Sickle Cell Disease Flashcards
At what point in gestation does production of HbF start to decrease?
32-36 weeks
What is the ratio of HbF and HbA at birth?
50:50
At what age does HbF stop being produced very much?
6 months
What is the abnormal haemoglobin variety called in sickle cell disease?
HbS
What type of genetic condition is sickle cell? E.g. dominant
Autosomal recessive
Where is the mutation found for sickle cell disease?
Abnormal gene for beta globin on chromosome 11
What is sickle cell trait?
Person only has 1 copy of defected gene
Carrier
Asymptomatic
In Which ethnic groups are sickle cell disease more common? (4)
Africa
India
Middle East
Caribbean
What is the relation of sickle cell disease to malaria?
Patients with sickle cell trait have reduced severity of malaria .: more likely to survive and pass gene on
Selective advantage
When is sickle cell disease screened for?
Newborn screening heel prick test at 5 days old
What are the complications of sickles cell disease? (9)
• Anaemia
• Increased risk of infection
• Stroke
• Avascular necrosis in large joints such as the hip
• Pulmonary hypertension
• Painful and persistent penile erection (priapism)
• Chronic kidney disease
• Sickle cell crises
• Acute chest syndrome
What is the conservative management of sickle cell disease? (3)
. Avoid dehydration and other triggers of crisis
. Ensure vaccines up to date (pneumococcal every 5 years)
• Antibiotic prophylaxis to protect against infection with penicillin V (phenoxymethypenicillin)
What drugs are used in the treatment of sickle cell disease? (2)
Hydroxycarbamide
Crizanlizumab
How does hydroxycarbamide manage sickle cell disease?
• Hydroxycarbamide can be used to stimulate production of fetal haemoglobin (HbF). Fetal haemoglobin does not lead to sickling of red blood cells. This has a protective effect against sickle cell crises and acute chest syndrome.
How does crizanlizumab manage sickle cell?
Crizanlizumab is a monoclonal antibody that targets P-selectin. P-selectin is an adhesion molecule found on endothelial cells on the inside walls of blood vessels and platelets. It prevents red blood cells from sticking to the blood vessel wall and reduces the frequency of vaso-occlusive crises.
What are some triggers of sickle cell crises? (4)
Infection
Dehydration
Cold
Significant life events
What is included in the management of sickle cell crises? (6)
• Have a low threshold for admission to hospital
• Treat any infection
• Keep warm
• Keep well hydrated (IV fluids may be required)
• Simple analgesia such as paracetamol and ibuprofen
• Penile aspiration in priapism
What is Vaso-occlusive crisis?
Vaso-occlusive crisis is caused by the sickle shaped blood cells clogging capillaries causing distal ischaemia.
What is Vaso-occlusive crisis associated with? (3)
Sickle cell
Dehydration
Raised haematocrit
What can Vaso-occlusive crisis cause in males?
Priapism = blood trapped in penis causing painful and persistent erection
How is priapism managed?
Aspiration of blood from the penis
What is a splenic sequestration crisis?
Splenic sequestration crisis is caused by red blood cells blocking blood flow within the spleen. This causes an acutely enlarged and painful spleen.
What can a splenic sequestration crisis lead to? (2)
Severe anaemia
Hypovolaemic shock
What is the management of splenic sequestration crisis? (2)
Blood transfusion for anaemia
Fluid resuscitation for shock
