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Immune Thrombocytopenic Purpura

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Immune Thrombocytopenic Purpura, Idiopathic Thrombocytopenic Purpura, ITP

  • See Also
  1. Thrombocytopenia
  2. Drug induced Thrombocytopenia
  • Definitions
  1. Immune Thrombocytopenic Purpura
    1. Premature splenic destruction of Antibody-covered Platelets, while other hematopoetic cell lines remain unaffected
  • Epidemiology
  1. Incidence: 10 cases per 100,000
  2. Children comprise 50% of cases
    1. Most common isolated Thrombocytopenia cause in children
    2. Peak onset between ages 2 to 4 years
  • 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
  • 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
  • Findings
  • Signs and Symptoms
  1. Mild symptoms (often asymptomatic)
    1. Purpura
    2. Mild Splenomegaly in 5 to 10% of cases
    3. Bleeding complications
      1. Associated with severe Thrombocytopenia (Platelet Count <30,000 per uL)
  2. Absent signs
    1. No fever, lethargy, pallor or weight loss
    2. No bone or Joint Pain
    3. No Lymphadenopathy
    4. No Hepatomegaly
  • Labs
  1. See Thrombocytopenia
  2. No specific test defines Immune Thrombocytopenic Purpura (diagnosis of exclusion)
    1. Exclude other Thrombocytopenia Causes first
  3. Complete Blood Count with Platelets
    1. Other than Thrombocytopenia, remainder of blood count is typically normal
    2. Platelet Count
      1. Acute, rapid drop in Platelet Count
      2. Platelet Count is typically 50k to 100k
      3. May decrease to levels at risk for life threatening bleeding (<10k/uL)
  • Management
  • General
  1. See Thrombocytopenia for hospitalization criteria
  2. Hematology Referral best within first 72 hours of diagnosis
  3. Outpatient Management Indications (most patients)
    1. Platelet Count >20k/uL AND
    2. Minimal to no bleeding AND
    3. Otherwise symptomatic
  4. Emergent management
    1. Indications for urgent or emergent management (uncommon)
      1. Platelet Count <10,000/uL
      2. Serious Hemorrhage
      3. Urgent or emergent surgery required
    2. Platelet Transfusion
      1. Platelet Transfusion at dosing 2-3 fold greater than usual dose
      2. Platelet survival increases with IgG infusion immediately after Platelet Transfusion
  • Management
  • Hematology
  1. First-Line
    1. Corticosteroids
      1. Indicated for severe Thrombocytopenia
        1. Typically indicated with Platelet Count <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)
  2. 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 ITP >1 year and 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]
  • 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
  • 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 (2022) Am Fam Physician 106(3): 288-98 [PubMed]
  5. Gauer (2012) Am Fam Physician 85(6): 612-22 [PubMed]
  6. George (1996) Blood 88:3-40 [PubMed]
  7. Jones (2024) Am Fam Physician 110(1): 58-64 [PubMed]
  8. Neunert (2019) Blood Adv 3(23): 3829-66 [PubMed]
  9. Souid (1995) Clin Pediatr 34:487-94 [PubMed]