Sickle Cell Anaemia Flashcards
what is the cause of sickle cell anaemia?
Two abnormal β genes (βs/βs)
what is the inheritance pattern of sickle cell anaemia?
autosomal recessive
What is the haemoglobin present in sickle cell anaemia?
HbS
what is the result of HbS in red blood cells?
Causes red blood cell to change shape (crescent moon) - more susceptible to be destroyed
what is the pathophysiology of sickle cell anameia?
Val replaces Glu - hydrophobic rather than hydrophilic
Oxygenated = fine
Deoxygenated = changes cell shape allowing it to aggregate with other HbS forming long polymers that distort blood cell shape
what are the clinical features of a sickle crisis?
o Digits (dactylitis), bone marrow, lung (acute chest syndrome), spleen, CNS
o Pain may be extremely severe
o Tissue ischaemia
what is a sickle crisis?
Episodes of tissue infarction due to vascular occlusion as cells stick together
what are the precipitants to a sickle crisus?
hypoxia, dehydration, infection, cold exposure, stress/fatigue, acidosis
chronic sickle cell disease has clinical fetaures of
- Chronic haemolysis
- Sequestration of sickled RBCs in liver and spleen
- Hyposplenism
- Cerebral vasculature – stroke and moya moya (puff of smoke = collateral vessels)
what is the management of an acute crisis?
Opiate analgesia Hydration Rest Oxygen Antibiotics if infection Red cell exchange transfusion in severe crises
what is the long term management of sickle cell disease?
o Hyposplenism -prophylactic penicillin, vaccination; pneumococcus, meningococcus, haemophilus
o Folic acid supplementation
o Hydroxycarbamide
o Regular transfusion
what are the complications of sickle cell disease?
- Impaired growth
- Risk of end-organ damage
- pulmonary hypertension
- renal disease
- avascular necrosis
- leg ulcers
- stroke
