Macrocytic Anaemia Flashcards
What is macrocytic anaemia?
Reduced RBCs with larger volume than expected.
What are the 2 sub-types of macrocytosis?
Megaloblastic
Non-megaloblastic
What are RBC precursors that contain a nucleus?
Erythroblasts
Normoblasts
What is a megaloblast?
An abnormally large nucleated RBC precursor that contains an immature nucleus.
What is the cause of megaloblastic anaemia?
Defects in DNA synthesis and nuclear maturation.
What occurs in megaloblast maturation?
Cell division with an increased rate of apoptosis.
Triggering of Hb threshold occurs, pushing out the cell nucleus, creating a macrocyte.
What are the 2 main causes of macrocytic anaemia?
B12 deficiency
Folate deficiency
What chemicals are important in preventing megaloblastic anaemia?
Folate and vitamin B12.
What binds to vitamin B12 in the stomach and carries it to the duodenum?
Rapid binding proteins
After the dudoenum, what carries B!”?
Intrinsic factor
Where is vitamin B12 absorbed?
The ileum
What is pernicious anaemia?
Autoimmune destruction of gastric parietal cells - results in an inability to secrete intrinsic factor.
What is the result of pernicious anaemia?
B12 deficiency.
What conditions are linked to pernicious anaemia?
Hypothyroidism
Vitiligo
Addison’s disease
In which food is vitamin B12 found?
Animal food
In which food is folate found?
Plant food
What can cause folate deficiency?
Inadequate dietary intake
Malabsorption
Excess utilisation
Where is folate absorbed?
The jejunum
What sign is specific to B12 deficiency?
Neurological issues
May lead to subacute spinal cord compression.
What are features seen in both folate and vitamin B12 deficiencies?
Signs/Symptoms of anaemia Weight loss Diarrhoea Infertility Sore tongue Developmental issues
What are the symptoms common to all anaemias?
Fatigue
SOB
Impaired concentration
What are causes of non-megaloblastic macrocytic anaemia?
Alcohol
Liver disease
Hypothyroidism
Bone marrow failure
What are causes of false macrocytosis?
Reticulocytosis
Cold-agglutins
What is the cause of cold-agglutins?
Abnormal protein
Clumping of RBCs due to storage at colder temperature than body temperature.
How is pernicious anaemia screened for?
Check for presence of autoantibodies.
Can macrocytic anaemia cause jaundice?
Yes, as macrocytes cannot pass through openings as easily.
Can B12/Folate deficiency cause pancytopenia?
Yes, as absence of these increases apoptosis of all cell type precursors.
