megaloblastic anaemia Flashcards
Most megaloblastic anaemias result from lack of either B12 or folate. Need to establish which deficiency is present in each case and the underlying cause. But what would you do in emergencies?
Delay could be dangerous
Sometimes necessary to administer both B12 and folate after bone marrow test whilst waiting for plasma assay results
This is one cause of megaloblastic anaemia in the UK, in which lack of gastric intrinsic factor resulting from an autoimmune gastritis causes malabsorption of vit B12
pernicious anaemia
One cause of megaloblastic anaemia in the UK is pernicious anaemia - how does this occur?
lack of gastric intrinsic factor resulting from an autoimmune gastritis causes malabsorption of vitamin B12.
in pernicious anaemia does the pt have B12 or folate deficiency
B12
what is needed in the treatment of the rare syndrome of congenital transcobalamin II deficiency? folate or B12?
B12
What is needed in the treatment of megaloblastosis caused by prolonged nitrous oxide anaesthesia?
B12
It inactivates the vitamin
What effect can prolonged nitrous oxide treatment anaesthesia have?
It inactivates vitamin b12
thus B12 will be needed in the treatment of megaloblastosis caused by prolonged NO anaesthesia
What needs to be given prophylactically after total astrectomy or total ileal resection
B12
True or false. Vitamin B12 should be given after partial gastrectomy.
False
Only give if vit B12 absorption test shows malabsorption.
It should be given prophylactically for TOTAL gastrectomy or total ileal resection
Apart from diet deficiency, all other caused of B12 deficiency are due to ..
malabsorption
Discuss the use of oral vit B12 - low dose, instrinsic factor complexes, large doses
There is little place for the use of low-dose vitamin B12 orally and none for vitamin B12 intrinsic factor complexes given by mouth. Vitamin B12 in larger oral doses may be effective.
T or F - hydroxycobalamin retained in body longer than cyanocobalamin
True
Hydroxocobalamin is retained in the body longer than cyanocobalamin and thus for maintenance therapy can be given at intervals of up to how many months?
3 months
What does vit B12 treatment usually consist of
Treatment is generally initiated with frequent administration of intramuscular injections to replenish the depleted body stores. (hydoxycobalamin)
Thereafter, maintenance treatment, which is usually for life, can be instituted.
True or false - maintenance treatment of vit B12 is usually for life
true
Do larger doses than those recommended provide additional benefit in vit B12 neuropathy?
There is no evidence that doses larger than those recommended provide any additional benefit in vitamin B12 neuropathy.
Discuss the use of folic acid as long term therapy
Folic acid has few indications for long-term therapy since most causes of folate deficiency are self-limiting or will yield to a short course of treatment.
Can you use folic acid in undiagnosed megaloblastic anaemia?
No, unless vitamin B12 is administered concurrently otherwise neuropathy may be precipitated.
In folate-deficient megaloblastic anaemia (e.g. because of poor nutrition, pregnancy, or antiepileptic drugs), how would you treat it & for how long?
daily folic acid supplementation for 4 months brings about haematological remission and replenishes body stores.
Drug therapy of folic acid for prophylaxis in chronic haemolytic states, malabsorption, or in renal dialysis
folic acid is given daily or sometimes weekly, depending on the diet and the rate of haemolysis.
What is folinic acid used for (anaemia indication)?
What is it given as?
Is it given alongside anything?
effective in the treatment of folate deficient megaloblastic anaemia but it is generally used in association with cytotoxic drugs; it is given as calcium folinate.
what do most megaloblastic anaemias result from? (2)
either lack of B12 or folate
