Vitamin B12 and/or folate deficiency

Question 1

What is the function of vitamin B12 and folate in the body?

Answer 1

they are required for synthesis of purine and pyrimidine bases

Question 2

Describe the relationship between B12 and folate:

Answer 2

vitamin B12 is essential for cell folate generation

Question 3

Where is B12 absorbed?

Answer 3

Terminal ileum

Question 4

What molecule aids the absorption of B12 in the terminal ileum?

Answer 4

intrinsic factor

Question 5

What cells produce intrinsic factor?

Answer 5

gastric parietal cells

Question 6

Where is folate absorbed?

Answer 6

jejunum

Question 7

What are the two main causes of folate deficiency?

Answer 7

1. Poor diet
2. Malabsorption

Question 8

Give 3 instances where folate consumption is increased:

Answer 8

1) pregnancy
2) haemolysis
3) inflammatory disorders

Question 9

Give 5 causes of B12 deficiency:

Answer 9

1) pernicious anaemia
2) insufficient dietary intake
3) medications
4) gastrectomy (less intrinsic factor produced)
5) terminal ileum resection (cannot absorb B12)

Question 10

What type of anaemia does B12 deficiency cause?

Answer 10

Macrocytic (specifically megaloblastic)

Question 11

What is pernicious anaemia?

Answer 11

an autoimmune condition involving antibodies against parietal cells or intrinsic factor which results in malabsorption of B12

Question 12

Give 5 neurological symptoms caused by B12 deficiency?

Answer 12

1) peripheral neuropathy with numbness and paraesthesia
2) loss of vibration sense
3) loss of proprioception
4) visual changes
5) mood and cognitive changes

Question 13

What simple blood test should be conducted for any patient with peripheral neuropathy?

Answer 13

B12 serum levels

Question 14

Give 6 non-neurological manifestations of B12 deficiency:

Answer 14

1. Megaloblastic anaemia
2. Mild jaundice
3. Anorexia
4. Glossitis
5. Angular stomatitis
6. Pancytopenia (Pancytopenia is a condition in which a person’s body has too few red blood cells, white blood cells, and platelets)

Question 15

Why is mild jaundice seen in B12 deficiency?

Answer 15

haemolysis of megaloblastic red blood cells increases serum bilirubin

Question 16

Give 5 blood tests used to diagnose vitamin B12 deficiency:

Answer 16

1) FBC
2) blood film (increased MCV and decreased reticulocytes)
3) B12 and folate serum levels
4) antibodies against IF or parietal cells
5) bilirubin and lactate dehydrogenase levels (indicates haemolysis of megaloblastic RBCs)

Question 17

What injection is given to those with B12 deficiency?

Answer 17

hydroxycobalamin

Question 18

How often is IM hydroxycobalamin initially given to patients with B12 deficiency and neurological symptoms?

Answer 18

every other day

Question 19

How often is IM hydroxycobalamin initially given to patients with B12 deficiency and no neurological symptoms?

Answer 19

3 times weekly for 2 weeks

Question 20

How often is IM hydroxycobalamin given to maintain B12 levels in those with pernicious anaemia?

Answer 20

2-3 monthly injections

Question 21

What are the two treatments used to maintain B12 levels in those with dietary-associated B12 deficiency?

Answer 21

1) oral cyanocobalamin
2) twice years IM hydroxycobalamin

Question 22

Why should B12 deficiency be treated before folate deficiency in patients suffering with both?

Answer 22

giving folic acid in the presence of a B12 deficiency can lead to subacute combined degeneration of the cord

Question 23

What is subacute combined degeneration of the cord (SACDC)?

Answer 23

demyelination of the spinal cord, causing severe neurological issues such as distal weakness and dementia

Question 24

A deficiency of which carrier protein leads to B12 not being able to be functionally used in the body causing megaloblastic anaemia?

Answer 24

transcobalamin (a B12 carrier protein required for its functional use)