Normocytic and Macrocytic Anaemia + Some Blood Parameters

Question 1

How do we assess haematological parameters

Answer 1

Venous sample

Finger prick or heel prick sample

Question 2

WBC

Answer 2

White blood cells in a given volume of blood x10^9 /l

Question 3

RBC

Answer 3

Red blood cells in a given volume of blood x10^12/l

Question 4

Hb

Answer 4

Haemoglobin concentration g/l

Question 5

Hct

Answer 5

Haematocrit in a %

Question 6

MCV

Answer 6

Mean cell volume fl

Question 7

MCH

Answer 7

Mean cell haemoglobin pg

Question 8

MCHC

Answer 8

Mean cell haemoglobin concentration g/l

Question 9

Platelet count

Answer 9

Measured in a x10^9/l

Question 10

How do we measure haemoglobin

Answer 10

Automated instrument

- initially measured in a spectrometer by converting into a stable state and then measuring absorption

Question 11

Measuring Hct

Answer 11

Measured by centrifuging a blood sample and then using the scale to see the volume percentage of red blood cells in a given sample

Question 12

What does polycythaemia mean

Answer 12

It means too many red cells in circulation

Hb RBC Hct are increased

Question 13

What are the two types of polycythaemia

Answer 13

Pseudo- reduced plasma volume

True - increase of total volume of red cells in circulation

Question 14

What can cause increase in total volume of red cells in circulation

Answer 14

Blood doping or overtransfusion
Appropriately increased erythropoietin - as a result of hypoxia. At high altitudes this is beneficial
Inappropriately synthesis or use of erythropoietin - when administered, or when kidney or other tumour secretes it.
Independent erythropoietin - intrinsic bone marrow disorder polycythaemia Vera. A myoproliferative disorder. Lead to thick blood and hyper viscosity and can lead to vascular obstruction and venous or arterial thrombosis. Blood can be removed by venosection. Drugs can be given to reduce production of bone marrow red cells (mutation that prevents erythropoietin to bind to the receptors, JAK2 gene time, mainly disease of the elderly)

Question 15

How do we calculate MCV ?

Answer 15

=Hct x 1000
———————-
RBC

Question 16

What are macrocytic cells?

Answer 16

They are larger than normal. And the MCV tends to be larger.
Always compare with what is appropriate for that age. Babies are born much larger red cells than children or adults and their cells would only be considered as macrocytic if their MCV was above a normal range in neonates.
They results from abnormal haemopoiesis so the red cell precursor continue to synthesis haemoglobin and other cellular proteins but fail to divide properly.

Question 17

What are the causes of macrocytosis and anaemia

Answer 17

Megaloblastic anaemia
Macrocytic anaemia
Stress erythropoiesis

Question 18

What is megaloblastic erythropoiesis?

Answer 18

Specifically delay in maturation of the nucleus, while the cytoplasm continues to mature and the cell continues to grow. Shows megalocytoplasmic dissociation.
Megaloblastic seen in the bone marrow not in the blood film

Can be caused by B12 or folate deficiency from peripheral blood features but be sure to do a bone marrow examination

Question 19

What causes macrocytic anaemia?

Answer 19

Lack of vitamin B12 and folic acid (megaloblastic anaemia)
Use of drugs interfering with DNA synthesis
Liver disease and ethanol toxicity
Recent major blood loss with adequate iron stores (reticulocytes increased)
Haemolytic anaemia (reticulocytes increased) — young cells such as polychromatic and reticulocytes are 20% larger which means that the MCV will be increased in the blood count calculations.

Question 20

Where is B12 found and how much do we need

Answer 20

1milligram but need 2.4 as not all of it is absorbed
Animal products
Fortified cereals

Question 21

Where does deficiency result from

Answer 21

Veganism
Lack of acid in stomach ( is required to cleave it and release it from food in the first step)
Inadequate secretion if pernicious anaemia
Malabsorption coeliac disease

Question 22

Where is folate found

Answer 22

Green leafy veg 
Cauliflower 
Brussels sprouts 
Liver kidney 
Whole grain cereals 
Yeast 
Fruit

Question 23

How much folate do we need

Answer 23

50 micro grams but need to intake about 400-600
Absorbed maximally in the jejunum
Total body stores are 3-4 months

More needed in pregnancy and sickle cell anaemia

Question 24

Where is folate lost from

Answer 24

Urine, bile cells from skin and intestine

Question 25

What is the role of folic acid (a bit of extra information)

Answer 25

Transfer single carbon groups, essential for synthesis of purines and pyrimidines, and for inconventions of amino acids
Reduced rate of DNA synthesis, with serious pathological effects particularly in haemopoetic cells

Question 26

What are the mechanisms of normocytic anaemia

Answer 26

Recent blood loss - trauma and GI bleeding
Failure to produce red cells - early stage of iron deficiency, bone marrow failure or suppression eg chemotherapy, bone marrow infiltration
Pooling of red cells in the spleen - hypersplenism eg liver cirrhosis and in splenic sequestration in sickle cell anaemia

Question 27

How do we count reticulocytes

Answer 27

Stain with methylene blue which stains higher RNA content of red blood cells so they can be counted. Similiar thing for polychromasia

Question 28

When is an increased reticulocyte count seen?

Answer 28

Haemolytic anaemia
Recent blood loss
Response to treatment with iron, B12 or folate

Question 29

When is a reduced reticulocyte count seen

Answer 29

Reduced output of red cells from the bone marrow

Question 30

What happens at the end of the life of red cells

Answer 30

Phagocytosed by the spleeen
Haem -> bilirubin -> excreted in bile
Iron made to transferring and returned to bone marrow
Globin -> hydrolysed to amino acids

Question 31

4 mechanisms that can result to anaemia

Answer 31

Reduced production of red cells by the bone marrow - deficiency of iron, B12 leukamia, folate

Loss of blood from the body - GI bleeding, heavy menstrual bleeding

Reduced survival of red cells in circulation - sickle cell disease, G6PD deficiency, hereditary spherocytosis

Increased pooling of red cells in enlarged spleen - splenic sequestration in children