4: Macrocytosis and macrocytic anaemia Flashcards Preview

Haematology Week 1 2018/19 > 4: Macrocytosis and macrocytic anaemia > Flashcards

Flashcards in 4: Macrocytosis and macrocytic anaemia Deck (40)
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1

What is macrocytic anaemia?

Reduction in red blood cell number in which the red blood cells are larger than normal

2

In macrocytic anaemia, haemoglobin is (high / low) and MCV is (high / low).

Hb low

MCV high (> 100 fL)

3

What is macrocytosis?

Increase in red blood cell size

NOT the same as macrocytic anaemia (Hb and red cell count normal)

4

Normal ranges for MCV vary from hospital to hospital.

On a blood film, what can red blood cells be compared with to say whether or not they are macrocytic?

Nucleus of a lymphocyte

because they tend to be larger than an RBC should be

5

What values of MCV are

a) normal

b) indicative of macrocytosis?

a) 80 - 100 fL

b) > 100 fL

6

Where are red blood cell precursors found?

Bone marrow

7

Before reticulocytes, what are precursor red blood cells called?

Do they have a nucleus?

Erythroblast

Yes

8

What do precursors to red blood cells accumulate as they divide?

Hb

9

Red blood cell precursors get (bigger / smaller) as they divide.

smaller

10

Where are reticulocytes found?

Circulation

11

What do reticulocytes lose before becoming mature RBCs?

RNA

12

What is a megaloblast?

Big erythroblast (precursor RBC) with abnormal nucleus

13

What happens to

a) Hb synthesis

b) DNA synthesis and nuclear maturation

c) RNA synthesis

in a megaloblast?

a) Normal

b) Abnormal

c) Normal

i.e this is a problem with the DNA / nucleus, which remember causes a macrocytic anaemia

14

What does a megaloblast turn into when it differentiates?

Macrocyte

Due to nuclear problem, most of the cells have undergone apoptosis, so cell count is reduced (macrocytic anaemia)

15

What is the main causes of megaloblastic (a type of macrocytic) anaemia?

Vit B12 / Folic acid deficiency

16

Why do Vit B12 and folic acid deficiencies cause megaloblastic anaemia?

Both involved in DNA synthesis and nuclear maturation

17

What genetic process are Vit B12 and folic acid involved in?

Gene silencing

18

Which vitamin is carried to the distal ileum by intrinsic factor?

Vit B12

19

Which protein carries Vitamin B12 to the duodenum before it is bound to intrinsic factor?

R protein

20

In which foods is Vitamin B12 found?

Animal products

Red & white meat, fish, eggs, cow's milk

21

Who is prone to Vitamin B12 deficiency?

People who don't eat animal products

People on PPIs (inadequate stomach acid to liberate Vit B12 from food)

People at risk of malabsorption (overgrowth, surgical resection)

Alcoholics (indaequate nutrition)

22

Which stomach cells produce intrinsic factor?

Parietal cells

23

In which autoimmune disease are gastric parietal cells destroyed?

Pernicious anaemia

Causes Vit B12 deficiency

24

Who is prone to folate deficiency?

Alcoholics (inadequate nutrition)

25

What are the general symptoms of anaemia?

Pallor

Fatigue

Difficulty concentrating

Dizziness

Shortness of breath

26

What are specific symptoms of Vit B12 / folic acid deficiency?

GI problems - weight loss, diarrhoea, jaundice etc. - suggest a primary GI cause

Glossitis (sore tongue)

Delayed development

27

What irreversible neurological changes are caused by Vit B12 deficiency?

Delayed degeneration of dorsal columns (spinothalamic tract)

Dementia

NOT the same as the B1 encephalopathy

28

What are blood film findings specific to macrocytic anaemia caused by Vit B12 / folate deficiency?

Macrovalocytes

Hypersegmented neutrophils

29

How is megaloblastic anaemia treated?

Treat underlying cause e.g diet, malabsorption

Vit B12 injections in pernicious anaemia

Folic acid supplements

30

What are some causes of isolated macrocytosis?

Alcohol

Liver disease

Hypothyroidism