Immune thrombocytopenic purpura (peds)

Background

• Also known as immune thrombocytopenia (ITP)
• Autoantibodies to platelet membrane antigens clear platelets and limit production
• Can be primary or secondary (medications, systemic illness, infection)
• Hallmark is isolated thrombocytopenia
• Primary peak is in early childhood (2-5 years) with a smaller peak in adolescence
• ITP is a diagnosis of exclusion

Clinical Features

• Usually well appearing without constitutional symptoms
• May have a preceding systemic illness
• May have exposure to recent vaccinations (particularly MMR) or drugs known to cause thrombocytopenia: Heparin, Quinidine, Phenytoin, Sulfa drugs, Valproate and Vancomycin
• May have bleeding, but this may be absent
  • Most have dry bleeding consisting of petechiae, purpura, and ecchymoses
  • Can see mucosal bleeding
  • Severe or intracranial bleeding are rare

Differential Diagnosis

• See image

Workup

• Platelet count of < 100,000/microL is usually the only finding on a CBC
  • Usually < 30,000/microL.
• Remainder of the CBC is typically normal, unless there is significant bleeding (Hgb could be low)
• Peripheral blood smear shows fewer than normal platelets and increased mean platelet volume (due to younger, larger platelets/megakaryocytes)

Management

• Consult pediatric hematologist
• Avoid activity that could increase risk of trauma
• Avoid NSAIDs and anticoagulants
• Therapy is based on degree of bleeding
  • Low-risk bleeding: Watchful waiting
  • Moderate to high-risk bleeding: IVIG or Rho(D)immune globulin if significant bleeding or if preparing for procedure
  • Severe bleeding, non-life threatening: Platelet transfusion if needed. Methylprednisolone, IVIG and/or Rho(D)immune globulin for up to 4 days. Possibly Romiplostim (thrombopoietin receptor agonist) or TXA.
  • Life threatening bleeding: Platelet transfusion, methylprednisolone x 3-4 days, IVIG x 1-3 days.

Disposition

• Low-risk patients may be discharged with short-term follow up
• Moderate to high-risk patients or those with severe bleeding should be admitted

See Also

• ITP

References

Duncan, Ellen. Immune Thrombocytopenia. PEM GUIDES. 7th edition. NYU Langone Health; 2020: 459-462.