Disorders of Haemostasis Flashcards
Give examples of minor bleeding symptoms
Easy bruising Gum bleeding Frequent nosebleeds (epistaxis) Bleeding after tooth extraction Post-operative
Give examples of minor bleeding symptoms in women
Menorrhagia
Post-partum bleeding
Family history
What are the elements of a significant bleeding history
Epistaxis not stopped by 10 minutes compression pr requiring medical attention/transfusion
Cutaneous haemorrhage or bruising with no trauma
Prolonged (>15min) bleeding from trivial wounds
Menorrhagia requiring treatment that leads to anaemia
Heavy, prolonged or recurrent bleeding after surgery or dental extraction
Why might abnormal haemostasis occur and give an example of how
Lack of a specific factor
Failure of production or increased consumption/clearance
Defective function of a specific factor
Genetic defect or acquire defect (drugs, synthetic defect, inhibition)
Give examples of disorders of primary haemostasis
- thrombocytopenia
- impaired platelet function
- vessel wall dysfunction
- loss or dysfunction of vWF
What may cause thrombocytopenia
Bone marrow failure: e.g. leukaemia, vitamin B12 deficiency
Increased use: e.g. disseminated intravascular coagulation (DIC)
Increased clearance: e.g. autoimmune thrombocytopenic purpura
Pooling of platelets in an enlarged spleen
What occurs in autoimmune thrombocytopenic purpura
Autoantibodies for platelets, causing their phagocytosis by macrophages
What may cause impaired function of platelets in primary haemostasis
Hereditary disorders of glycoproteins: e.g. Bernard-Soulier syndrome, absence of Gp1b
Drugs: e.g. aspirin, NSAIDS, clopidogrel
What can vessel wall dysfunction in primary haemostatic disorders be due to
Hereditary connective tissue disorders e.g. hereditary haemorrhagic telangiectasia (Ehlers-Danlos syndrome) Scurvy Steroid therapy Vasculitis Aging (senile purpura)
What are the functions of VWF in haemostasis
Binding to collagen and capturing platelets
Stabilising factor VIII (may be low if VWF is low)
Describe Von Willebrand Disease
Hereditary disease of vWF quantity or function
but can be caused by antibodies to vWF
May cause low VIII.
Describe the typical bleeding of primary haemostasis
Immediate Superficial bleeding into skin and mucous membranes e.g. nosebleeds Prolonged bleeding from cuts Epistaxes Gum bleeding Menorrhagia Easy bruising Prolonged bleeding after trauma or surgery
What might be the typical bleeding specific to thrombocytopenia and severe VWD
thrombocytopenia - petechiae
Severe VWD - haemophilia-like bleeding
Give some hereditary causes of secondary haemostatic disorders and state their effect
II (incompatible with life)
XI (more bleeding after trauma)
XII (no - adverse effects)
VIII or IX (haemophilia, see below)
Give some causes of secondary haemostatic disorders
Liver disease, because most factors are made there
Dilution of the blood
Anticoagulants: e.g. warfarin
Increased use: e.g. DIC (like for thrombocytopenia)
Describe disseminated intravascular coagulation
Generalised activation of coagulation – Tissue factor
Associated with sepsis, major tissue damage, inflammation
Consumes and depletes coagulation factors
Platelets consumed
Activation of fibrinolysis depletes fibrinogen
Deposition of fibrin in vessels causes organ failure
Describe the typical bleeding in coagulation disorders (Secondary)
Deep bleeding into tissues, muscles, and joints
Delayed bleeding after trauma, which is then prolonged
Often restarts after stopping
Which tests can be done for primary and secondary haemostasic disorders
Prothrombin time (PT)
Activated partial thromboplastin time (APTT)
Full blood count (platelets)
Tests for specific inhibitors
Describe the genetics for haemophilia
X-linked recessive
Describe the genetics for vWD
type 1 and 2 - autosomal dominant
type 3 - autosomal recessive.
What are some causes of fibrinolysis disorders
hereditary - antiplasmin deficiency
Acquired - drugs (tPA), disseminated intravascular coagulation
Describe the genetics of most bleeding disorders
Autosomal recessive
What is the treatment for abnormal haemostasis from failure of production/function
Replace missing factor/platelets
- Prophylactic
- Therapeutic
Stop drugs
What is the treatment for abnormal haemostasis from immune destruction
immunosuppression
What is the treatment for abnormal haemostasis from increased consumption
Treat cause
Replace as necessary
What can be used in factor replacement therapy
Plasma
Cryoprecipitate
Factor concentrates
Recombinant forms of FVIII and FIX
Describe plasma and cryoprecipitate for replacement therapy
Plasma = contains all coagulation factors
Cryoprecipitate = rich in fibrinogen, FVIII, VWF, FXIII
Describe factor concentrates
Concentrates available for all factors except factor V.
Prothrombin complex concentrates (PCCs) Factors II, VII, IX, X
What are some additional haemostat treatments
DDAVP
Tranexamic acid
Fibrin glue/spray
Describe desmopressin/DDAVP
a vasopressin derivative
Releases endogenous stores of VIII and - vWF, increasing levels 2-5x (VIII more than vWF)
Only useful in mild disorders (due to endogenous store release)
Describe transexamic acid
Inhibits fibrinolysis
Widely distributed – crosses placenta
Low concentration in breast milk
