Macrocytic Anaemia

Question 1

What is a megaloblastic cell?

Answer 1

A cell in which nuclear maturation is delayed compared with the cytoplasm.

Question 2

What causes megaloblastic anaemia?

Answer 2

B12 and folate deficiency and cytotoxic drugs.

Question 3

What is seen on these result in megaloblastic anaemia?

Hb, MCV, reticulocyte count.

Answer 3

1. Hb low
2. MCV raised
3. Reticulocyte count low

Question 4

What are the causes of non-megaloblastic anaemia?

Answer 4

Alcohol excess, haemolysis, liver disease, hypothyroidism, pregnancy.

Question 5

Which foods contain folate?

Answer 5

Green leafy vegetables, nuts, yeast, liver.

Question 6

Where is folate absorbed?

Answer 6

Duodenum and proximal jejunum

Question 7

What are the drugs that interfere with folate metabolism and absorption?

Answer 7

Methotrexate, metformin, trimethoprim, sulfasalazine, HIV medication, sodium valproate, direct alcohol toxicity.

Question 8

What are the causes of folate deficiency due to increased demand?

Answer 8

1. Pregnancy/breastfeeding
2. Infancy and growth spurts
3. Haemolysis and rapid cell turnover
4. Disseminated cancer

Question 9

What are the causes of folate deficiency due to decreased intake?

Answer 9

1. Poor diet
2. Elderly
3. Chronic alcohol intake

Question 10

What are the causes of folate deficiency due to decreased absorption?

Answer 10

1. Medication
2. Coeliac
3. Jejunal resection

Question 11

What is the treatment for folate deficiency anaemia?

Answer 11

1. Assess for underlying cause and folic acid 5mg/day PO for 4 months
2. Improve diet with foods high in folate

Question 12

What foods are high in vitamin B12?

Answer 12

Fish, meat, dairy

Question 13

What are the causes of vitamin B12 deficiency?

Answer 13

1. Dietary (vegans)
2. Malabsorption (lack of intrinsic factor/post-gastrectomy)
3. Ileal resection, Crohn’s disease
4. Bacterial overgrowth

Question 14

What are the clinical features of B12 deficiency anaemia in these areas?

1. General
2. Brain
3. Neurology

Answer 14

1. Symptoms of anaemia, glossitis
2. Irritability, depression, psychosis, dementia
3. Neuropathy, myopathy, ataxia, gait abnormalities.

Question 15

What is the treatment for B12 deficiency anaemia?

Answer 15

1. Improve diet, increase foods containing vitamin B12.

2. Injections - 5x 1mg given over 2 weeks, then every 3 months maintenance.

Question 16

What is pernicious anaemia?

Answer 16

Autoimmune condition in which atrophic gastritis leads to a lack of intrinsic factor secretion from parietal cells in the stomach. Dietary B12 remains unbound and consequently cannot be absorbed by the terminal ileum.

Question 17

What is pernicious anaemia associated with?

Answer 17

1. Other autoimmune conditions - thyroid, vitiligo, Addison’s, hypoparathyroidism
2. Carcinoma of the stomach 3x more likely in pernicious anaemia - low threshold for OGD

Question 18

What is seen on these result in pernicious anaemia and what additional tests may you need?
Hb, MCV, WCC, platelets, B12.

Answer 18

1. Hb low, MCV high, WCC low, platelets low (severe), serum B12 low.
2. Parietal cell Abs +ve in 90%, intrinsic factor Abs specific for PA but low sensitivity.

Question 19

What is the treatment for pernicious anaemia?

Answer 19

1mg B12 IM alternate days for 2 weeks then every 3 months for life.