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IMS- Strand 4 > The Coagulation Panel > Flashcards

The Coagulation Panel Flashcards

1
Q

What is Haemostasis?

A

Process to fix a break in blood vessel wall

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2
Q

How are coagulation factors involved in secondary haemostasis measured?

A
  • Blood contained in citrate tube
  • Spin blood, set off the coagulation cascade
  • Visually look for a clot
  • Automated system detects light penetration (as fibrinogen becomes fibrin and strands start to crosslink the mixture gets cloudy and machine detects this)
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3
Q

What is PT?

A

Prothrombin time measured in seconds

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4
Q

What is APTT?

A

activated partial thromboplastin time measured in seconds

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5
Q

What is Fibrinogen?

A

beware derived versus measured, measured in g/L

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6
Q

What is INR?

A

Internationally standardised ratio based on the PT, technically only valid for warfarin

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7
Q

What are results affected by?

A

sampling issues and other interferences in the test tube

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8
Q

What are DOACs?

A

Direct- acting oral anticoagulants
Rivaroxaban/ apixaban

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9
Q

Where does DOAC act?

A

Factor X (prevents from activating)
IIa

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10
Q

What DOACs affect factor X?

A

apixaban
rivaroxaban

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11
Q

What DOACs act on IIa?

A

dabigatran

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12
Q

What is the benefit of DOACs?

A
  • Don’t need routine monitoring of levels
  • Standard dose
  • Act on factor X prevents it from becoming activated
  • Means no prothrombin to thrombin which means no fibrinogen= prevents a clot
  • Act on fac 2 directly
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13
Q

How DOACs affect coag panel tests?

A

Variable non- linear impact of PT & APTT

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14
Q

What clinical scenarios are DOACs used?

A

Blood clots

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15
Q

What does Warfarin inhibit?

A

Inhibits activity of vitamin K
Vitamin K dependent clotting factors= inhibited

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16
Q

What vitamin K dependent clotting factors are there?

A

IX, VII, X, II= inhibited

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17
Q

How does Warfarin affect the coag panel?

A
  • Warfarin affects both PT & APTT
  • INR is standardised way of reporting PT
  • Use INR to adjust warfarin dosing
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18
Q

What is PT sensitive to?

A
  • PT is particularly sensitive to the clotting factors affected by warfarin so can be used to accurately monitor the degree of warfarin- induced anticoagulation
19
Q

What clinical scenarios is warfarin used for?

A

Blood clots

20
Q

What are Heparins?

A
  • Naturally occurring sulphated glycosaminoglycans isolated from animal tissue, most commonly porcine intestine
21
Q

What do heparins do?

A
  • Indirectly inhibit blood coagulation, by potentiating the anticoagulant effect of antithrombin x2000
  • Accelerates the inactivation of thrombin (IIa) & factor Xa
22
Q

What is the unfractionated heparin?

A
  • Can bind to both antithrombin (AT) & thrombin (IIa)
  • Given intravenously
  • Requires a loading dose before continuous infusion
  • Requires careful monitoring
23
Q

What is low molecular weight heparin?

A
  • Smaller molecular size
  • Binds antithrombin and potentiates its inhibitory effect on Xa
  • Cannot bind thrombin (IIa)
  • Subcut injection
  • More predictable pharmacokinetics
  • Weight dependent dosing
24
Q

How does Heparin affect coag panel tests?

A
  • UFH affects APTT
  • Adjust dosing using APTT ratio
  • LMWH also affects APTT but less sensitively, depends on chain length of the LMWH, longer chain= more APTT prolongation
25
Q

What is an example of a Thrombolytic?

A

tPA

26
Q

What are the uses of thrombolytics?

A

Thrombolysis= “clot buster” medicine
Systemic versus catheter- directed thrombolysis

27
Q

What clinical cases are Thrombolytics used for?

A
  • Massive PE with haemodynamic instability
  • Acute ischaemic stroke
  • Blocked CVC line
  • Acute limb ischaemia
28
Q

Do antiplatelets affect coag panel tests?

A

NO

29
Q

What are the uses of antiplatelets?

A
  • Primary prevention- high cardiovascular risk score
  • Secondary prevention- after MI, stroke, PCI/ stenting, PVD, arterial thrombosis
  • No effect on clotting cascade
  • Involved in primary haemostasis
  • stop platelets being so sticky
30
Q

What is Haemophilia A?

A
  • X- linked
  • Recessive
  • Mainly affects males
  • Problem with factor 8 (severe end= no factor 8)
31
Q

What is Haemophilia B?

A
  • Affects gene which makes factor 9
  • Recessive
  • X linked
  • Rarer
32
Q

What are the symptoms of Haemophilia?

A

Both can cause huge pregnancy complications, huge risk of bleeding
Haemorrhages, excessive brusing

33
Q

What is the treatment for Haemophilia?

A

Preventative drugs which stop bleeding

34
Q

What does Von willebrand’s disease affect?

A
  • Important in primary and secondary haemostasis
35
Q

How does vwb affect primary haemostasis?

A

Binds platelets
Binds exposed endothelium
Forms adhesive bridge between vascular endothelium & platelets
Forms platelet plug

36
Q

How does VWD affect secondary haemostasis?

A

As it is a carrier for FVIII in the blood (otherwise FVIII would be rapidly degraded in the circulation)

37
Q

What different types of vWB disease are there?

A

Quantitive (low levels)
Qualitative (abnormal function)

38
Q

What can happen to APTT in VWB?

A

APTT can be prolonged in some forms of more severe VWB due to the resulting low FVIII levels

39
Q

What are symptoms of VWD?

A

Spectrum of severity
Often mucosal bleeding

40
Q

What is DIC?

A

Disseminated intravascular coagulopathy

41
Q

What happens in DIC?

A

-Dysregulation of normal process of haemostasis
-Balance of clotting versus bleeding (fibrinolytic) tendency
- Generation and deposition of fibrin

42
Q

What are the 2 stages of DIC?

A

Overactive clotting followed by bleeding
- Initially prothrombotic, as things continue the clotting factors & platelets get used up leading to bleeding symptoms

43
Q

How do you treat DIC?

A

Identify underlying cause:
- Severe sepsis
- Malignancies
- Obstetric complications
- Trauma
- Severe burns
- Liver failure
- Pancreatitis
- CAPS
- heat stroke/ hyperthermia
Blood product support as required

IMS- Strand 4 (4 decks)

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