Haemostasis and coagulopathy AB

Question 1

What is the mechanism of DDAVP in von Willebrand’s disease?

Answer 1

Increases factor VIII and von Willebrand’s factor coagulation activity by inducing release of vWF from endothelial cells

Question 2

What are the causes of intravascular haemolysis?

Answer 2

Mismatched blood transfusion
Red cell fragmentation: heart valves, HUS, TTP, DIC
G6PD deficiency
PNH
Cold autoimmune haemolytic anaemia

Question 3

What are the causes of extravascular haemolysis?

Answer 3

Haemoglobinopathies: thalassaemia, sickle cell anaemia
Hereditary spherocytosis
Warm autoimmune haemolytic anaemia

Question 4

Warfarin and skin necrosis - what factor deficiency predisposes to this?

Answer 4

Protein C deficiency

Question 5

In idiopathic thrombocytopenic purpura what are the autoantibodies most commonly directed at?

Answer 5

Glycoprotein IIb/IIIa complex

Question 6

Haemostasis testing - what is the role of the Ecarin time?

Answer 6

Ecarin time is useful to look to see whether a prolonged PT is due to Vit K deficiency or liver disease

Question 7

What are the differentials of elevated PT in isolation?

Answer 7

Factor VII deficiency

Early warfarin

Question 8

What are the differentials of elevated APTT in isolation?

Answer 8

Factor VIII, XI, XII or contact factor deficiency
Lupus anticoagulant (doesn't correct with mixing studies)

Question 9

What may cause elevated PT and APTT in isolation?

Answer 9

Vitamin K deficiency or Warfarin

Factor X, II or V deficiency

Multiple factor deficiency, e.g. liver disease

Question 10

What may cause elevated PT, APTT, TT with normal platelets?

Answer 10

Heparin or liver disease

Question 11

What are the coagulation abnormalities in DIC?

Answer 11

High PT, APTT, TT

Low platelet, low fibrinogen

Question 12

What may cause abnormal bleeding where the screening tests (PT, APTT, Fibrinogen, Platelets) are normal?

Answer 12

Platelet dysfunction
Factor XIII deficiency
Mild factor deficiency
Mild vWD

Question 13

What are the best tests for monitoring Dabigatran?

Answer 13

Ecarin CT

TT (too sensitive)

Question 14

What are the best measuring tests for anti-Xa inhibitors?

Answer 14

PT - more sensitive at high concentrations

Anti-Xa (quantitative)

Question 15

In which conditions are target cells seen in?

Answer 15

Decreased RBC volume:

• Haemoglobinopathies
• Iron deficiency

Increased RBC membrane:

• Liver disease
• Hereditary LCAT deficiency
• Post-splenectomy

Question 16

What is the differential diagnosis of spherocytosis?

Answer 16

Hereditary
Warm AIHA
Burns
Clostridium welchii sepsis
Wilson's disease
Phosphate deficiency

Question 17

What do you typically find on flow cytometry in hereditary spherocytosis?

Answer 17

Eosin-5 Maleimide