Platelet disorders

Platelets, derived from megakaryocytes, are involved in the formation of clot

Thrombocytopenia

• Low platelet count
• Low production in bone marrow
• High destruction in circulation
• Causes
• Reduced production
• Leukaemia
• Aplastic anaemia
• Megaloblastic anaemia
• Myeloma
• Immune destruction
• Autoimmune idiopathic thrombocytopenic purpura
• SLE
• Drugs
• Co-trimoxazole
• Coagulation
• DIC
• Haemolytic uraemic syndrome
• Infections
• Viral infection
• Other
• Hypersplenism

Autoimmune thrombocytopenic purpura

• Follows viral infection in children (acute)
• Idiopathic in adult women (chronic)
• 60% have anti-platelet antibodies
• Purpuric rash
• Epistaxis and menorrhagia
• Treat with steroids/splenectomy

Thrombocytosis

• High platelet count
• Haemorrhage
• Inflammation (any site)
• Essential thrombocythaemia