Bleeding disorders Flashcards by Adele Atkins

After injury, what 3 processes halt bleeding?

Vasoconstriction
Gap plugging by platelets
Coagulation cascade

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What 3 groups do disorders of haemostasis fall into?

Vascular defects
Platelet defects
Coagulation defects

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What pattern of bleeding do coagulation disorders cause?

Delayed bleeding

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What pattern of bleeding do vascular and platelet disorders cause?

Prolonged bleeding

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Give some congenital examples of vascular defects

Osler-weber-rendu syndrome

Connective tissue disease (Ehlers danlos)

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Give some acquired examples of vascular defects

Senile purpura
Infection - meningococcal, measles, dengue fever
Steroids
Scurvy (perifollicular haemorrhages) 
Henoch-schonlein purpura

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Give some examples of platelet disorders caused by decreased marrow production

Aplastic anaemia
Megaloblastic anaemia
Marrow infiltration (leukaemia and melanoma)
Marrow suppression (cytotoxic drugs and radiotherapy)

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Give some examples of platelet disorders caused by increased destruction

Immune thrombocytopenia (ITP)
SLE
CLL
Drugs - heparin
Virus
DIC
Thrombotic thrombocytopenia (TTP)
HUS
Sequestration (in hypersplenism)

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Give some platelet disorders caused by poorly functioning platelets

Myeloproliferative disease
NSAIDs
Increased urea

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Give some examples of congenital coagulation disorders

Haemophilia

Von Willebrand’s disease

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Give some examples of acquired coagulation disorders

Anticoagulants
Liver disease
DIC
Vitamin K defiency

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What is haemophilia A a deficiency of?

Factor 8

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How is haemophilia A inherited?

X-linked recessive condition, however 30% of cases arise from new mutations

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Describe the clinical presentation of haemophilia A

Depends on the severity
Often early in life or after surgery/trauma
Bleeds into joints - arthropathy
Bleeding into muscles - haematomas (increased pressure can lead to nerve palsies and compartment syndrome)

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How is haemophilia A diagnosed?

Increased APTT

Decreased factor 8 assay

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How is haemophilia A managed?

Minor bleeding - pressure and elevation
Major bleeding - desmopressin - raises factor 8 - raised by 50% may be sufficient
Severe bleeding - recombinant factor 8 to raise the levels by 100%

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What must be avoided in haemophilia A?

NSAIDs and IM injections

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What is haemophilia B otherwise known as?

Christmas disease

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How do you treat haemophilia B

Recombinant factor 9

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What is haemophilia B

Factor 9 deficiency

What is acquired haemophilia caused by?

Suddenly appearing autoantibodies to factor 8

What is the clinical presentation of acquired haemophilia?

Big mucosal bleeds in males and females

How is acquired haemophilia diagnosed?

Increased APTT
Increased factor 8 autoantibody
Factor 8 activity <50%

How do you treat acquired haemophilia

Steroids

Describe the bleeding disorder produced from liver disease

Complicated Decreased synthesis of clotting factors Decreased absorption of vitamin K Abnormalities of platelet function

What bleeding disorder does malnutrition lead to?

Decreased vit K | Decreased production of clotting factors 2,7,9,10

How do you treat bleeding due to decreased vit K absorption

Give 10mg IV vitK | In acute haemorrhage give FFP or human prothrombin complex

Describe the process of fibrinolysis

Plasminogen is converted to plasmin by tissue plasminogen activator. Plasmin can then cleave fibrin and other factors. t-PA and plasminogen both bind to fibrin and thus localise the fibrinolysis to the area of the clot

Name some fibrinolytic agents

Streptokinase Alteplase Tenecteplase Reteplase

Describe how streptokinase works

Streptococcal exotoxin that binds and activates plasminogen

What is the risk of fibrinolytic agents?

Haemorrhage

What is the risk of streptokinase?

Anaphylaxis on repeated doses

Describe the pathophysiology of immune thrombocytopenia (ITP)

Caused by antiplatelet autoantibodies

Describe the clinical presentation of immune thrombocytopenia (ITP)

Children - 2 weeks after infection, Sudden, self limiting purpura It may also be chronic in women - purpura (pressure areas), menorrhagia, epistaxis, bleeding

How is ITP diagnosed?

Increased megakaryocytes seen on marrow | Antiplatelet autoantibodies may be present

How is ITP managed?

No treatment if mild If symptomatic however or if platelets <20, give prednisolone. IV immunoglobulin may temporality rise platelets for surgery/pregnancy If relapses - splenectomy or be cell depletion with rituximab Eltromopag and romiplostim are alternative options for those with refractory disease

What is osler-weber-rendu otherwise known as?

Hereditary haemorrhagic telangiectasia

Describe hereditary haemorrhagic telangiectasia

``` Autosomal dominant Multiple telangiectasia on skin and mucous membranes Epistaxis Telangiectasias at multiple sites Visceral lesions - AVM First degree family relative with HHT ```

What is the most common inherited clotting disorder?

Von Willebrand

What does the prothrombin time test?

The extrinsic pathway | Factors 1,2,5,7,10

What causes the prothrombin time to be prolonged?

Warfarin Vit K deficiency Liver disease DIC

What does activated partial thromboplastin time (APTT) test?

The intrinsic pathway | Factors 1,2,5,8,9,10,11,12

What prolongs the APPT?

Heparin treatment Liver disease DIC Haemophilia

What is the thrombin time?

Time taken for thrombin to convert fibrinogen to fibrin

What prolongs the thrombin time

Heparin treatment DIC Dysfibrinogenaemia

What are D-dimers?

Fibrin degradation products, released from cross linked fibrin during fibrinolysis

When are D-dimers released?

DIC VTE/PE Inflammation - infection/malignancy

What questions should you ask in a pre-op assessment to establish bleeding risk?

Previous history of any excessive bleeding Drug history - anything which may affect haemostasis PMH - lupus or liver disease