Haemoglobin disorders Flashcards Preview

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Flashcards in Haemoglobin disorders Deck (10):
1

Normal haemoglobin

HbA = 2x alpha and 2x beta - 98% in adults

HbA2 = 2x alpha and 2x delta - 2-3%

HbF = 2x alpha and 2x gamma - neonates

2

Alpha Thalassaemia summary

Reduced alpha globin production
--> reduced HbA, HbA2 and HbF

4 genes -
-> 3 disease states - Trait, HbH disease and hydrops fetalis

Trait = 2 or more functioning genes = clinically silent

China and South-east Asians

3

HbH disease

HbH disease = 1 functioning copy of alpha gene

Chronic haemolysis and splenomegaly
Low Hb
Low MCV
HbH cells on BF
HbH on HPLC
Confirm with gene studies

4

Beta Thalassaemia summary

Reduced beta globin production
--> reduced HbA

2 beta genes
--> 2 disease states - minor/trait and major

Mediterranaean and South East Asians

5

Beta Thalassaemia Minor

Reduced HbA with compensatory increase in HbA2

Clinically asymptomatic

Mild anaemia on film - low MCV and MCH
Target cells on film
HPLC = increased Hb A2 and Hb F

6

Beta thalassaemia Major

Absent or severe deficiency of HbA

Requires transfusions from 3-6 months

Haemolysis
BM expansion
Extra medullary haemopoeisis
Developmental delay

Severe Hb loss - 30-70
Low MCV and MCH
anisopoikilocytosis
HPLC --> elevated HbA2 and Hb F no HbA

Treatment:
- transfusions
- Fe chelation
- Autologous SCT
- Endocrine and bone and thrombotic disease

7

Sickle cell Anaemia pathogenesis

Changes of GAG to GTG on the beta globin gene

--> HbS
--> HbS polymerises into long fibres on deoxygenation
--> distorted sickle like erythrocyte



Autosomal recessive disease - need 2 copies of HbS for disease

African heritage

Treatment:
- Hydroxyurea
- Transfusion

8

Sickle cell disease presentation?

Vaso-occulsion disease most common

Acute chest syndrome
Haemolysis

SICKLE CRISIS
Can be triggered by parvovirus

9

Most common side effect of blood transfusion?

Circulatory overload

10

Other side effects of blood transfusion?

ABO incompatibility - clinical error at the bedside

Bacterial contamination
Transfusion acquired infections