Bleeding Disorders

Question 1

Describe disseminated intravascular coagulation and its causes

Answer 1

It is an acquired disease which causes microthrombi due to activation of the coag cascade and bleeding due to exhaustion of the coag cascade.
Caused by sepsis, malignancy, massive haemorrhage, severe trauma and pregnancy complications (pre-eclampsia, placental abruption, amniotic fluid embolism).

Question 2

What are the laboratory investigations for DIC?

Answer 2

• Coagulation PT, APTT, Fibrinogen
• D-dimer
• FBC, Platelets and blood film which shows RBC fragments (Due to fibrin which lays down in the vessel and cuts the RBCs as they travel past)

Question 3

What is the treatment for DIC?

Answer 3

Fresh frozen plasma +/- platelets if bleeding/high risk for bleeding.

Question 4

How do you treat a major bleed for a patient in warfarin

Answer 4

• Stop warfarin,
• Give 5mg IV vitamin K,
• intravenous factor concentrate (prothrombin complex concentrate)

Question 5

What can you do if there is a prolonged APTT?

Answer 5

50:50 dilution. mix patient plasma with normal plasma. If the patient has a factor deficiency then there will be full correction. If the patient has an inhibitor then there will only be partial correction

Question 6

What is lupus anticogulant?

Answer 6

Phospholipid dependant antibody which interferes with phospholipid dependant tests eg, APTT. If it persists then it may be associated with a prothrombotic state

Question 7

How can you test for lupus anticoagulant?

Answer 7

• APTT is often prolonged and only partially corrected with an APTT 50:50 dilution.
• DRVVT ration prolonged and it corrected with excess phospholipids

Question 8

Explain acquired thrombophilia

Answer 8

• It is an antiphospholipid syndrome caused by the presence of antiphospholipid antibodies. This could be lupus anticoagulant, anti cardiolipin antibodies or beta-2 glycoprotein-1 antibodies.
  They disrupt annexin V sheild which expose excess phospholipid. Can cause venous/arterial thrombosis or recurrent miscarriages.

Question 9

Describe features of haemophilia A

Answer 9

• An x-linked deficiency of factor VIII.
• Results in prolonged APTT

Question 10

What is the treatment for coagulation factor deficiencies

Answer 10

• Education,
• Desmopressin (increases endogenous release of factor 8)
• Replacement therapy (FFP, plasma derived factor concentrate and recombinant produced factor concentrate)

Question 11

What is the role of Von Williebrand factor?

Answer 11

1. Facilitates platelet adhesion and aggregation in primary haemostasis,
   2.Binds to factor VIII and prolongs its half life in plasma

Question 12

Describe features of Von Williebrand disease

Answer 12

• Autosomal dominant condition with variable penetrance.
• Leads to muscosal type bleeding patteern
• Will cause reduced VWF, and possibly reduced platelet aggregation and reduced factor VIII

Question 13

What are the different classes of Von Williebrand disease?

Answer 13

Type 1 - Partial quantitative deficiency
Type 2 - Functional deficiency
Type 3 - Almost complete deficiency of VWF

Question 14

Name some different severe inherited platelet disorders

Answer 14

• Glansmanns Thrombasthenia (normal platelet count bit absent/defective GP IIb/IIIa)
  -Bernard Soulier Syndrome (Absent/defective GP Ib/V/IX and macrothrombocytopenia)
• Both are rare autosomal recessive disorders with mucosal type bleeding pattern

Inherited platelet disorders are BullShit and Great Threats

Question 15

How can you treat bleeding in a person with an inherited platelet disorder?

Answer 15

1. Pressure to wounds
2. Tranexamic acid/desmopressin
3. Platelet transfusion
4. Recombinant factor VIIa

Question 16

Describe features of inherited thrombophilia

Answer 16

• Deficiencies in natural anticoagulants eg, antithrombin, protein C and protein S.
• Genetic mutations include factor V Leiden (resistance to APC) and prothrombin gene mutation which results in increased prothrombin

Question 17

Explain features of coagulopathy in liver disease

Answer 17

• Poor coagulation factor synthesis in the liver,
• vitamin K deficiency
• Poor clearance of activated coag factors
• May present with DIC, hypersplenism and reduce thrombopoietin synthesis