37 - Heritable Bleeding Disorders Flashcards
Vascular/Platelet defect clinical presentation
Petechiae & superficial bruises
Skin and mucosal membranes
Spontaneous
Bleeding immediate, prolonged + recurrent
Coagulation defect - clinical presentation
Deep spreading haematoma
Haemarthrosis (bleeding into joint spaces)
Retroperitoneal bleeding
Bleeding prolonged and often recurrent
Petechiae - what does it look like?
Do not blanch with pressure
Not palpable
Types of von Willebrand disease
Absent molecule - severe
Reduced production of normal molecule
Low molecular weight polymer
What factor is associated with VWF? What is this protein responsible for?
FVIII - carrier protein
FVIIIa responsible for turning FIXa into FX
VWF - inheritance pattern
AD
VWF features
Most common heritable bleeding disorder
Mainly AD
Men + Women
Defective primary haemostasis
Menorrhagia
Post op and post partum bleeding
VWF which blood group has lower levels of vWF?
O blood group
Treatment of vWF
Antifibrinolytics DDAVP - for type I vWD Factors containing concentrates of vWF Vaccination against hepatitis COCP (combined oral contraceptive pill) for menorrhagia
Haemophilia inheritance factors
XL recessive
Haemophilia A - factor affected and prevalence
Factor VIII deficiency
1in 5,000 males
Haemophilia B - factor affected and prevalence
Factor IX deficiency
1 in 30k males
Extrinsic clotting factors
Tissue factor (thromboplastin)
Ca2+
Factor VII
Intrinsic clotting factors
Factor XII, XI, IX, VIII
Platelets
Phospholipids
Ca3+
What % of haemophilia diagnoses are de novo?
30%
Types of bleed
Spontaneous/post-traumatic Joint bleeding = haemarthrosis Muscle haemorrhage Soft tissue Life threatening bleeding
Haemophilia - treatment
Replacement of missing clotting proteins - on demand or prophylaxis
DDAVP (desmopressin) - mild/mod haemoA
Factor concentrates
Antifibrinolytic agents
Vaccination vs hep AandB
Supportive measures
Incidence of inhibitor development in Haemo(x)
25% in haemo A
What is inhibitor development?
Antibodies fight the factor concentrates
Can’t use factor concentrates
Effects of inhibitor development
Results in poor recovery and short half of factor replacement therapy
Specialised management of bleeds needed
Eradication of inhibitor required via immune tolerance
Genetic predisposition makes susceptible
Investigations for haemophilia
FBC and blood film
Coag screen
Refer to haematologist if history suspicious
Inhibitor assays
Platelet function tests
