Microcytic Anaemia

Question 1

What is the Hb criteria for anaemia for males?

Answer 1

<130g/L

Question 2

What is the Hb criteria for anaemia for females?

Answer 2

<120g/L

Question 3

When are Hb and Hct not good markers for anaemia?

Answer 3

when its not in steady state eg rapid blood loss

or in haemodilution

Question 4

How is the response to anaemia measured?

Answer 4

reticulocyte count

Question 5

What leads to a microcytic anaemia?

Answer 5

shortage in globin or heme (porphyrin ring and iron)

Question 6

What is microcytic anaemia?

Answer 6

low MCV

hypochromatic

Question 7

What causes a microcytic anaemia?

Answer 7

Heme deficiency - iron deficiency + anaemia of chronic disease
porphyrin ring synthesis - lead poisoning, pyridoxine responsive anaemia, sideroblastic anaemia
globin deficiency - thalassaemia

Question 8

What is the role of iron?

Answer 8

oxygen transport - Hb and myoglobin

electron transport - mitochondrial production of ATP

Question 9

What is iron stored in in the liver?

Answer 9

Ferritin

Question 10

What is iron stored in in the body?

Answer 10

haemaglobin

Question 11

What is circulating iron bound to?

Answer 11

transferrin

Question 12

What does transferrin pass iron onto?

Answer 12

bone marrow macrophages that feed it to red cell precursors

Question 13

What are the properties of transferrin?

Answer 13

protein with two binding sites for iron atoms
transports iron from donor tissues (macrophages, hepatocytes + intestinal cells) to tissues expressing transferrin receptors

Question 14

How do you measure iron supply?

Answer 14

% saturation of transferrin with iron

Question 15

How do you measure iron storage?

Answer 15

serum ferritin

Question 16

How does ferritin react to acute inflammation/disease?

Answer 16

increases so binds lots of iron so the bacteria cannot feed on the iron

Question 17

What are the causes of iron deficiency anaemia?

Answer 17

menorrhagia
GI - tumours, ulcers, NSAIDs
haematuria
coeliac disease - not absorbing enough from proximal small bowel

Question 18

How many mg a day do you need iron intake wise?

Answer 18

1mg a day

Question 19

What ml of blood and mg of iron do you lose on average each menstrual cycle?

Answer 19

30-40ml

15-20mg iron

Question 20

What are the consequences of iron deficiency?

Answer 20

epithelial changes - dry skin and koilonychia of nails
microcytic anaemia
iron deficient erythropoesis
exhaustion of iron stores

Question 21

What are the different variants of Hb?

Answer 21

HbA
HbF
HbA2 - 2 aplha 2 delta

Question 22

What chromosome are alpha genes found? How many per chromosome?

Answer 22

chromosome 16

2 genes per chromosome 4 per cell

Question 23

What chromosome are beta genes found? How many per chromosome?

Answer 23

chromosome 11

1 gene per chromosome 2 per cell

Question 24

What are haemoglobinopathies?

Answer 24

abnormal globin chain synthesis caused by autosomal recessive disorders leading to microcytic anaemias

Question 25

What are the types of haemoglobinopathies?

Answer 25

thalassaemias | structural haemoglobin variants

Question 26

What are the two types of thalassaemias?

Answer 26

alpha and beta

Question 27

What is an alpha thalassaemia?

Answer 27

will result from deletion of 1 alpha or both | i.e. can be reduced chain production or absent chain production

Question 28

What are the 3 types of alpha thalassaemias?

Answer 28

``` alpha thalassaemia trait (-a,aa) HbH disease (--,-a) Hydrops foetalis (--,--) ```

Question 29

How does Alpha thalassaemia trait present?

Answer 29

asymptomatic | microcytic hypochromatic cells with a mild anaemia

Question 30

What treatment is required for Alpha thalassaemia trait?

Answer 30

NONE

Question 31

How is Alpha thalassaemia trait distinguished from iron deficiency anaemia?

Answer 31

ferritin

Question 32

How does HbH disease present?

Answer 32

more severe anaemia with very low MCV and MCH jaundice and splenomegaly

Question 33

Where is HbH disease common?

Answer 33

SE asia

Question 34

How is HbH disease treated?

Answer 34

splenectomy transfusions folic acid 1mg

Question 35

What is Hydrops foetalis?

Answer 35

no alpha chain to bind to so tetramers of Hb Barts and HbH produced most severe form

Question 36

How does Hydrops foetalis present?

Answer 36

``` profound anaemia cardiac failure skeletal and CUS abnormalities growth retardation severe hepatosplenomegaly BUT NORMALLY PICKED UP ON ANTENATAL SCREENING AND DIE IN UTERO ```

Question 37

What are the types of beta thalassaemia?

Answer 37

b thalassaemia trait (B+/B) or (B0/B) b thalassaemia intermedia (B+/B+) or (B0/B+) b thalassaemia major (B0/B0)

Question 38

What causes beta thalassaemia?

Answer 38

disorder of B chain synthesis, usually caused by point mutations can be reduced (B+) or absent (B0) B depending on the mutation

Question 39

What type of Hb does beta thalassaemia affect?

Answer 39

adult Hb - 2 alpha 2 beta

Question 40

How does b thalassaemia trait present?

Answer 40

asymptomatic | mild/no anaemia

Question 41

How is b thalassaemia trait tested for?

Answer 41

raised HbA2 in blood

Question 42

How does b thalassaemia intermedia present?

Answer 42

moderate anaemia - jaundice and splenomegaly

Question 43

How is b thalassaemia intermedia treated?

Answer 43

transfusion ocassionaly

Question 44

How does b thalassaemia major present?

Answer 44

severe anaemia 6-24 months as HbF falls failure to thrive, pallor, hepatomegaly, organ changes and skeletal changes - all due to extramedullary haematopoesis

Question 45

How is b thalassaemia major treated?

Answer 45

lifelong transfusion

Question 46

What is the main problem with b thalassaemia major?

Answer 46

iron overload from transfusion

Question 47

How does iron overload present?

Answer 47

endocrine dysfunction - diabetes, osteoporosis, cardiac disease, liver disease

Question 48

How do you treat iron overload?

Answer 48

iron chelating drugs - desferioxamine