Macrocytosis Asnd Macrocytic Anaemia Flashcards
How is macrocytosis defined?
MCV > 100
What is a megaloblast?
An abnormally large nucleated red cell precursor with an immature nucleus.
Megaloblastic anaemias are characterised by what?
By predominant defects in DNA synthesis and nuclear maturation with relative preservation of RNA and Hb synthesis.
Name a few common causes of megaloblastic anaemia and why they cause this type of anaemia?
- B12 deficiency
- Folate deficiency
B12 and folate are essential co-factors for nuclear maturation.
Where is B12 absorbed from?
The terminal ileum
Where is folate absorbed from?
The duodenum and jejunum.
Body stores of Folate and B12
Folate only 4months, B12 2-4 years.
Clinical features of B12 and folate deficiency? Features of only B12 deficiency?
Common to both:
- Symptoms/signs of anaemia.
- Weight loss, diarrhoea, infertility,
- Sore tongue, jaundice.
- Devlopmental proble,s
Vitamin B12 only: Neurological findings, neuropathy, dementia.
Rule of management: FOLATE should NOT be given alone, failing to provide B12 alongside can precipitate subacute combined degeneration of the spinal cord.
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What is pernicious anaemia?
Autoimmune atrophic gastritis in which there is a reduction in the production of Intrinsic factor and HCl. Associated with other autoimmune condition.s
What does the blood film show in peencisious anaemia?
Macrovalocytes and hypersegmented neutrophils. (3-5 nuclear segments)
Macrocytic anaemia.
Check for which autoantibodies in megaloblastic anaemia?
Check for autoantibodies Anti GPC and Anti IF
Anti-IF = specific, not sensitive.
Anti-GPC= sensitive, not specific.
Causes of non-megaloblastic macrocytosis?
Alcohol
Liver disease
Hypothyroidism.
What are the causes of spurious macrocytosis?
Reticulocytosis
Cold agglutinins
Management of folate deficiency?
5mg for 4 months. But remember do not give folate alone.
Also give IM B12 (cobalamin)
