Haemostasis Flashcards

1
Q

what is haemostasis

A

Haemostasis: blood (haem) stop/stand still (stasis)
The haemostasis is strictly controlled

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2
Q

what are the 5 major components of the haemostatic system?

A
  1. Blood vessels
  2. Platelets
  3. Coagulation factors
  4. Coagulation inhibitors
  5. Fibrinolysis
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3
Q

what is primary haemostasis?

A
  1. Platelets respond to the vessel wall
    injury
  2. Platelets adhere to the vessel wall
  3. A primary platelet plug is formed
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4
Q

what is secondary haemostasis?

A
  1. Activation of the intrinsic and
    extrinsic coagulation pathways
  2. Activation of the common pathway
  3. Fibrin strand formation and
    strengthening of the platelet plug
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5
Q

describe Blood Vessels in Haemostasis

A
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6
Q

describe Von Willebrand Factor (vWF)

A
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7
Q

discuss characteristics of Platelets

A
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8
Q

describe platelet storage granules

A
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9
Q

describe the primary haemostasis process

A
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10
Q

what are the results of primary haemostasis?

A

Primary haemostasis forms a temporary and weak platelet plug

Unstable and needs strengthening

secondary haemostasis

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11
Q

what is the need for secondary haemostasis?

A

A weak platelet plug needs strengthening by coagulation
factors (secondary haemostasis)

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12
Q

what is secondary haemostasis strengthened by

A

Coagulation factors are mostly proenzymes (zymogens)

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13
Q

where are most coagulation factors synthesised?

A

liver

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14
Q

what do proenzymes require to carry out their function

A

Proenzymes require activation to carry out their function
* Active form of a coagulation factor is denoted ‘a’

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15
Q

what are the four stages of haemostasis?

A
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16
Q

Explain the Coagulation Cascade

A
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17
Q

explain the extrinsic pathway

A
18
Q

explain the intrinsic pathway

A
19
Q

explain the common pathway

A
20
Q

What happens to the clot afterwards?

A
21
Q

Why do we not get clots all the time?

A
22
Q

Why do we not get clots all the time?

A
23
Q

When to get tested?

A
  • Unexplained or excessive bruising or prolonged bleeding,
    either spontaneously or from injuries or surgery.
  • For women and girls who experience very heavy periods.
  • Relative with a known hereditary coagulation factor deficiency.
  • To follow up treatments after receiving a diagnosis to see that
    your treatment is working.
  • Other medical conditions that affect coagulation factors.
  • As part of investigations for Thrombophilia (increased clotting).
24
Q

Tests used to evaluate clotting and bleeding

A
  • Standard tests
  • Full blood count (FBC)
  • Blood film
  • Coagulation tests
  • PT, APTT and TT
  • Analysis of clotting inhibitors like Protein C and Protein S
  • Platelet function tests
  • PFA-100 and lumi-aggregometry
  • Flow cytometry for receptor expression
  • A test to rule out blood clots in the body
  • D-dimer
25
Q

what are the Specimen Requirement?

A
26
Q

Laboratory Diagnosis

A
27
Q

Prothrombin Time (PT)

A
28
Q

Activated Partial Thromboplastin Time (APTT)

A
29
Q

Thrombin Time (TT

A
30
Q

fibrinogen quantification

A

Fibrinogen quantification is a laboratory test that measures the amount of fibrinogen in the blood. Fibrinogen is a protein that is essential for blood clotting. The normal fibrinogen levels for an adult range between 200 and 400 milligrams/deciliter. The test measures fibrinogen levels as grams per litre. A typical fibrinogen level is between 4 grams per litre or 200 to 400 milligrams per deciliter. The Clauss assay is a functional test that measures the time taken for plasma to clot in a high concentration of thrombin, with a comparison against a reference plasma calibration curve. It is the gold standard for fibrinogen quantification

31
Q

vWF test

A
32
Q

Measuring Protein C

A
33
Q

Measuring Protein S

A
34
Q

Measuring platelet function

A
35
Q

Flow cytometry

A
36
Q

Summary: Laboratory Tests

A
  • The coagulation cascade can be evaluated with multiple tests:
  • PT – extrinsic and common pathway
  • APTT – intrinsic and common pathway
  • TT – functional fibrinogen
  • Protein C and Protein S – Protein deficiency that leads to blood clots
  • Platelet function can be measured using lumi-aggregometry or the PFA-100.
  • Flow cytometry is a good complement to investigate receptor levels
37
Q

treatments

A

Aspirin
* Warfarin
* Heparin
* Purinergic receptor inhibitors

38
Q

Aspirin (acetylsalicylic acid)

A
39
Q

Heparin

A
40
Q

Purinergic receptor inhibitors

A
41
Q

Warfarin

A