Immune thrombocytopenic purpura (peds)

This page is for pediatric patients. For adult patients, see: Immune thrombocytopenic purpura.

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

Thrombocytopenia

Decreased production

• Marrow infiltration (tumor or infection)
• Viral infections (rubella, HIV)
• Marrow suppression (commonly chemotherapy or radiation)
• Congenital thrombocytopenia
  • Fanconi anemia
  • Alport syndrome
  • Bernand Soulier
• Vitamin B12 and/or folate deficiency

Increased platelet destruction or use

• Idiopathic thrombocytopenic purpura
• Thrombotic Thrombocytopenic Purpura (TTP)
• Hemolytic Uremic Syndrome (HUS)
• Disseminated Intravascular Coagulation (DIC)
• Viral infections (HIV, mumps, varicella, EBV)
• Drugs (heparin, protamine)
• Postransfusion or Posttransplantation
• Autoimmune destruction (SLE or Sarcoidosis)
• Mechanical destruction
  • Artificial valves
  • ECMO
• HELLP syndrome
• Excessive hemorrhage
• Hemodialysis, extracorporeal circulation
• Splenic Sequestration
  • Occurs in Sickle cell disease and Cirrhosis

Drug Induced

• sulfa antibiotics, ETOH, ASA, thiazide diuretics/furosemide

Comparison by Etiology

	ITP	TTP	HUS	HIT	DIC
↓ PLT	Yes	Yes	Yes	Yes	Yes
↑PT/INR	No	No	No	+/-	Yes
MAHA	No	Yes	Yes	No	Yes
↓ Fibrinogen	No	No	No	No	Yes
Ok to give PLT	Yes	No	No	No	Yes

Evaluation

Workup

• CBC

Diagnosis

• 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 RhoGAM if significant bleeding or if preparing for procedure
  • Severe bleeding, non-life threatening: Platelet transfusion if needed. Methylprednisolone, IVIG and/or RhoGAM 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.