Thrombocytopenia ( Low platelet count )

Approach to Thrombocytopenia or low platelet count on A4Medicine.co.uk

definitions -Count below the 2.5 th lower percentile of the normal platelet count distribution.Traditional cut-off is < 150 x 109 National Cancer Institute - severity criteria Grade 1 From 75000 to 150 , 000 Grade 2 From 50,000 to < 75,000 Grade 3 From 25,000 to < 50, 000 Grade 4 Below 25,000

Causes- Decreased production Marrow failure -○ Aplastic anaemia Marrow infiltration-○ leukaemias○ Myelodysplasia○ myeloma○ myelofibrosis○ lymphoma○ metastatic carcinoma Marrow suppression○ cytotoxic drugs○ radiotherapy○ drugs HIV Vit D Deficiency Hereditary causes eg○ hereditary thrombocytopenia

increased destruction Immune-ITP HIT ( heparin induced ) Drug induced antibodies Infection eg○ HIV○ other viruses○ Malaria Post transfusion Connective tissue disease Non-Immune-DIC Sepsis Cardiac valves TTP / HUShaemolytic uraemic syndrome Cardiopulmonary bypass Kassabach Merrit Syndrome

Pseudothrombocytopenia-Laboratory artifact caused by platelet clumping due to naturally occurring antibodies directed against normally hidden epitopes of platelet surface antigens-Essential to r/o before considering other causes

history-Bruising or bleeding - check particularly about epistaxis , haematuria and menorrhagia or previous episode of heavy bleeding following eg childbirth , dental extraction Ask about recent viral infection Pregnancy- risk of TTP , gestational thrombocytopenia , HELLP Liver disease -Alcohol history , chronic...