Low platelet count (Normal is between 150,000 to 450,000 per microlitre)

Platelet life span is normally approx. 5 days, with continual renewal

Causes can be divided into reduced production in the bone marrow or increased destruction

Problems with Production

• Sepsis
• B12 or folic acid deficiency
• Liver failure causing reduced thrombopoietin production in the liver
• Leukaemia, HL and NHL
• Myelodysplastic syndrome,
• cytotoxic drugs, radiation

Problems with Destruction

• Medications (sodium valproate, methotrexate, isotretinoin, antihistamines, proton pump inhibitors)
• Alcohol
• Immune thrombocytopenic purpura
• Thrombotic thrombocytopenic purpura
• Heparin-induced thrombocytopenia
• Haemolytic-uraemic syndrome - most commonly associated with Escherichia coli  0157:H7 infection which causes diffuse diarrhoea
• Infections - Dengue, Zika virus, malaria, HIV/AIDS, miliary TB, Covid-19

Epidemiology: