macrocytic anaemia

Question 1

define macrocytic anaemia

Answer 1

Anaemia characterised by larger than normal red blood cells.
Usually deficient in B12 or folate.

Question 2

pathophysiology of macrocytic anaemia

Answer 2

RBCs are too big and are either
megaloblastic or non-megaloblastic.

Question 3

what are megaloblasts

Answer 3

large nucleated red blood cells
with hyper-segmented neutrophils with 6 or more lobes

Question 4

what are megaloblasts associated with

Answer 4

slow/impaired DNA synthesis.

Question 5

what are the 2 main megaloblastic macrocytic anaemias

Answer 5

• B12 deficiency (years to develop)
• Folate deficiency (months to develop).

Question 6

what is non megaloblastic anaemia a result of

Answer 6

is usually a result of various factors such as
- alcohol
- liver diseases
- hypothyroidism

Question 7

what is folate

Answer 7

the natural form of vitamin B9

Question 8

is folate stored

Answer 8

no
which is why 0.1-0.2mg is needed
daily.

Question 9

6 causes of folate deficiency

Answer 9

1. malnutrition
2. malabsorption
3. pregnancy
4. alcohol
5. bacterial overgrowth
6. drugs - (trimethoprim or methotrexate).

Question 10

how is vitamin b12 absorbed

Answer 10

1. Vitamin B12 binds to
   transcobalamin 1 in saliva
2. and then binds to intrinsic factor in
   the duodenum.
3. Intrinsic factor is secreted by
   parietal cells, forms a B12-IF
   complex
4. and is absorbed in the terminal ileum

Question 11

what is disrupted in vitamin b12 deficiency

Answer 11

the absorption of vitamin b12

Question 12

2 main causes of vitamin b12 deficincy

Answer 12

1. not having enough b12
2. poor absorption

Question 13

what factors contribute to not having enough vitamin b12

Answer 13

veganism and malnutrition

Question 14

what factors contribute to having poor absorption of vitamin b12

Answer 14

1. gastrectomy
2. bowel pathology
3. oral contraceptives
4. nitrous oxide use

Question 15

what is pernicious anaemia

Answer 15

Antibodies target either parietal
cells or intrinsic factor,
resulting in decreased B12-IF
complexes.

Question 16

signs and symptoms of b12 deficiency

Answer 16

*Angular stomatitis
* Glossitis
* yellow skin
* Fatigue
* weakness

Question 17

neurological symptoms associated with b12 deficincy

Answer 17

• Paraesthesia
• Demyelination
• Muscle weakness
• Altered mental state

Question 18

signs and symptoms of folate deficiency

Answer 18

• Angular stomatitis
• Fatigue
• Weakness
• shortness of breath

Question 19

treatment for b12 deficiency

Answer 19

Dietary Advice and B12 supplements.

Question 20

treatment for folate deficiency

Answer 20

Dietary Advice.
Check B12 and folate levels.
Then give supplements as required. (Folate can decrease B12)

Question 21

treatment for non-megaloblastic anaemia

Answer 21

treat underlying cause

Question 22

main investigation for macrocytic anaemia (general)

Answer 22

FBC + Blood film = Macrocytic, high MCV

Question 23

what does investigation for b12 deficiency show

Answer 23

• Megaloblasts present
• low serum B12
• Anti parietal and anti IF antibodies

Question 24

what does investigation for folate deficiency show

Answer 24

• Megaloblasts
• low serum folate
• could have low B12