Major causes of thrombocytopenia in infants and children

• Epstein-Barr virus
• Cytomegalovirus
• Bacterial sepsis
• Parvovirus
• Varicella
• Rickettsia
• Dengue virus

Nutritional deficiencies

• Folate
• B12
• Iron

Acquired bone marrow failure

• Aplastic anemia
• Myelodysplastic syndromes
• Myelosuppressive/myeloablative therapies (eg, chemotherapy, radiation)

Infiltrative bone marrow diseases

• Leukemia or lymphoma
• Metastatic cancer
• Infectious granuloma
• Storage disease

Genetic causes of impaired thrombopoiesis^*

• Wiskott-Aldrich syndrome/X-linked thrombocytopenia
• Inherited bone marrow failure syndromes
  • Fanconi anemia
  • Dyskeratosis congenita
  • Shwachman-Diamond syndrome
  • Congenital amegakaryocytic thrombocytopenia
• Thrombocytopenia with absent radii syndrome
• Amegakaryocytic thrombocytopenia with radioulnar synostosis
• Familial platelet disorder with predisposition to hematologic malignancy
• Bernard-Soulier syndrome
• MYH9-related disorders
• Paris-Trousseau syndrome
• X-linked thrombocytopenia with dyserythropoiesis

• Immune thrombocytopenia (ITP)
• Neonatal alloimmune thrombocytopenia
• Drug-induced thrombocytopenia
• Systemic autoimmune disorders and immune dysregulation syndromes (secondary ITP)
  • Systemic lupus erythematosus
  • Autoimmune lymphoproliferative syndrome
  • Antiphospholipid antibody syndrome
  • Common variable immunodeficiency
  • DiGeorge (22q11.2 deletion) syndrome

Platelet activation and consumption

• Microangiopathic disorders
  • Hemolytic-uremic syndrome
  • Thrombotic thrombocytopenic purpura
  • Disseminated intravascular coagulation
• Major surgery or trauma
• Type 2B or platelet-type (pseudo) von Willebrand disease
• Heparin-induced thrombocytopenia
• Vascular anomalies, including Kasabach-Merritt syndrome

Mechanical destruction

• Extracorporeal therapies (eg, cardiopulmonary bypass)

• Hypersplenism

• Massive transfusion
• Large intravenous fluid resuscitation