MACROCYTIC ANAEMIA Flashcards Preview

HAEMATOLOGY > MACROCYTIC ANAEMIA > Flashcards

Flashcards in MACROCYTIC ANAEMIA Deck (29):
1

What is the normal range for mean cell volume?

80-95 fl

2

What type of macrocytic anaemia does folate or B12 deficiency cause?

Megaloblastic anaemia (right shift)

3

What processes are affected by folate or B12 deficiency?

DNA synthesis

4

What is the daily requirement of vitamin B12?

1 microgram

5

Where is vitamin B12 absorbed?

Ileum

6

What must be present for vitamin B12 to be absorbed?

Intrinsic factor

7

Where is intrinsic factor excreted?

Parietal cells of the stomach.

8

What is the most common cause of vitamin B12 deficiency in the UK?

Pernicious anaemia

9

What is the underlying mechanism of pernicious anaemia?

Autoimmune gastritis where autoantibodies attack the parietal cells leading to a reduction in intrinsic factor.

10

Is pernicious anaemia more common in males or females?

Females

11

What is the peak age of onset for pernicious anaemia?

60

12

What diseases are associated with pernicious anaemia?

Vitiligo - patchy whiteness of the skin
Myxoedema
Hashimoto's disease
Addison's disease
Hypoparathyroidism

13

What is the daily requirement of folate?

100-200 micrograms

14

Where is folate absorbed in the intestine?

Upper small intestine

15

How long do body stores of folate usually last for?

4 months

16

What disease is especially associated with folate deficiency?

Coeliac disease

17

What are the clinical features of megaloblastic anaemia caused by a vitaman B12 or folate deficiency?

Pallor
Jaundice
Gradual onset
May present with signs of congestive heart failure

18

What does the blood film of someone with anaemia related to vitamin B12 or folate deficiency look like?

Oval macrocytes
Hypersegmented neutrophil neuclei
Low white cell or platelet count

19

What are the characteristics bone marrow features of megaloblastic anaemia?

Megaloblastic erythroblasts
Giant metamyelocytes

20

Other than low Hb, what might a blood test of someone with megaloblastic anaemia show?

Raised unconjugated bilirubin
Raised serum lactic dehydrogenase
Low B12
Low folate
Raised serum homocysteine
Parietal cell antibodies
Intrinsic factor antibodies

21

Why is jaundice associated with megaloblastic anaemia?

Increased destruction of the red cell precursors in the marrow

22

Other than anaemia, what other effects are there from a vitamin B12 or folate deficiency?

Neuropathy
Neural tube defects
Gonadal dysfunction
Epithelial changes - such as glossitis
Cardiovascular disease

23

What is the most common cause of raised MCV of red blood cells (macrocytosis) in the UK?

Alcohol - even quite small amounts and not necessarily associated with liver disease

24

What are the causes of raised MCV of red blood cells?

Megaloblastic anaemia (B12 and folate)
Alcohol
Pregnancy and neonatal period
Myelodysplasia
Aplastic anaemia
Changes in plasma protein (eg paraproteins associated with myeloma)
Drugs - hydroxyurea and azathioprine
Benign familial macrocytosis
Hypothyroidism

25

Other than blood tests, what investigations would you do with someone who presented with megaloblastic anaemia?

Bone marrow examination
Radioactive vitamin B12 absorption study - with and without intrinsic factor
Endoscopy - to confirm atrophic gastritis or exclude gastric carcinoma

26

What are the causes of megaloblastic anaemia?

Diet
Pernicious anaemia
Congenital intrinsic factor deficiency
Gastrectomy
Atrophic gastritis
Stagnant loop
Congenital selective malabsorption
Ileal resection
Crohn's
Coeliac disease
Jejunal resection
Drugs - anticonvulsants, sulphasalazine

27

What is the medical treatment of vitamin B12 deficiency?

Initial treatment is injections of hydroxycobalamin 1 mg every 3-4 days, followed by 4 injections a year for life.

28

What is the medical treatment of folate deficiency?

Folic acid 5 mg daily for 4 months
Those with severe haemolytic anaemia should continue to have this dose once a week.

29

What must you do before starting someone on treatment for folate deficiency?

Check vitmamin B12 levels as treatment may correct anaemia but allow neurological disease to develop.