Bleeding Disorders

Question 1

what is primary haemostasis

Answer 1

formation of a platelet plug

Question 2

what is secondary haemostasis

Answer 2

formation of a fibrin clot

Question 3

failure of what aspects of haemostasis usually cause bleeding disorders

Answer 3

primary and secondary haemostasis

problems with fibrinolysis and anticoag defences less likely

Question 4

what can cause platelet plug formation failure

Answer 4

vascular (collagen loss, hereditary, acquired)
platelets:
- reduced number (thrombocytopenia- marrow problem, ITP)
-reduced function (drugs e.g. aspirin, anti-inflammatories)
von willebrand factor (hereditary deficiency)

Question 5

what is thrombocytopenia

Answer 5

reduced platelets

Question 6

what inheritance is VWF deficiency

Answer 6

AD

affects men and women equally

Question 7

why does collagen loss cause failure of primary haemostasis

Answer 7

vessel less efficient, more leaky

Question 8

what hereditary conditions can cause vascular abnormalities

Answer 8

hereditary deficiencies in collagen: marfans, disorders of hyperflexibilty

Question 9

what are the acquired causes of vascular abnormalities causing failure of primary haemostasis

Answer 9

vasculitis: inflammation of vessel, makes it more leaky
e. g. HSP

scurvy (vit c needed to make collagen)

age- senile purpura

Question 10

what are the features of henoch schonlein purpura

Answer 10

seen in children
triggered by viral infection
Antibodies to virus stick to vessel wall and make them leaky
mucosal bleeding- purpura on lower limbs
supportive Tx, usually self limiting, occasionally need transfusion

Question 11

where is purpura most commonly seen

Answer 11

on lower limbs (gravity effect)
can be seen on chest if have cough
fundi on ophthalmoscope
blood blisters in mouth

Question 12

is hereditary or acquired thombocytopenia more common

Answer 12

acquired

Question 13

what are the causes of acquired thrombocytopenia

Answer 13

reduced production:
-marrow problem (viral infection, aplastic anaemia, malignancy (mets or blood), chemo, alcohol) (will also have anaemia and low wbc)

increased destruction (most common cause)

• usually autoimmune (ITP)
• coagulopathy (DIC)
• hyperplenism

Question 14

what is the normal lifespan of a platelet

Answer 14

7 days 
(in increase peripheral destruction will last couple of hours)

Question 15

what is seen on blood film in increased peripheral destruction of platelets

Answer 15

large platelets (immature forms)

Question 16

what is usually the Tx for thrombocytopenia caused by increased peripheral destruction

Answer 16

(treat cause)
usually self limiting problem
Tx in children is to observe
Tx can involve steroids in adults

Question 17

what causes DIC

Answer 17

(disseminated intravascular coagulation)
trigger (trauma, RTA, sepsis, incompatible transfusion, cancer) that results in tissue damage activates both primary and secondary haemostasis
this uses up clotting factors (prolonged PT and APTT)
blood clots block small blood vessels causing hypoxia which triggers more clots
body recognises this and activated fibrinolysis but this only causes more tissue damage and destroys clotting factors

Question 18

how does hypersplenism affect platelets

Answer 18

caused by e.g. liver disease, cancer
blood cant get into liver due to cirrhosis and spleen engorges
this then increases transit time of blood through spleen, increasing destruction of platelets

Question 19

what are the causes of platelet functional defects

Answer 19

hereditary (VWF def)

acquired

• drugs; aspirin, NSAIDs
• renal failure

Question 20

are NSAIDs antiplatelets or anticoagulants

Answer 20

anti platelets

Question 21

why does renal failure affect platelets function

Answer 21

due to build up of urea and in blood

Question 22

what are the causes of VWF deficiency

Answer 22

acquired (autoimmune, antibody to VWF (rare))

hereditary (common, AD, variable severity- generally mild)

Question 23

what does hereditary VWF def tend to cause

Answer 23

primary haemostatic problems: nose bleeds, gum bleeds, menorrhagia, bleeding after surgery/ dental extraction
(all these mucosal bleeds)

Question 24

what is the commonest cause of primary haemostatic failure

Answer 24

thrombocytopenia

this is usually acquiredL marrow failure (pancytopenia), peripheral destruction (ITP)

Question 25

what is the treatment for thrombocytopenia

Answer 25

transfusion (unless caused by increased peripheral destruction)

Question 26

what is ITP

Answer 26

immune thrombocytopneic purpura autoimmune disorder with increased platelet destruction and reduced prodcution (can be idiopathic or due to another AI condition, viral infections, H. pylori infections, medications and lymphproliferative disorders) can occur in adults and children

