2.6 Bleeding disorders Flashcards
Descibre adhesion
Platelet GPIb-V-Ix binds matrix vWF at high shear causing reversible binding causes adhesion to exposed ECM
Describe Activation
Adhesion triggers GPIIb-IIIa activation causing irreversible binding to matrix ligands, shape changes and platelet activation
Describe Aggregation
Activated GPIIb-IIIa mediates aggregations via fibrinogen, vWF causing release of granule contents, Microparticles and the recruitment of additional platelets and triggers coagulation
What causes Haemophilia A and B?
A: Factor VIII deficiency
B: Factor IX deficiency
What is the inheritance of haemophilia A?
X linked recessive
What is the classification of haemophilia A?
Mild: >5% normal levels fVIII
Moderate: 1-5%
Severe:
What are the clinical manifestations of mild, moderate and severe haemophilia A?
Mild: post trauma/surgical bleeds, spontaneous bleeding uncommon
Moderate: Occasional spontaneous joint bleeds, post traumatic bleeding
Severe: frequent spontaneous bleed from early life, potential joint deformity
What are the symptoms of chronic haemophilic arthropathy?
Loss of joint movements Fixed flexion contractures Severe muscle wasting Muscle action imbalance Crippling deformaties
What is the treatment for haemophilia A?
Infusion of factor VIII for prophylaxis
Can also give whole blood, plasma, cryoprecipitate, plasma derived factor VIII, recombinant f VIII, gene therapy
What are the complications of haemophilia A?
Recurrent joint bleeding - arthropathy
Severe: increased risk of death from other bleeding events such as intracranial haemorrhage
What are the diagnostic factors of haemophilia A and B?
Prolonged APTT and factor assays to confirm deficient factor
Which is more common, Haemophilia A or B?
A
Which is more common, Haemophilia A or B?
A
What are the two roles of vWF?
Carrier protein for Factor VIII
Promote platelet adhesion to subendothelium at high shear rates
What is the most common inherited bleeding disorder?
Von Willebrands Disease
