Bleeding disorders Flashcards
what are causes of bleeding
Vascular disorders
Platelet disorders
Defective coagulation
what are types of platelet disorders
Thrombocytopenia
Defective function
what are types of defective coagulation
Inherited
Acquired
what pattern of bleeding is caused by vascular and platelet disorders
Bleeding into mucous membranes and skin
what pattern of bleeding is caused by coagulation disorders
Bleeding into joints and soft tissues
what are inherited issues with vessel walls
Hereditary haemorrhagic telangiectasia
Ehlers-Danlos syndrome
what are acquired issues with vessel walls
Scurvy, steroids, senile
what is Hereditary haemorrhagic telangiectasia
Also known as Osler-Weber-Rendu
haemorrhage spots on tongue lips (mucous membranes?)
what is the normal range of platelets
150-400 x 109/L
what is the range of platelets to thrombocytopenia
<150
what are symptoms when platelets are less than 10
Epistaxis, GI bleeds, menorrhagia, bruising
what are other causes of thrombocytopenia
Inherited causes (rare) or Acquired causes (common) eg: ITP, drug-related, DIC
what is ITP
immune thrombocytopenia
What are treatment options if bleeding or platelets <20
steroids and/or intravenous immunoglobulins
thromboietin agonists e.g., romiplostim
immunosuppression e.g. rituximab
splenectomy
what is a key sign of disorders of platelet function
Platelet count – typically normal
what are types of disorders of platelet function
Inherited, many rare diagnoses,
e.g., Glanzmann’s thrombasthenia
Acquired, Drugs – much more common
e.g., Aspirin, NSAIDs
what causes disorders of coagulation
Due to a defect in the coagulation cascade
what are types of coagulation disorders
Inherited causes (rare)
Acquired causes (common)
what clotting factors are TF, Prothrombin, Thrombin, Fibrinogen
TF III Prothrombin II Thrombin IIa Fibrinogen I Prothrombinase X,V,Ca2+,PL
What are tests of coagulation
APTT
PT
TT
What is APTT
activated partial thromboplastin time to assesses the intrinsic pathway
What is PT
prothrombin time to assesses the extrinsic pathway
what is TT
thrombin time to assesses terminal common pathway
what are other tests of coagulation
Fibrinogen level
Clotting factor assays (normal level 100%)
Bleeding time (time to stop bleeding) - no longer done
D-dimers = breakdown products of fibrin clot
what are the types of haemophilia
Haemophilia A – deficiency of factor VIII
Haemophilia B – deficiency of factor IX
(also known as Christmas disease)
what are the clinical features of haemophilia
Spontaneous bleeding into joints and muscle
Unexpected post-operative bleeding
Chronic debilitating joint disease
Family history in majority of cases (X linked)
how is haemophilia diagnosed
Prolonged APTT
tests factors VIII, IX, XI, XII in the intrinsic pathway
Normal PT
tests factors II, V, VII, X in the extrinsic pathway
Low factor VIII or IX levels
what is considered low for factor VIII or IX in haemophilia
<1% = severe; 1-5% = moderate; >5% = mild haemophilia
what are historic treatments for haemophilia
Historic treatments – fractionated human plasma but risk of HIV and Hepatitis C infection (and risk of vCJD)
what are current treatments for haemophilia
Current treatment – infusions of recombinant factor VIII or factor IX to 50-100% of normal
Prophylactic treatment has revolutionised management of haemophilia patients
what is von willebrand disease
Autosomal dominant
vWD = deficiency of vWF and FVIII in plasma
Mucocutaneous bleeds, nosebleeds, menorrhagia
what is von willebrand factor
large multimeric protein that carries factor VIII in the blood
vWF also binds platelets to endothelial collagen
what are tests for diagnosing vWD
Prolonged APTT Normal PT Low vWF antigen level and/or vWF function Low factor VIII level Prolonged bleeding time Defective platelet function
how can vWD be treated
Treatment with desmopressin (DDAVP), anti-fibrinolytics and plasma products
what does DDVAP do for vWD
DDAVP stimulates release of vWF from Weibel-Palade storage bodies from endothelial cells
what are acquired disorders for coagulation
These are non-inherited causes of increased bleeding
Liver disease, bit K deficiency, disseminated intravascular coagulation (DIC)
How is liver disease an acquired disorder of coagulation
Deficient synthesis of clotting proteins
Impaired platelet function and fibrinolysis
How is vit K deficiency an acquired disorder of coagulation
Infants who do not receive vitamin K at birth
Malabsorption due to jaundice
How is DIC an acquired disorder of coagulation
Release of pro-coagulant material into circulation
Results in consumption of clotting factors
Causes both bleeding and thrombosis to occur
What are anti coagulant drugs
Heparin – used to treat MIs, PEs, DVTs
Warfarin – used to treat PEs, DVTs, AF, prosthetic valves
DOACs = direct oral anti-coagulants
Direct thombin inhibitors (dabigatran, argatroban)
Factor Xa inhibitors (rivaroxaban, apixaban)
what causes a vitamin k deficiency
Malabsorption of vitamin K
Biliary obstruction (jaundice)
Haemorrhagic disease of the newborn (give 1mg at birth)
what is vitamin k used for
Vitamin K is required for gamma-carboxylation of factors II, VII, IX, X
Inhibited by warfarin (monitored using the INR)
what is Haemoarthritis
bleeding in the joints
