Anaemia Flashcards
Appearance of RBC in iron deficiency anaemia
Hypochromic, microcytic
Appearance of RBC in folate or B12 deficiency
Macrocytic
Features of megaloblastic anaemia
Common causes: B12 and folate deficiency Morphological changes in bone marrow Inhibition of DNA synthesis in bone marrow
Outline B12 absorption
B12 absoprtion requires binding by intrinsic factors (secreted by the parietal cells of the stomach).
B12 is bound by salivary R protein.
This is displaced by trypsin (activated by enterokinase), allowing the binding of intrinsic factor.
Causes of B12 deficiency
Diet: Sources include red meat and dairy Malabsorption: - Pernicious anaemia (autoimmune attach on stomach cells, destroys intrinsic factor secreting parietal cells. B12 is required for RBC synthesis. Reduced levels lead to reduced RBC synthesis and anaemia)
Clinical features of B12 deficiency
Lemon yellow skin, glossitis, hepatosplenomegaly, bruising and bleeding, - DO NOT TRANSFUSE PATIENTS (can cause spinal cord degeneration)
Importance of folate
Folate is required for the synthesis of DNA
Causes of folate deficiency
Diet: Sources include green leafy vegetables Pregnancy and lactation Haematological disease
Mechanism of iron absorption
Transported across the membrane by DMT1. Iron is either used or stored as ferritin.
Effect of hepcidin on iron absorption
Hepcidin is an acute phase protein released from the liver during inflammation. It acts through binding the iron transport channels, reducing the uptake of iron.
Causes of iron deficiency anaemia
Diet Malabsorption: Coeliac disease, H. pylori infection GI blood loss: Ulcers (aspirin use), adenocarcinoma Non-GI blood loss: Menstruation, blood donation
Treatment of IDA
Iron supplement
Haemolytic anaemia: Mechanism, cell appearance
Mechanism: Caused by autoimmune destruction of RBCs. Autoantibodies attach to the surface of the RBCs, leading to RBC destruction Cell appearance: Normocytic
