Macrocytic anaemia Flashcards
Two types of macrocytic anaemia
Megaloblastic
Non-megaloblastic
What is the underlying pathophysiology of megaloblastic macrocytic anaemia?
Defects in DNA synthesis and nuclear maturation
Causes of megaloblastic anaemia (2)
B12 deficiency
Folate deficiency
Why do b12 and folate deficiencies cause megaloblastic anaemia?
b12 and folate are essential co-factors for nuclear maturation
Protein which is essential for the absorption of vitamin B12
Intrinsic factor
Where is intrinsic factor produced from?
Gastric parietal cells
Where is the IF-B12 complex absorbed?
Terminal ileum
Condition where auto-antibodies against either intrinsic factor or gastric parietal cells
Pernicious anaemia
Why might gastrectomy (partial or otherwise) cause B12 deficiency? (2)
Failure to produce IF; failure to digest animal products adequately to release B12
Situations where increased folate utilisation/requirement may cause deficiency (4)
Haemolysis
Pregnancy
Malignancy
Exfoliating dermatitis
Drug class which may cause folate deficiency
Anti-convulsants
Malabsorptive causes of folate deficiency (2)
Crohns
Coeliac
Symptoms/signs of both B12 and folate deficiency (4)
Weight loss
Diarrhoea
Glossitis
Jaundice
Neurological problems caused by b12 deficiency (2)
Dorsal column abnormalities
Peripheral neuropathy
Treatment of megaloblastic anaemia
Treat the cause where possible
Vit B12 injections for life in pernicious anaemia
Folic acid tablets 5mg/day
