What are the three big umbrella causes of anaemia?
1) Low RC production (BM infiltrates eg. Aplastic anemia, MDS; Fe/B12/folate def; chemoTx, drugs; hormone def EPO, thyroxine)
2) Increased RC destruction (haemolysis when RC destroyed in <100 days, inherited conditions eg. Hereditary spherocytosis, Thal major, Sickle cell disease; acquired eg. PTP-HUS, autoimm anaemia, malaria)
3) Blood loss (most common cause)