Haemoglobulinopathies Flashcards
(26 cards)
What are the 2 Haemoglobulinopathies that we are going to discuss?
Sickle cell anaemia and Thalassaemia
What is a haemoglobulinopathy?
Hereditary condition involving an abnormality in the structure of haemoglobin, in other words a structurally abnormal globulin chain
How is Sickle cell anaemia inherited?
Autosomal Recessive fashion
So if there are 2 carrier parents of SCD what is the chance of an effected child and a carrier child?
1 in 4
1 in 2
What do the Hb chains look like in SCD?
2 alpha chains and 2 Beta sickle chains
w=What is the basic pathophysiology in SCD?
RBCs contain Hbs, when when the cells become oxygenated they sickle, when they re-oxygenate again they DO nOT return to their normal biconcave shape and therefore cannot carry as much oxygen
What is HbSS polymerisation?
There is red cell damage, cation loss and dehydration leading to haemolysis
This causes endothelial activation, inflammation, activation of coagulation, dysregulation of vasomotor tone and then VASO-OCCLUSION
What is the prevalence and the affected group in SCD?
1/700 of those form an African heritage
What are the features of a SCD crises?
Vaso-occlusove crises: causes severe pain in the bones
Chest crises: Chest pain, fever and worsening hypoxia
Stroke, infections, aplastic crises after parvovirus
What are other clinical findings of SCD?
Retinopathy Cerebral infarcts Cardiomegalu and congestive HF Pulmonary infarcts and pneumonia Splenomegaly Ulcers Bone necrosis
What is THE diagnostic test f SCD?
Sickle cells disease
Often high Bilirubin
What tests are you going to do un a crises?
CXR infiltrates
Infection: blood cultures and parvovirus B19 screen
What is the long-term prophylaxis of SCD?
Vaccinations Penicillin and anti-malarial Folic acid Sometimes blood transfusion DMD: hydroxycarbimide Only cure is BONE MARROW TRANSPLANT
What is the management of general crises?
Hydration Oxygenation Prompt treatment of infection analgesia Thromboprophylaxis
What is the management of a bone Crises?
Give analgesia within 30 mins of presentation
Hydration and oxygenation
What is the management of a chest crises?
Respiratory support, antibiotics and IV fluids’ analgesia and transfusion
What is the life prognosis of someone with SCD?
Decrease in life expectancy
M = 42yo
F = 48yo
Most live to 18
What is the defining features of thalassaemia’s?
This is a haemoglobulinopaty where there is abnormal or no production of one of the globulin chains causing haemolysis whilst the cells are still in the bone marrow
What are the 2 types of thalassaemias
Alpha and Beta
What do the chains look like in alpha?
- α/αα “α+”: one alpha gene gone
- -/αα “α0”: both gone
What are betaT’s usually caused by?
A point mutation in the beta globulin on chromosome 11, causing lack of beta chain
What are the defining features of beta thalassaemia major?
Severe anaemia Presents at 3-6 months of age Expansion of ineffective bone marrow Bone deformities Splenomegaly Growth retardation
What are the 2 types of beta thalassaemias?
Minor and major
What is the diagnostic test of thalassaemia?
Hypochromic Microcytic RBC’s with NORMAL ferritin
