Haemoglobinopathy Flashcards Preview

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Flashcards in Haemoglobinopathy Deck (26):
1

Describe the structure of haemoglobin?

2 alpha globin like chains
2 beta globin like chains

2

What is the ratio of haem to globin in haemaglobin?

One haem attached to each globin chain

3

What chromosome is the alpha like gene expressed on?

16

4

What chromosome is the beta like gene expressed on?

11

5

At what age do you reach adult levels of haemaglobin?

6 - 12 months

6

What are the two main groups of haemaglobinopathies?

Thalassaemia - decreased rate of globin chain production
Structural haemoglobin variants - normal production of structurally abnormal globin chains

7

What are the two types of thalassaemias?

Alpha thalassaemia
Beta thalassaemia

8

What kind of anaemia do you get with thalassaemia?

Microcytic hypochromic anaemia

9

Why do you get alpha thalassaemia?

Deletion of one or both of the alpha genes from chromosome 16

10

Why do you get reduced synthesis alpha thalassaemia?

Deletion of one of the alpha genes from chromosome 16

11

Why do you get absent synthesis alpha thalassaemia

deletion of both genes from chromsome 16

12

What is the most severe form of alpha thalassaemia?

HbH disease
(only 1 working alpha gene per cell)

13

What supplement do you need to give in alpha thalassaemia?

Folic acid (increased RNC turnover creates an increased demand)

14

How is beta thalassaemia usually caused?

Point mutation

15

How is beta thalassamia inherited?

Autosomal recessive

16

What is the diagnostic test for beta thalassaemia trait?

Raised HbA2

17

What does bet thalassaemia lead to if not diagnosed early?

Extramedullary haematopoiesis

18

How do you manage beta thalassaemia?

Regular transfusions to maintain the haemoglobin above 95g/L so as to suppress ineffective arythropoiesis and inhibit gut over absorption of iron.

19

What drugs are given in beta thalassaemia?

Iron
Iron cheleating drugs such as desferrioxamine

20

How is sickle cell anaemia inherited?

Autosomal recessive

21

What kind of mutation is seen in sickle cell anaemia?

Point mutation in codon 6 of the beta globin gene

22

How many abnormal genes do you have in sickle cell trait?

One

23

What are the precipitants of a sickle crisis?

Hypoxia
Dehydration
Infection
Cold exposure
Stress/Fatigue

24

What are the symptoms of sickle cell disease?

Tissue infarction due to vascular occlusion (symptoms dependent on site and severity)
- Digits
- Leg ulcers
- Sever pain

25

What is the treatment of a painful sickle cell crisis?

Opiate analgesis
Hydration
rest
Oxygen
Antibiotics if infection
Red cell exchange transfusion in sever crisis (chest crisis or neurological crisis)

26

What are the long term effects of sickle cell disease?

Poor growth
Infection (hyposplenism)
Organ damage
Psychosocial problems