Coagulation

Question 1

Commonest inherited bleeding disorder ?

Answer 1

von Willebrand’s Disease (vWD)

Question 2

In Von willebrand disease severity of the disease can vary within a family ( T or F )

Answer 2

True
Variable penetrance – FHx might not be helpful especially in mild disease

Extra - Usually, the inheritance is autosomal dominant. The severity of the bleeding is highly variable

Question 3

Clinical presentation of Von willebrand disease

Answer 3

Typically, there is mucous membrane bleeding (e.g. epistaxes, menorrhagia),
excessive blood loss from superficial cuts and abrasions, operative and post‐traumatic haemorrhage.

The severity is variable in the different types.
Haemarthroses and muscle haematomas are rare.

Question 4

Role of vWF in Coagulation ?

Answer 4

Important in both adhesion and aggregation of platelets.

FVIII is bound to vWF in plasma – prevent FVIII from early clearance.
Therefore Fviii levels my be reduced in vWD

Question 5

Confirmatory investigations for von willebrand’s disease

Answer 5

Platelet function / aggregation tests
Ristocetin cofactor assay –
measures the ability of circulating von Willebrand factor
to cause platelet aggregation
von Willebrand factor level (antigen assay - ELIZA)
vWF Multimer analysis – diagnose the subtype

Question 6

Treatment option for von-williebraved disease

Answer 6

desamino-8-arginine vasopressin (DDAVP) (Desmopressin)

raise the levels of von Willebrand factor level
reduce the tendency toward bleeding

Some types of vWD do not respond to DDAVP

Question 6

Treatment option for von-williebraved disease

Answer 6

desamino-8-arginine vasopressin (DDAVP) (Desmopressin)

raise the levels of von Willebrand factor level
reduce the tendency toward bleeding

Some types of vWD do not respond to DDAVP

Question 7

Thing that can increase vWF and factor viii levels in a person ?

Answer 7

Environmental intluences
(1 ) adrenalin release - strenuous exercise or stress
(2) inflammatory conditions
(3) severe liver disease
(4) high levels of thyroid hormones - hyperthyroidism
(5) high levels of estrogen and progesterone - pregnancy

Blood group
A,B ) O (ADAMTS-13 levels higher in group O)

Age
Neonates, < 6 months

Race
Black Africans