Macrocytic anaemia Flashcards
What is macrocytic anaemia?
- Anaemia = low Hb
* Macrocytic mean large cells, they have a high MCV
How can macrocytic anaemia be further sub divided?
*Megaloblastic and Normoblastic (refers to the appearance of bone marrow)
What are all the causes of macrocytic anaemia?
- Vit B12 deficiency
- Folate deficiency
- Alcohol
- Liver disease
- hypothyroidism
- Drug therapy e.g. azathioprine
What are the causes of megaloblastic macrocytic anaemia?
- Vit B12 deficiency
* Folate deficiency
How does VitB12 and folate deficiency result in megaloblastic macrocytic anaemia?
*Both lead to a block in DNA synthesis
What are the causes of Vit B12 deficiency?
*Vegans
*Impaired absorption
>Stomach: pernicious anemia, gastrectomy
>Small bowel: illeal disease/resection
What is pernicious anaemia?
Autoimmune disorder in which there is atrophic gastritis with loss of parietal cells in the gastric mucosa with consequent failure or intrinsic factor production and vit B12 malabsorption
What is the treatment of pernicious anaemia?
- 3 monthly vit B12 injections
* treat Vit b12 deficiency first then folic acid supplementation
What is the management of Vit B12 deficiency in general?
- 1mg IM hydroxocobalamin(vitB12) 3 times each week for 2 weeks, then once every 3 months
- treat Vit b12 deficiency first then folic acid supplementation
What are the causes of folate deficiency?
*Poor intake:
*Antifolate drugs:
>phenytoin
>methotrexate
>Trimethoprime
*Physiological excess utilization
>Pregnancy
>lactation
>prematurity
- Pathological excess utilization
- Malabsorption
What is the treatment of folate deficiency?
- 5mg folic acid daily
- treatment for 4months to replace body stores
- Prophylactic in pregnant women
What is MCV often used to monitor?
*Alcohol excess
