Secondary haemostasis failure

Question 1

what is secodnary haemostasis failure?

Answer 1

-failure of fibrin clot formation

Question 2

causes of secondary haemostasis failure?

Answer 2

clotting factor deficiency: either single or multiple

Multiple clotting factor deficiencies (acquired):
o liver failure (as all coagulation factors are synthesised in liver)
o vitamin K deficiency
o warfarin therapy
o disseminated intravascular coagulation

Single clotting factor deficiency :
o generally hereditary e.g. haemophilia A and B

Question 3

causes of multiple clotting factor deficiency?

Answer 3

-Liver failure
- vitamin K deficiency
-warfarin therapy
-disseminated intravascular coagulation (DIC)

Liver failure (as all coagulation factors are synthesised in liver)
-Vitamin K deficiency (as this carboxylases the clotting factors and so makes them negative which allows them to bind to positively charged calcium on negatively charged platelet)
-Warfarin therapy (warfarin blocks Vit K step in clotting factors)
-Disseminated intravascular coagulation

Question 4

causes of single clotting factor deficiency?

Answer 4

-usually hereditary e.g. Haemophilia A or B

Question 5

what does haemophilia B interact with?

Answer 5

Haemophilia B
-interacts with clotting factor IX

Question 6

what does haemophilia A interact with?

Answer 6

Haemophilia A- Ate- 8
-interacts with clotting factor VIII

Question 7

APPT and PT of single vs multiple clotting factor deficiency?

Answer 7

Single:
APPT- prolonged
PT- normal
(unless only clotting factor VII involved which would cause prolongation of PT and normal APPT)

Multiple
APPT- prolonged
PT- prolonged

Question 8

would Vitamin K deficiency cause a single or multiple clotting factor deficiency and why?

Answer 8

Multiple

Vitamin K is involved in carboxylation of clotting factors causing them to be negatively charged, allowing them to bind to the positively charged calcium ions on the platelet membrane

Question 9

Vitamin K dependant clotting factors?

Answer 9

Vit K dependant clotting factors: II, VI, IX, X (2, 7, 9, 10)

Question 10

where is Vit K absorbed?

Answer 10

absorbed in upper intestine

Question 11

what is required for Vit K absorption?

Answer 11

Requires a bile source
(so will not be absorbed in obstructive jaundice)

Question 12

sources of Vit K?

Answer 12

-Diet (leafy greens)
-Bacterial synthesis

Question 13

causes of vitamin K deficiency?

Answer 13

-Malabsorption e.g. Chrons
-Diet (lack of leafy greens)
-Obstructive jaundice (require bile for absorption)
-Warfarin (Vit K antagonist)
-Haemorrhagic disease of newborn

Question 14

What is disseminated intravascular coagulation (DIC)?

Answer 14

A multiple clotting factor deficiency cause of secondary haemastasis

-Excessive and inappropriate activation of the haemostatic system (primary, secondary and fibrinolysis)

-this causes both microvascular thrombus formation (which can lead to end organ failure) and clotting factor consumption

Question 15

Causes of disseminated intravascular coagulation (DIC)?

Answer 15

-Sepsis
-Obstetric emergencies e.g. placental abruption
-Malignancy (usually slower + more chronic presentation)
-Hypovolaemic shock
-Road Traffic Accidents

Question 16

Presentation DIC?

Answer 16

the underlying issue
e.g. sepsis, RTA, hypovolaemic shock, obstetrics emergency, malignancy

AND

-Bruising
-Purpura
-Generalised bleeding

Question 17

Investigaitons of DIC?

Answer 17

-Raised d-dimer D dimer is a byproduct of fibrin degredation
-Decreased fibrinogen (also shown as increased Thrombin time)
-Thrombocytopenia
-Increased PT
-increased APTT

Question 18

how to tell the difference between DIC and liver failure as a cause of failure of secondary haemastasis if both have increased PT and increased APTT?

Answer 18

Both:
-increased PT
-increased APTT

DIC- will have raised D dimers, decreased fibrinogen (increased thrombin time)

Liver failure- decreased albumin

Question 19

treatment- DIC?

Answer 19

treat underlying cause + contact senior

-platelet transfusion
-plasma transfusion
-fibrinogen replacement

Question 20

what is an example of a hereditary single clotting factor deficiency cause of secondary haemostasis failure?

Answer 20

-Haemophilia A
-Haemophilia B

Question 21

what is Haemophilia?

Answer 21

An X linked hereditary disorder in which abnormally prolonged or spontaneous bleeding occurs

Question 22

what is the inheritance of haemophilia and who is more likely to get it ?

Answer 22

X linked
-Men only really affected
-Women are carriers

Question 23

What clotting factors do Haemophilia A and B affect?

Answer 23

Haemophilia A= factor 8 deficiency (5x more common)
8=8 ate= A

Haemophilia B= factor 9 deficiency

Question 24

does haemophilia affect primary haemostasis?

Answer 24

No- haemophilia only affects secondary haemostasis (and so tends to affect medium to large vessels)

Question 25

presentation haemophilia?

Answer 25

Most present in neonates or early childhood:
* Intracranial haemorrhage
* Haematomas
* Cord bleeding

Ankle and knee are most commonly affected
-Recurrent hemarthroses (bleeding into joints)
-Recurrent soft tissue bleeds (bruising in toddlers)
-Prolonged bleeding after dental extraction, surgery and invasive procedures

Abnormal bleeding can occur in: Gums, Gastrointestinal tract, Urinary tract causing haematuria, Retroperitoneal space, Intracranial, Following procedures

Question 26

presentation of APTT or PT in haemophilia?

Answer 26

PT= normal
APTT= prolonged

Question 27

Treatment of haemophilia?

Answer 27

Affected clotting factors (8 or 9) can be replaced by IV infusions – prophylactically or in response to bleeding

(Complication – formation of antibodies against the clotting factor resulting in treatment becoming ineffective )

Question 28

treatment acute episode of haemophilia?

Answer 28

-Infusions of affected factor (8 or 9)
-Desmopressin to stimulate release of VWF
-Antifibrinolytics e.g. tranexamic acid