Anemia, Megaloblastic

Question 1

Most megaloblastic anaemias result from a lack of either ______________ or _____________, and it is essential to establish in every case which deficiency is present and the underlying cause

Answer 1

vitamin B12

folate

Question 2

One cause of megaloblastic anaemia in the UK is _________________ in which lack of gastric intrinsic factor resulting from an autoimmune gastritis causes malabsorption of vitamin B12

Answer 2

pernicious anaemia

Question 3

Vitamin B12 is also needed in the treatment of megaloblastosis caused by prolonged ___________________, which inactivates the vitamin, and in the rare syndrome of congenital ___________________ deficiency.

Answer 3

nitrous oxide anaesthesia

transcobalamin II

Question 4

Vitamin B12 should be given prophylactically after _______________ or _______________ (surgeries)

Answer 4

total gastrectomy

total ileal resection (or after partial gastrectomy if a vitamin B12 absorption test shows vitamin B12 malabsorption)

Question 5

Apart from dietary deficiency, all other causes of vitamin B12 deficiency are attributable to _______________

Answer 5

malabsorption

Question 6

What is the preferred form of vit B12 for therapy?

Answer 6

Hydroxocobalamin; it is retained in the body longer than cyanocobalamin and thus for maintenance therapy can be given at intervals of up to 3 months

Question 7

Hydroxocobalamin is retained in the body longer than cyanocobalamin and thus maintenance therapy can be given at intervals of up to __________ months

Answer 7

3

• Treatment is generally initiated with frequent administration of intramuscular injections to replenish the depleted body stores

Question 8

Vit B12 treatment is generally initiated with frequent administration of ________________ to replenish the depleted body stores; Thereafter, maintenance treatment, which is usually for ____________, can be instituted

Answer 8

intramuscular injections

life

Question 9

Folic acid has few indications for long-term therapy since most causes of folate deficiency are ______________ or _______________

Answer 9

self-limiting (eg medication, pregnancy)

will yield to a short course of treatment

Question 10

_______________ should not be used in undiagnosed megaloblastic anaemia unless vitamin B12 is administered concurrently otherwise neuropathy may be precipitated

Answer 10

Folic acid

Question 11

Folic acid should not be used in undiagnosed megaloblastic anaemia unless vitamin B12 is administered concurrently otherwise _________________ may be precipitated

Answer 11

neuropathy

Question 12

Folic acid should not be used in undiagnosed megaloblastic anaemia unless _______________ is administered concurrently otherwise neuropathy may be precipitated

Answer 12

vitamin B12

Question 13

In folate-deficient megaloblastic anaemia (e.g. because of poor nutrition, pregnancy, or antiepileptic drugs), daily folic acid supplementation for _____________ brings about haematological remission and replenishes body stores

Answer 13

4 months

Question 14

For prophylaxis in chronic haemolytic states, malabsorption, or in renal dialysis, folic acid is given _________ or sometimes __________, depending on the diet and the rate of haemolysis

Answer 14

daily

weekly

Question 15

For prophylaxis in _____________, ____________, or in ____________, folic acid is given daily or sometimes weekly, depending on the diet and the rate of haemolysis

Answer 15

chronic haemolytic states

malabsorption

renal dialysis

Question 16

Folic acid is also used for the prevention of ___________-induced side-effects in severe Crohn’s disease, rheumatic disease, and severe psoriasis

Answer 16

methotrexate

Question 17

Folinic acid is also effective in the treatment of folate deficient megaloblastic anaemia but it is generally used in association with ________________; it is given as calcium folinate

Answer 17

cytotoxic drugs

Question 18

Folinic acid is also effective in the treatment of folate deficient megaloblastic anaemia but it is generally used in association with cytotoxic drugs; it is given as ________________

Answer 18

calcium folinate

Question 19

In what clinical contexts should multiple ingredient vitamin preparations containing Vit B12 or folate be given?

Answer 19

None; There is no justification for prescribing multiple ingredient vitamin preparations containing vitamin B12 or folic acid.

(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 [unlicensed] may be effective)

Question 20

What is the difference between folic acid and folinic acid?

Answer 20

Folic acid is synthetic

Folinic acid is found naturally in foods

Question 21

In addition to being used in the prevention of macrocytic anemia and the treatment of pernicious anemia, what are the other indications of hydroxocobalamin? (3)

Answer 21

1. Tobacco amblyopia (toxic amblyopia caused by tobacco containing cyanide)
2. Leber’s optic atrophy (inherited vision loss)
3. Cyanide poisoning

Question 22

How is Vit B12 administered?

Answer 22

IM or IV (in the case of cyanide poisoning)

Question 23

What are the side effects of hydroxocobalamin administration? (6)

Answer 23

1. Diarrhea, nausea
2. Dizziness
3. Headache
4. Hot flushes
5. Skin reactions
6. Urine discoloration

Question 24

What are the side effects of IV hydroxocobalamin? (13)

Answer 24

1. Angioedema
2. Dysphagia
3. Extrasystole
4. GI discomfort
5. Memory loss
6. Mucosal discoloration (red)
7. Peripheral edema
8. Pleural effusion
9. Pustular rash
10. Red discoloration of plasma
11. Restlessness
12. Swelling
13. Throat complaints

Question 25

What effect does IV hydroxocobalamin have on lab tests?

Answer 25

Deep red color of hydroxocobalamin may interfere with labs