Anaemia

• Anaemia definition =

  Reduced total red cell mass

  Hb concentration + Haematocrit
• Pathophysiological classification of anaemia =

  Decreased production = low reticulocyte count

  Hypoproliferative - reduced erythropoiesis

  maturation abnormality

  Increased loss or destruction of red cells = high reticulocyte count

  Bleeding

  Haemolysis
• MCV low (microcytic) = problems with Hb

  MCV high (macrocytic) = problems with maturation
• Causes of microcytic anaemias =

  Haem deficiency

  • lack of iron for erythropoiesis - iron deficiency
  • lead poisoning

  Globin deficiency

  • thalassaemia
• Causes of macrocytic anaemias =

  Nuclear maturation defects - failure of cell division

  • B12/folate
  • myelodysplasia
  • drugs - chemo

  Agglutination (RBCs stuck together by antibodies)

  Reticulocytosis
• Megaloblastic anaemias are characterised by lack of red blood cells due to defects in DNA synthesis and nuclear maturation. RNA and haemoglobin synthesis are preserved.

  Proerythroblasts expand

  Maturing erythroblasts - division reduced + apoptosis increases
• Macrosytosis without significant anaemia =

  Hypothyroidism

  Alcohol

  Liver disease
• Normocytic anaemia =

  Renal impairment

  Chronic disease

  Marrow infiltration

  Marrow failure
• Megaloblast = precursor cell is bigger with an immature nucleus.

  Hb level becomes optimal = nucleus is extruded - leaving bigger cell.

  Fewer macrocytes = anaemia