Description of megaloblastic anaemia Flashcards
1
Q
Macrocytic anaemias are anaemia with?
A
Large RBC’s, MCV > 100 fL (Large RBCs), Hb low (fewer RBC)
2
Q
Causes of macrocytic anaemia?
A
- Alcohol and liver disease
- Hypothyroidism
- Reticulocytotic
- Drugs
- Bone marrow disorders
3
Q
Definition of “megaloblastic”
A
Larger MCV > 110 fL is caused by impaired DNA synthesis
4
Q
Common causes of megaloblastic anaemia?
A
- Deficiency of vitamin B12 (cobalamin) &/or folate.
- Abnormalities of vitamin B12
- Insufficient folate metabolism: e.g. transcobalamin deficiency
- Nitrous oxide exposure (inactivates B12)
- Anti-folate drugs (e.g. methotrexate, trimethoprim)
5
Q
Other defects of DNA synthesis causing megaloblastic anaemia
A
- Congenital enzyme deficiency
- Chemotherapy drugs (zidovudine, azathioprine, hydroxyurea, cytarabine, 6-mercaptopurine, cladribine)
6
Q
Non-megaloblastic anaemia conditions
A
MCV < 1110 fL, normal DNA synthesis.
7
Q
Causes of non-megaloblastic anaemia
A
It can be due to increased reticulocytes (MCV 103-126 fL) due to bleeding or haemolysing.
There can also be a change in membrane structure or water content of RBC.
