Thalassaemia Flashcards
Define thalassaemia major
Homozygous for beta thalassaemia
2x defective beta globulin genes
Severe iron deficiency anaemia requiring >7 transfusions a year
Define beta thalassaemia intermedia
Homozygous for beta thalassaemia
2x defective beta globulin genes
Spectrum with variable transfusion requirements - <7 a year
Describe the spectrum of disease severity seen with thalassaemia intermedia
Severe: diagnosed 2-6yr, with impaired growth and development
Mild: diagnosed in adulthood, often incidental finding with hepatosplenomegaly and mild anaemia
Define thalassaemia minor
Heterozygous defective beta globulin gene
Mild to moderate microcytic anaemia
What is the effect of iron overload on the anterior pituitary
Delayed or incomplete puberty
Hypogonadotrophic hypogondadism
Leading to anovulatory infertility
Low bone mass due to hypo-oestrogenic state
What is the cause of death in 50% of people with thalassaemia major
Cardiac due to iron overload
Regarding thalassaemia major
What contraception is contraindicated
None
Regarding thalassaemia major
What chelating agents can be used in pregnancy
None in first trimester
Desferrioxamine in second and third trimester
Regarding thalassaemia major
What monitoring is used for diabetes
What preconception target is used
Fructosamine
Aim for <300 for 3/12 prior conception
Equivalent to hba1c of 43
Regarding thalassaemia major
What are the important cut off values when assessing cardiac iron
Aim for T2 cardiac MRI >20ms
If <10ms high risk of cardiac failure
Regarding thalassaemia major
Which patients are particularly at risk of arrhythmias
Older, previous significant iron overload since cleared
Regarding thalassaemia major
What are the important cut off values in assessing liver iron overload
Aim for liver iron <7mg/g
If >15mg/g increased risk of cardiac overload, therefore chelation preconception or 20-28 weeks
Regarding thalassaemia major
What % have RBC alloimmunity
16%
Regarding thalassaemia major
What vaccines are required and how often
Hep B if transfusion requirements
Pneumococcus every 5 yr
Haemophilus influenza if not previous
Meningococcal c if not previous
Regarding thalassaemia major
If diabetic how often should fructosamine be tested
Monthly
Regarding thalassaemia major
How often should patients be reviewed antenatally
Monthly till 28 weeks then every two weeks till delivery
Regarding thalassaemia major
When should they have US scans in the antenatal period
7-9 weeks due to increased risk of early Pregnancy loss
Routine dating and anomaly
Growth scans 4 weekly from 24 weeks
Regarding thalassaemia major
What pre transfusion Hb should you aim for
Hb 100
Regarding thalassaemia intermedia
When should you consider starting regular transfusions
FGR
Worsening anaemia
Regarding thalassaemia intermedia
If transfusing
What pre transfusion Hb should be aimed for
How many units should initially be given
Aim for pre transfusion Hb of 100
Start with 2-3 units
Regarding thalassaemia intermedia
If transfusing
How often should Hb be monitored
How many units should be given if Hb <100
Every 2-3 weeks
2 units of Hb <100
Regarding thalassaemia intermedia
If not transfusing regularly what Hb cut off should be used to transfuse
If Hb <80 weeks give 2 units at 37-38 weeks
Regarding thalassaemia
What thromboprophylaxis should be given
If splenectomy or platelets >300 give aspirin
If splenectomy & platelets >300 give aspirin & LMWH
Regarding thalassaemia
Which patients are at highest risk of thrombosis
Splenectomy and no regular transfusions
High levels of peripheral RBC fragments
Regarding thalassaemia patients
What is the intrapartum management
Continuous CTG monitoring
If Hb <100 cross match 2 units
If transfusion dependant desferrioxamine throughout labour - 2g over 24 hours
Active management third stage
Regarding thalassaemia patients
What thromboprophylaxis should be given postpartum
LMWH
7 days following d/c if NVD
6 weeks following d/c if LSCS
Regarding thalassaemia patients
When should desferrioxamine be restarted
As soon as 24hr IV infusion completed if breastfeeding
If not breastfeeding continue IV until discharge, then resume pre pregnancy iron chelation therapy
What is the most accurate screening blood indices for thalassaemia trait
MCH mean corpuscular haemoglobin
