Condition- Macrocytic Anaemia Flashcards
What is macrocytic anaemia?
Anaemia associated with a high MCV (>100 in adults)
In general what causes macrocytic anaemia?
Macrocytic anaemia usually results from abnormal haemopoiesis so that the red cell precursors continue to synthesise haemoglobin and other cellular proteins but they fail to divide normally
Macrocytic anaemia can be divided into megaloblastic and non-megaloblastic anaemia. What are megaloblasts- state two key features?
Megaloblasts= delay in the maturation of the nucleus while the cytoplasm continues to mature and the cell continues to grow due to abnormalities in DNA synthesis
- Megaloblasts are larger than normal
- They show nucleo-cytoplasmic dissociation
- Immature open chromatin + normal pink haemoglobinised cytoplasm
Mnemonic to remeber differentials for macrocytic anaemia
Macrocytic anaemia: differential FAT RBC:
- Fetus (pregnancy)
- Alcohol
- Thyroid disease(ie hypothyroidism)
- Reticulocytosis
- B12 and folate deficiency
- Cirrhosis and chronic liver disease
List the causes of megaloblastic macrocytic anaemia
- B12 deficiency (vegans, PA, gastrectomy)
- Folate deficiency (alcoholics, pregnancy, coeliac)
- Drugs:
- Methotrexate
- Hydroxyurea
- Azothioprine
- Zidovudine
List the causes of non-megaloblastic macrocytic anaemia
FAT R(B)Cs in Macrocytic non-Megaloblastic Anaemia
- Foetus- Pregnancy
- Alcohol
- Thyroid problem- Hypothyroidism
- Reticulocytosis due to haemolysis
- Cirrhosis, liver disease – ROUND macrocytes
- Cytotoxic Drugs
- Myelodysplasia
- Multiple myeloma
- Aplastic anaemia
What is the most common cause of macrocytosis in the west?
B12 deficiency
What might a patient have in their hx that might suggest macrocytic anaemia?
- PMHx
- IBD
- Previous GI surgery- gastrectomy
- FHx
- autoimmune disease- PA
- SHx:
- alcohol
- pregnancy
- vegan diet
List some of the signs of pernicious anameia
- Mild jaundice
- Glossitis
- Angular stomatitis
- Weight loss
List some of the signs of B12 deficiency
- Peripheral neuropathy
- Ataxia
- Subacute combined degeneration of the spinal cord
- Optic atrophy
- Dementia
- Positive Babinski’s, absent ankle reflex, increase knee reflex
What derangement is commonly seen in LFTs and why?
High Bilirubin (due to ineffective erythropoiesis or haemolysis)
What blood tests are done to detect B12 and folate levels?
Serum cobalamin
Red cell folate
3 changes you’d see in the blood film of someone with megaloblastic anaemia?
- Macrocytic cells
- Nuclear-cytoplasmic dissociation
- Hypersegmented neutrophils
What test is done to diagnose pernicious anaemia?
Schilling Test
- Method of testing for pernicious anaemia
- B12 will only be absorbed when given with intrinsic factor
What is a potential complication of folate deficiency in during pregnancy
Neural tube defects in newborn e.g. spina bifida, anencephaly
