Haem - Misc Haem Flashcards
What is thalassaemia
Abnormal transcription of either a or b globin genes
Excessive production of the other
Chains precipitate in red cell —> haemolysis and anaemia
Normal globin chains and how they change
4 a and 2 b globin normally
Disesae apparent at 3-6 months when HbF —> HbA
Alpha thal -> deletion of between 1-4 globin chains.
Severity varies
all 4 - death
Beta thal - reduced production of b globin chains.
Excess alpha binds remaining beta, deta or gamma chains.
HbA2 —> delta and HbF—> gamma form.Heterozygous —> minor (mild microcytic anaemia with Hb 20-30 below)
Homozygous —> major (profound anaemia, transfusion dependent)
Considerations for thallasaemia
1) transfusion support Threshold ins 95-100 g/l
2) infection prevention and control May have had a splenectomy
3) Beware yersinia infection —> in presence of iron overload —> suspect with diarrhoea
4) Iron overload —> hepatic impairement and cardiomyopathy Desferrioxamine chelates iron
What is factor V leiden
Factor V — protein in coag cascade and produces thrombin.Inactivated by activated by protein C
Leiden - autosomal dominant—> produces mutated Factor V
APC cannot degrade it —> ongoing clot formation and thrombophilia.
Typical VTE, arterial rare
What is antiphospholipid
Autoimmune hypercoagulable stae
Presence of anti-phospholipid antibodies
Arterial or venous thrombosis/. Pregnancy loss, IUGR etc
Catastrophic —> generalised thrombosis —> MOF
Primary or Secondary to other autoimmune disease —> SLE
Diagnositc criteria for AntiPhospholipid Syndrome
1 clinical event (thrombotic or pregnancy)
2 antibody tests
3 months aparts confirming: Lupus anticoagulant Anti b2 glycoprotein1 (subset of anticardiolipin)
Treatmnent of APS
Asprin
Anticoagulation
PLex in catastrophic
Patho of haemaphilia
Deficiency of coag factors Inherited oin X linked recessive fashion —> only affect males
Type A —> deficiency of Factor 8
Type B —> deficiencty of Factor 9
Disease severity on quantification of clotting factor levels Mild (5-50%, mod 1-5%, severe <1%)
How do haemaphiliacs present to ICU
Severe bleeding (post op, trauma)
Complications of haemorrhage or massive transfusion
Haemarthroses and muscle haematomas
How to manage haemophilia in ICU
Even if no bleeding - conintue there clotting factor concentrate prophylaxisMaintain clotting factor levels >50%If doing an intervention, bolus doses to >100%Can consider TXADDVAP —> increases factor 8 Good for haemophilia A but not B
What is von Willibrands
Most frequent hereditary coagulopathy 1%AD inheritence, quant and sometimes qual deficiency of vWF.Normally vWF made my plts and vascular endothelium. Needed for plt adhesion to subendotheliumBinds factor VII to prevent its breakdownUsually presents as mucosal bleeding - dental, menorrhagia etc.Treat with prophylacitc DDAVP and factor 8 concentrate
Types of vWD
Type 1 - AD - 85% - mild mod loss of vWF
Type 2 - AD - 15% - functional defect of vWF
Type 3 AR - Rare - severe deficeincy of vWF
