Sickle-cell anaemia Flashcards
What is sickle cell anaemia?
Autosomal recessive condition that causes sickle (crescent) shaped red blood cells.
What type of inheritance does sickle cell anaemia have?
Autosomal recessive
What do red blood cells being sickle shaped mean?
It means they are fragile and more easily destroyed leading to an haemolytic anaemia.
What are patients with sickle cell anaemia prone to?
Sickle cell crises
What is the genetic cause of sickle cell anaemia?
Glutamic acid is replaced by valine on the 6th position of the β chain.
Resulting in an abnormal gene for beta-globin on chromosome 11
What type of mutation results in sickle cell anaemia?
Point mutation
What does one copy of the abnormal gene result in?
Sickle cell trait Hb AS (carrier)
What is required for sickle cell disease?
Two abnormal copies of the gene HbSS
How is sickle cell anaemia diagnosed in a new born?
Heel prick test at 5 days of age
Who would be offered a gene test?
Women at risk of being carries are offered a gene test when pregnant
What are some possible complications of sickle cell anaemia?
- Anaemia
- Increased risk of infection (due to hyposplenism)
- Stroke (one of the commonest causes in children)
- Avascular necrosis in large joints such as the hip
- Pulmonary hypertension
- Priapism
- Chronic kidney disease
- Sickle cell crises
- Acute chest syndrome
What are sickle cell crises?
An umbrella term for a spectrum of acute crises related to the condition.
How can sickle cell crises occur?
They can be spontaneous
Or
Triggered by stresses- infection, dehydration, cold or significant life events.
What are some examples of sickle cell crises?
- thrombotic, ‘painful crises’
- sequestration
- acute chest syndrome
- aplastic
- haemolytic
What is the most common acute presentation of sickle cell crises?
Thrombotic crises (Vaso-occlusive Crisis (AKA painful crisis))
