily x2-3 days)
    • Tranexamic acid 1G IV q6h
    • Platelet transfusion
    • Emergency splenectomy
    • Last-ditch: recombinant factor VIIa 90mcg/kg IV q2h
      • High risk for clotting