Question 27

what can cause a failure in fibrin clot formation

Answer 27

multiple clotting deficiencies (usually acquired e.g. DIC (destroyed), liver failure (not produced)) single clotting factor deficiency (generally hereditary - Heamophilia A and B)

Question 28

what can cause multiple clotting factor deficiencies

Answer 28

``` liver failure vit K deficiency/ warfarin therapy complex coagulaopathy (DIC) ```

Question 29

how do you measure liver production

Answer 29

albumin

Question 30

what is the role of vit K

Answer 30

allow carboxylase to make clotting factors negative so they can stick to +ve platelets

Question 31

WHAT CLOTTING FACTORS ARE MADE WITH VIT K IN EXAMS LEARN THIS

Answer 31

2,7,9 and 10

Question 32

what antagonises vit k

Answer 32

warfarin

Question 33

what clotting tests are affected in a multiple factor deficiency

Answer 33

both PT and APTT increased

Question 34

where are all coagluation factors synthesised

Answer 34

in hepatocytes (reduced in liver failure)

Question 35

what clotting factors are carboxylated by vit K IN EXAMS

Answer 35

2,7,9,10

Question 36

what are the sources of vit K

Answer 36

``` diet intestinal synthesis (made by bacterial in bowl) ```

Question 37

where is vit K absorbed and what is needed

Answer 37

in upper intestine | need bile salts to absorb it

Question 38

why do babies get haemorrhagic disease of the new born

Answer 38

as deficient in vit k- none in breast milk and very little bowel bacterial to make any

Question 39

what are all babies given at birth

Answer 39

vit k injection

Question 40

what can cause decreased vit k absorption

Answer 40

``` bowel disease obstructive jaundice (gallstones) ```

Question 41

what are the causes of vit k deficiency

Answer 41

``` poor diet malabsorption obstructive jaundice vit K antagonists (warfarin) haemorrhagic disease of the new born ```

Question 42

what are the dietary sources of vit K

Answer 42

leafy green veg

Question 43

what causes the clinical features of DIC

Answer 43

excessive and inappropriate activation of haemostasis (primary, secondary and fibrinolysis) microvascular thrombus formation = end organ failure clotting factor and platelet consumption= bruising, purpura and generalised bleeding

Question 44

what are the screening tests for fibrin clot formation

Answer 44

if CF deficiency (multiple- DIC, liver disease, warfarin) then PT and APTT will both be affected fibrin degredation products (e.g. D-dimers)

Question 45

what clotting factors are affected by warfarin

Answer 45

2,7,9 and 10

Question 46

which clotting test is most sensitive

Answer 46

PT and measures CF & which has the shortest half life

Question 47

what can cause DIC

Answer 47

sepsis (tissue damage due to infection or later shock) obstetric emergencies (placenta v rich in phospholipid and tissue factor, things like abruption can cause placenta to die causing coagulation) cancer hypovolaemic shock

Question 48

what is the treatment of DIC

Answer 48

treat underlying cause (sepsis 6, fluids) replacement therapy: -platelet transfusions -plasma transfusions (TTP to replace clotting factors) -fibrinogen replacement (cryoprecipitate)

Question 49

what is haemophilia

Answer 49

X linked hereditary disorder that causes loss of amplification (CF 8 and 9) process in haemostasis abnormally prolonged bleeding recurs episodically at one/ few sites on each occasions

Question 50

does haemophilia affect males or females

Answer 50

males (females can be carriers)

Question 51

what are the types of haemophilia

Answer 51

A- factor 8 deficiency (most common) B- factor 9 deficiency

Question 52

how does haemophilia present

Answer 52

no abnormality of primary haemostasis (fine with small cuts) mucosal bleeding less common bleeding will be from medium to large vessels get target joints- bleeding into ankle, knee and elbow joints causes synovitis which then causes neovascularisation in synovium which are friable and also bleed

Question 53

what are the severities of haemophilia

Answer 53

mild (>5% CF, only issues after trauma) mod 2-5% CF severe <2% CF

Question 54

what screening tests for haemophilias

Answer 54

APTT will be affected (v prolonged) | looks at CF 8 and 9

Question 55

what are the clinical features of haemophilia

Answer 55

recurrent haemarthoses recurrent soft tissue bleeds (bruising in toddlers) prolonged bleeding after dental extractions/ invasive procedures (usually FHx, 1/3rd new mutation)

Question 56

what Tx for haemophilia

Answer 56

prophylactic CF injections every 2nd day | may need joint replacements