Immune thrombocytopenic purpura

• What is immune thrombocytopenic purpura?


  Autoimmune disease

  Characterised by a reduction in circulatory platelets

  Type II hypersensitivity reaction

  Spleen produces antibodies directed against glycoprotein IIb/IIIa or Ib-V-IX complex
• What are the RFs for immune thrombocytopenic purpura?


  Often triggered by a viral infection or following immunisation

  Secondary ITP (rare), can be due to:

  • autoimmune conditions (SLE)
  • infections (H.pylori & CMV)
  • meds
  • lymphoproliferative disorders
• What are the signs & symptoms of immune thrombocytopenic purpura?


  Easy or excessive bruising (purpura)

  Superficial bleeding into skin -> petechiae (usually on the lower legs)

  Prolonged bleeding from cuts

  Spontaneous bleeding from gums or nose

  Blood in urine or stools

  Unusually heavy menstrual flow in females
• What are the DDx of immune thrombocytopenic purpura?


  Aplastic anaemia

  Leukaemia

  Thrombotic thrombocytopenic purpura (more severe condition)
• What are the Inx of immune thrombocytopenic purpura?


  Obs

  Full Hx & examination

  Bloods (FBC, CRP, blood film)

  Bone marrow biopsy -> only required if the case appears atypical or there is suspicion of malignancy
• What is the management of immune thrombocytopenic purpura?


  Generally conservative

  Tranexamic acid (TXA) -> may be used to help blood clotting, particularly in menorrhagia

  Steroids can be used for persistent cases

  IV immunoglobulin

  Splenectomy -> may be used in cases the prove refractory for 12-24 months

  Platelet transfusions (only if life-threatening bleeding) - this would increase the rate of platelet destruction

  Ibuprofen should be avoided in children with ITP
• What are the possible complications of immune thrombocytopenic purpura?


  Significant bleeds

  Intracranial haemorrhage

  ^ Typically occur when platelet counts are less than 20
• Immune thrombocytopenic purpura is generally self-resolving within weeks to months without intervention. However, up to 1 in 5 children will follow a chronic course.
• Pathophys - immune thrombocytopenic purpura


  Exact aetiology is unknown

  Increased platelet destruction in spleen by anti-platelet autoantibodies directed against platelet membrane antigens -> autoantibodies suppress megakaryocyte precursors -> inhibition of platelet production -> T cell mediated destruction of platelets & megakaryocyte precursors in bone marrow -> thrombocytopenia

  Autoantibody production is thought to be caused by dysregulated CD4+ T cells reacting to platelet surface glycoproteins