CP37 - Heritable Bleeding Disorders Flashcards
when is tissue factor expressed
TF is expressed when damages to cells are done and will be presented on the surface of blood vessels
what activate factor 7 in blood ?
tissue factor
when does common pathway start
when factor 1 0is activated
when will intrinsic pathway of coagulation pathway start?
when blood come into contact with foreign surfaces
which factors is activated first when blood come into contact with foreign objects
factor 12
what does coagulation screen tests consist of ?
prothrombin time, activated partial thromboplastin time, thrombin clotting time or euglobulin lysis time
how does the prothrombin time test work?
time taken for clot to appear after TF and Ca+ are added to the sample - looking at the extrinsic pathway
how does the activated partial thromboplastin time work?
time taken for fibrin clot to appear after the calcium-phospholipid mixture is added. - looking at the intrinsic pathway
what are some of the agents present for anti-coagulant?
Protein C, protein S, anti-thrombin III, fibrinolytic system
which enzyme breaks down fibrin
plasmin
where are the common places for haemorrhage to occur for patient who has platelet/bleeding disorder
mucosal and skin
where are the common places for haemorrhage to occur for patient who has coagulation defect
deep muscle & joint bleeds, bleeding more following trauma
what is an example for abnormal platelet fucntion
aspirin
what is an example for abnormal vessels wall
scurvy - Vit C important for production of collagen which is an important component of cell wall
what is an example for abnormal interaction between platelets & vessel wall
von Willebrand disease - von Willebrand factors - act like glue
which type of von Willerbrand disease is the most common
type 1
what is the problem in type 1 von Willerbrand disease
low production of normal VWF.
what is the problem in type 2 von Willerbrand disease
normal amount of VWF but abnormal quality
what is the problem in type 3 von Willerbrand disease
almost absent of VWF
which coagulating factor does VWF carry?
factor 8
what can reduce level of VWF cause
factor 8 deficiency
what is the mechanism of inheritance for von Willerbrand disease?
autosomal dominant inheritance
what is the pattern of bleeding for von Willerbrand diseaese?
mucocutanous bleeding including menorrhagia
which blood group have a lower VWF?
group O
what are the treatment of von willebrand disease
tranexamic acid - antifibrinolytics
DDAVP (desompressin) - release VWF into plasma temporality for type 1 vWD
which coagulation factor is deficient in haemophilia A
Factor 8
which coagulation factor is deficient in haemophilia B
factor 9
what is the mode of inheritance for haemophilia
sex linked recessive
which test is prolonged for patients with haemophilia A & B
APTT - affect intrinsic pathway
can haemophilia be sporadic?
yes - about 30%
what is the pattern of bleeding for haemophilia ?
Spontaneous/Post traumatic Joint Bleeding = Haemarthrosis Muscle Haemorrhage Soft Tissue Life Threatening Bleeding – tissue surrounding the airway
what are the treatment for haemophilia
replacement of clotting protein - on demand/prophylaxis
DDAVP
antifibrinolytic agents
vaccination vs Hep A and B
what are some complication for treatment of haemophilia
transfusion transmitted infection, inhibitor development - enzyme against factor 8 or 9
