Thrombocytopaenia

Decreased Production:

  • Aplastic anemia
  • Leukemia
  • Myelodysplastic syndromes
  • Congenital bone marrow failure syndromes (e.g., Fanconi anemia)
  • Nutritional deficiencies (folate, vitamin B12)
  • Viral infections (EBV, CMV, HIV, hepatitis, parvovirus B19)

Increased Destruction:

  • Immune-mediated:
    • Idiopathic thrombocytopenic purpura (ITP)
    • Heparin Induced Thrombocytopaenia (HIT)
    • Systemic lupus erythematosus (SLE)
    • Evans syndrome
  • Thrombotic microangiopathies:
    • Thrombotic thrombocytopenic purpura (TTP)
    • Hemolytic uremic syndrome (HUS)
  • Infections:
    • Sepsis
    • Malaria
    • Dengue
  • Medications (e.g., antibiotics (HUS), valproate, methotrexate, heparin)

Sequestration

  • Splenomegaly: Enlarged spleen sequesters platelets, reducing their number in circulation.
    • Liver diseases (e.g., cirrhosis)
    • Portal hypertension
    • Lymphoproliferative disorders
    • Spherocytosis
    • Thalassaemia

4. Dilutional

  • Massive Transfusions: Large volumes of transfused blood or fluids can dilute platelets.
    • Trauma
    • Major surgeries

5. Miscellaneous Causes

  • Pregnancy: Gestational thrombocytopenia, HELLP syndrome (hemolysis, elevated liver enzymes, low platelet count)
  • Chronic Alcoholism: Direct bone marrow toxicity and nutritional deficiencies
  • Hereditary Conditions: Wiskott-Aldrich syndrome, Bernard-Soulier syndrome, May-Hegglin anomaly