M103 T2 L6 Flashcards

1
Q

What are the causes of bleeding?

A

Vascular disorders
Platelet disorders
Defective coagulation

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2
Q

What are the patterns of bleeding for vascular and coagulation disorders?

A

vascular - bleeding into mucous membranes and skin

coagulation - bleeding into joints and soft tissues

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3
Q

What types of vascular bleeding is there?

A

Inherited (rare) - haemophilia a & b
Acquired (common)
coagulation cascade defect

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4
Q

What is the normal range of platelets? In what range is thrombocytopenia?

A

150-400 x 10^9/L

thrombo - less than the lower range

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5
Q

What are the symptoms of thrombocytopenia?

A

Epistaxis
GI bleeds
menorrhagia
bruising

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6
Q

At what platelet level will symptomatic bleeding occur?

A

when the platelet level falls below 10 x 10^9/L

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7
Q

What are the common aquired causes of thrombocytopenia?

A

ITP
drug-related
DIC

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8
Q

How is immune thrombocytopenia treated?

A

steroids and/or intravenous immunoglobulins
thromboietin agonists
immunosuppression
splenectomy

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9
Q

What are the symptoms of immune thrombocytopenia and what are they caused by?

A

affected individuals can develop red or purple spots on the skin caused by bleeding just under the skin’s surface

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10
Q

What are the acquired causes of disorders of platelet function?

A

iatrogenic illness

drs prescribing aspirin, NSAIDs that are very effective anti-platelet agents

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11
Q

What is prothrombinase made up of?

A

factor 10
factor 5
calcium
pplpds (surface of the platelets)

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12
Q

Where does the coagulation happen?

A

at the surface of the membrane of the platelet - very convoluted

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13
Q

What are the clinical features of Haemophilia A & B?

A

Spontaneous bleeding into joints and muscle
Unexpected post-operative bleeding
Chronic debilitating joint disease
Family history in majority of cases

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14
Q

What are consequent conditions due to haemophilia?

A

major haematoma
haemarthrosis
chronic joint deformity
intra-cranial bleed

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15
Q

Describe the genetics of a haemophiliac family

A

mother carrier - sons will have haemophilia, daughters will be carriers
positive father - sons will be normal, daughters will be carriers

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16
Q

What are the tests of coagulation?

A

APTT
PT
TT
Fibrinogen level
Clotting factor assays (normal level 100%)
D-dimers - breakdown products of fibrin clot

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17
Q

Which tests are done to diagnose haemophilia?

A

Prolonged APTT
Normal PT
Low factor VIII or IX levels
<1% = severe; 1-5% = moderate; >5% = mild haemophilia

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18
Q

When measuring factor VIII or IX levels, what are the percentages for the three levels of severity of haemophilia?

A
<1% = severe
1-5% = moderate
>5% = mild haemophilia
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19
Q

Why were high proportions of haemophiliac patients getting AIDS?

A

the treatments of these patients with infected with the clotting factors of infected blood products

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20
Q

What is the main treatment for severe haemophilia?

A

prophylactic doses of their missing clotting factors once or twice a week to prevent bleeding

21
Q

Describe the von Villebrand disease genetically

A

Autosomal dominant

22
Q

What are the effects of von Villebrand disease?

A

Mucocutaneous bleeds
nosebleeds
menorrhagia

23
Q

What tests are used to diagnose von Villebrand disease?

A
Prolonged APTT
Normal PT
Low vWF antigen level and/or vWF function (von Villebrand factor)
Low factor VIII level
Prolonged bleeding time
Defective platelet function
24
Q

What factors does Prolonged APTT test for to take a measure of how long it takes for the placements clot?

A

tests factors VIII, IX, XI, XII in the intrinsic pathway

25
Q

How is von Villebrand disease treated?

A

desmopressin (DDAVP)
anti-fibrinolytics
plasma products

26
Q

How does desmopressin (DDAVP) work?

A

stimulates the release of VWF from the endothelial cells where it is stored

27
Q

What are the acquired disorders of coagulation / haemophilia?

A

Liver disease
Vitamin K deficiency
Disseminated intravascular coagulation (DIC)

28
Q

How does liver disease lead to haemophilia?

A

the liver is the site of synthesis for clotting factors

Deficient synthesis in the liver because of living disease will lead to impaired platelet function and fibrinolysis

29
Q

Under what circumstances can infants develop acquired haemophilia?

A

if they don’t receive vitamin K at birth

if they have jaundrice, malabsorption

30
Q

How does Disseminated intravascular coagulation (DIC) lead to haemophilia?

A

Release of pro-coagulant material into circulation
Results in consumption of clotting factors
Causes both bleeding and thrombosis to occur

31
Q

What age groups does Meningococcal DIC affect?

A

mainly in children or sometimes adults

32
Q

What happens when the clotting cascade is overactivated in Meningococcal DIC?

A

leads to disseminate intravenous coagulation

33
Q

What is the cause of thrombosis or bleeding risk in Meningococcal DIC?

A

when all the clotting factors are used up = acquired coagulopathy

34
Q

What do blood tests for Meningococcal DIC show?

A

prolongation of PT, APTT, TT
low fibrinogen and low platelets - everything gets used up due to the septosemic process
raised D-dimers or FDPs

35
Q

What are the anticoagulant drugs that are iatrogenic causes of Meningococcal DIC when overprescribed?

A

Heparin c valves
DOACs
Direct thombin inhibitors (dabigatran, argatroban)
Factor Xa inhibitors (rivaroxaban, apixaban)

36
Q

What condition do patients on warfarin usually get?

A

intracranial bleeds

GI bleeds

37
Q

How are intracranial and GI bleeds caused by warfarin treated?

A

urgent reversal of the drug administeration

38
Q

How does warfarin work?

A

by competing with / inhibating vitamin K

39
Q

What is vitamin K required for?

A

the gamma-carboxylation of factors II, VII, IX, X

40
Q

What groups of people have a deficiency in vitamin K and why?

A

jaundice people - need bile to absorb vitamin k - as vitamin K is fat soluble
babies born prematurely

41
Q

What is done to try and prevent babies from being vitamin K deficient and why?

A

injected with vit K a few hours after birth

prevents complications - haemorrhagic disease of the newborn

42
Q

What is the difference between PTT and aPTT?

A

THEY ARE THE SAME THING - both used to test for the same functions
BUT - in activated PTT, an activator is used that speeds up the clotting time and results in a narrower reference range

43
Q

What are the factors of the intrinsic pathway?

A

VIII, IX, XI, XII

44
Q

What does an increased PTT in a patient with a bleeding disorder indicate?

A

that a clotting factor may be missing or defective

45
Q

What are PT blood tests used to test for?

A

the presence of bleeding problems

whether medicines that prevent blood clots are working

46
Q

What is the difference between PTT and PT blood tests?

A

PT - EXtrinsic system

PTT - INtrinsic system

47
Q

What is the normal PT value?

A

11 to 16 secs

48
Q

What bacteria is responsible for septicemia?

A

meningococcaemia

49
Q

What is sepsis caused by?

A

when a patient has septicemia, sometimes the body has an immune reaction to it
it releases lots of chemicals into the blood, triggering widespread inflammation that can lead to organ damage