Immune Thrombocytopenic Purpura

Sep 16, 2019 admin DA LIỄU, HUYẾT HỌC & UNG THƯ, NHI KHOA 0

Immune Thrombocytopenic Purpura

Aka: Immune Thrombocytopenic Purpura, Idiopathic Thrombocytopenic Purpura, ITP

II. Epidemiology

  1. Incidence: 10 cases per 100,000
  2. Children comprise 50% of cases
    1. Most common Thrombocytopenia cause in children
    2. Peak onset between ages 2 to 4 years

III. Pathophysiology

  1. IgG Antibody develops against platelet membrane antigen
  2. Acute Idiopathic Thrombocytopenic Purpura
    1. Acute onset follows Viral Exanthem or viral Infection
    2. Occurs in otherwise healthy patients
  3. Chronic Idiopathic Thrombocytopenic Purpura
    1. Insidious onset in patient with immune disorder
    2. More common onset in teenage girls

IV. Causes: Secondary Immune Thrombocytopenic Purpura

  1. Lymphoproliferative Disorders or Myelodysplastic Syndrome
    1. Evaluate in all patients over age 60 years with Immune Thrombocytopenic Purpura
  2. Systemic Lupus Erythematosus
  3. Antiphospholipid Syndrome
  4. Graves Disease
  5. Sarcoidosis
  6. HIV Infection
  7. Epstein-Barr Virus Infection (EBV or mononucleosus)
  8. Cytomegalovirus (CMV)
  9. Varicella-Zoster Virus
  10. Hepatitis C Virus

V. Signs and Symptoms

  1. Purpura
  2. Bleeding complications
    1. Associated with severe Thrombocytopenia (Platelet Count <30,000 per uL)
  3. Mild Splenomegaly in 5 to 10% of cases
  4. Absent signs
    1. No fever, lethargy, pallor or weight loss
    2. No bone or Joint Pain
    3. No Lymphadenopathy
    4. No Hepatomegaly

VI. Labs

  1. Platelet Count drops rapidly

VII. Management: First-Line Management

  1. Corticosteroids
    1. Indicated for severe Thrombocytopenia
      1. Typically indicated with Platelet Count <50,000 per uL (especially <30,000 per uL)
    2. Platelets increase within a week of starting Corticosteroids
    3. Dosing
      1. Methylprednisolone 30 ml/kg/day over 20-30 min up to 1 g/day IV OR
      2. Prednisone 1-1.5 mg/kg orally daily
  2. Intravenous Immune globulin (IV IG)
    1. Dose: 1 g/kg/day for 2-3 days
  3. Rituximab (Rituxan)

VIII. Management: Emergent management

  1. Indications for urgent or emergent management (uncommon)
    1. Serious Hemorrhage
    2. Urgent or emergent surgery required
  2. Treatment
    1. Platelet Transfusion at dosing 2-3 fold greater than usual dose

IX. Management: Refractory cases

  1. Anti-D Immune globulin
    1. May be used in Rh Positive patients
    2. May be considered as alternative to Corticosteroids
  2. Thrombopoietin receptor agonist
  3. Splenectomy
    1. Indicated if corticosterioids and Immunoglobulin Are ineffective at maintaining adequate Platelet Counts
    2. Safe and effective (however subjects patient to lifelong Asplenia risk)
    3. May be preferred in younger patients
    4. Gadenstatter (2002) Am J Surg 184:606-10 [PubMed]

X. Course

  1. Children: Acute Idiopathic Thrombocytopenic Purpura
    1. Less severe in children
    2. Recovery within 6 to 12 months for 80-90% of children
    3. Most cases resolve within weeks
  2. Adults
    1. More chronic, insidious course than for adults

XI. References

  1. Merrill and Gillen (2016) Crit Dec Emerg Med 30(3): 3-8
  2. Blanchette (2000) Semin Hematol 37(3):299-314 [PubMed]
  3. Bolton-Maggs (2000) Arch Dis Child 83(3):220-2 [PubMed]
  4. Gauer (2012) Am Fam Physician 85(6): 612-22 [PubMed]
  5. George (1996) Blood 88:3-40 [PubMed]
  6. Souid (1995) Clin Pediatr 34:487-94 [PubMed]

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