Sickle-cell anaemia

Question 1

How is sickle cell anaemia inherited?

Answer 1

autosomal recessive

Question 2

Why is sickle cell disease more common in the African population

Answer 2

heterozygous condition offers some protection against malaria

Question 3

Pathophysiology of sickle cell disease

Answer 3

sickle cell trait (heterozygous) = HbAS
homozygous = HbSS

HbS molecules polymerise and cause RBCs to sickle

sickle cells block small blood vessels and cause infarction

Question 4

Definitive investigation to diagnose sickle cell disease

Answer 4

haemoglobin electrophoresis

Question 5

Management of sickle cell crises

Answer 5

analgesia e.g. opiates
rehydrate
oxygen
consider antibiotics
blood transfusion
exchange transfusion: e.g. if neurological complications

Question 6

Chronic Sickle cell disease management

Answer 6

hydroxycarbamide
- increases HbF levels

• pneumococcal vaccine every 5 years

Question 7

Name some different types of sickle cell crises

Answer 7

‘vaso-occlusive’
acute chest syndrome
aplastic
sequestration
infection

Question 8

What can precipitate a vaso-occlusive crisis

Answer 8

infection
dehydration
deoxygenation (e.g. high altitude)

Question 9

What happens in an acute chest crisis?

Answer 9

vaso-occlusion within the pulmonary microvasculature
=> lung infarction

Present with:
- SOB
- chest pain
- hypoxia

Question 10

Management of acute chest crisis

Answer 10

pain relief
oxygen
antibiotics
transfusion/ exchange transfusion

Question 11

Aplastic crises are associated with what virus?

Answer 11

parvovirus

Question 12

What happens in a sequestration crisis?

Answer 12

sickling within organs such as the spleen or lungs

=> blood pools in these organs and causes worsening anaemia

=> increased reticulocyte count to counteract this