Full Blood Count
 

Platelet Count

 
 
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Overview

  • Platelets are very small non-nucleated cells that derive from fragmentation of megakaryocytes. They play an important role in clot formation and haemostasis.
      • Normal Range

      • 150 - 400 x 10‎⁹/L

Thrombocytosis

  • Thrombosis refers to an increase in circulating platelets. This may occur due to a myeloproliferative neoplasm, a reactive increase in platelet production, or a shift in platelets from the spleen into the circulation.
    • Causes of Thrombocytosis

    • Primary

    • Myeloproliferative neoplasms - essential thrombocythaemia, polycythaemia vera, chronic myeloid leukaemia, myelofibrosis
    • Increased Production

    • Infection
    • Inflammation - autoimmune disease, major surgery, trauma, fracture, burns, pancreatitis, infarction
    • Malignancy
    • Drugs - adrenaline, corticosteroids, vinca alkaloids, thrombopoietin
    • Acute haemorrhage
    • Iron deficiency
    • Platelet Shift

    • Hyposplenism - splenectomy, liver cirrhosis, coeliac disease, sickle cell disease, SLE

Thrombocytopaenia

  • Reduced circulating platelets.
    • Causes of Thrombocytopaenia

    • Reduced Production

    • Congenital thrombocytopaenia - e.g. May-Hegglin, Bernard-Soulier
    • Bone marrow failure - aplastic anaemia, paroxysmal nocturnal haemoglobinuria
    • Bone marrow suppression - cytotoxic chemotherapy, radiotherapy, alcohol abuse
    • Bone marrow infiltration - leukaemia, multiple myeloma, lymphoma, metastasis, myelofibrosis
    • Myelodysplasia
    • B12 / folate deficiency
    • Increased Destruction

    • Autoimmune thrombocytopaenia - immune thrombocytopaenic purpura (ITP), SLE, antiphospholipid syndrome, rheumatoid arthritis
    • Alloimmune thrombocytopaenia - transfusion reaction
    • Drug-induced immune thrombocytopaenia - heparin-induced thrombocytopaenia (HIT), quinine, bactrim, vancomycin, rifampin, paracetamol, NSAIDs, glycoprotein IIb/IIIa inhibitors
    • Infection - HIV, hepatitis C, EBV, CMV, H pylori, sepsis
    • Thrombotic microangiopathies - thrombotic thrombocytopaenic purpura (TTP), haemolytic-uraemic syndrome (HUS), disseminated intravascular coagulation (DIC), HELLP syndrome
    • Gestation thrombocytopaenia 
    • Splenic Sequestration

    • Hypersplenism
    • Factitious

    • Platelet clumping
    • Haemodilution (e.g. massive transfusion)
 
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