Macrocytic Anaemias (haematology) Flashcards
What are the causes of macrocytosis except for vit b12 and folate deficiency? (6)
-Alcohol, smoking, liver disease, myeloma, drugs, reticulocytosis, aplastic anaemia.
Vit B12 and folate are essential for the synthesis of:
-DNA
Another name for vitamin B12
Cobalamin
Which protein transports cobalamin?
Transcobalamin
Causes of cobalamin deficiency (2)
Nutritional (vegans)
Malabsorption, can be due to gastric (pernicious anaemia) or intestinal causes.
How does pernicious anaemia cause vit b12 deficiency?
-It causes autoimmune gastritis, which leads to gastric atrophy, this causes reduced levels of acid and IF (binds with vit b12 to be absorbed) but elevated levels of gastrin.
What are the causes of folate deficiency?
-Nutritional
-Malabsorption
-Increased folate utilisation
-Increased loss or folate through urine
-Drugs
-Mixed
Pathogenesis of folate deficiency (4)
-Impaired DNA synthesis.
-Ineffective erythropoiesis, granulopoiesis and theombopoiesis.
-Exaggerated apoptosis of late precursors
-Haemolysis which reduced the red cell life span by 30-50%
What are the clinical features of folate deficiency (4)
-Glossitis
-Purpura
-Risk for neural tube defects and cardiovascular diseases.
-Reversible melanin pigmentation.
What are the laboratory features of folate deficiency? (5)
-Hypersegmented neutrophils.
-Low reticulocyte count.
-Leukocyte and platelets count may be reduced.
-Hypercellular bone marrow.
-Raised unconjugated bilirubin.
What is important to note with regards to the treatment of vit b12 and folate deficiency?
Do not give folic acid alone unless if vitamin b12 is excluded in the diagnosis because it can aggravate neuropathy.
Treatment for:
1. Vit B12 deficiency
2. Folate deficiency
- Hydroxocobalamin
- Folic acid
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