Haemoglobinopathies - sickle cell anaemia Flashcards
2 conditions that will be focused on?
Sickle cell
Thalassaemias
What type of anaemia do sickle cell disease and thalassaemias cause?
Congenital causes haemolytic anaemia
What is sickle cell, what is its mutation?
Mutations leading to structurally abnormal globin chain
point mutation in the beta gene
majority are autosomal recessive
glu-> valine
Haemoglobinopathies?
a group of inherited blood disorders involving the haemoglobin, the protein of red blood cells.
What rbcs are caused by sickle cell?
Painful vaso-occlusive crises caused by sickle cell disease?
- Bone pain
- Hand- foot syndrome
Stroke - affects children
Effects of sickle cell anaemia? (general)
Chronic haemolytic anaemia
Increased infection risk
Reduced life expectancy
Vaso-occlusive crises
organ damage due to microinfarcts
reduced life expectancy
Effects of chronic haemolytic anaemia? - sickle cell disease
Gallstones
Aplastic cross
- organ damage due tot microinfarcts
Infection in relation to sickle cell disease?
Hyposplenism
Osteomyelitis
Dental abnormalities and sickle cell disease?
Sickling in jaw mimicking dental pain
Facial swelling during crisis
Tooth pulp affected by sickling
Increased risk of infection
Delayed eruption and hypolasia of dentition
Management of sickle cell disease?
General considerations
- hydration
- oxygenation
- analgesia
Life long prophylaxis against infection
- vaccination
- penicillin (and malarial prophylaxis)
Folic acid
Blood transfusion - prior to major surgery and ga
- especially pain in lungs/chest
GENE THERAPY
Allogeneic blood transfusion can cure
Pt with sickle cell - morning or afternoon app?
Morning (well rested)
Pt with sickle cell advise before dental work?
liase with haematology consultant in advance
Morning app
Recommend good fluid intake prior to procedure
LA preferred option
Adequate analgesia
Antibiotics to cover invasive tx
avoidance of hypoxia and hypothermia around GA
- LA
What are the units making haemoglobin?
2 alpha chians
2 beta chains
genes for the 2 alpha chains?
4 alpha genes
genes for the 2 beta chains?
2 beta genes
What is fetal haemoglobin gene combination?
alpha-gamma (aayy)
2 main causes of haemoglobinopathies?
mutations leading to structurally abnormal globin chain:
- HbS(sickle cell)
reduced or absent globin chain production
- thalassaemia
types of thalassaemia?
dependent on the absent/reduced globin chain
alpha a
- alpha thalassaemia
beta b
delta d
gamma y
Inheritance of sickle cell disease?
majority are autosomal recessive
What does mutated beta chain and alpha chain combining cause?
HbS
Effect of HbS on RBC morphology?
RBC biconcave makes the RBC flexible
sickle cell, in times of stress or low oxygen concentration: haem crystallises causes RBC to become rigid ‘sickly’ shape
cant squeeze through micro-vasculature and causes vaso-occlusion
Types of sequestration crises caused by sickle cell anaemia?
spleen
liver
when is blood transfusion indicated in sickle cell?
before major surgery under GA
