ILA 4 - Thrombosis

Question 1

4 steps of platelet plug formation

Answer 1

Damage to a blood vessel causes exposure of collagen.
Von Willebrand Factor (vWF) binds to collagen which acts as a molecular anchor for platelets to join.
Platelets adhere to the damaged endothelium via vWF. When platelets adhere, they activate and degranulate– their shape changes and they release chemicals that keep the vessel constricted and draw more platelets to the damaged area. This positive feedback loop continues.
The aggregation of platelets results in the formation of a plug that temporarily seals the break in the vessel wall.
Following formation of the platelet plug, coagulation is activated to form a fibrin mesh which stabilises the platelet plug.

Question 2

Describe the coagulation cascade?

Answer 2

series of steps responding to bleeding caused by tissue injury.

you get a blood clot.

Question 3

Blood Clot formation

Answer 3

Primary Homeostasis - forms unstable clot

Secondary Homeostasis: Coagulation cascade stabilised plus = stop blood flow = allow time for repairs.

Question 4

Info about clotting factors

Answer 4

they are a serine protease
inactive form = zymogens
place with glycoprotein co-factor = activated

with an “a”

Question 5

Give the 3 pathways of coagulation and the clotting factors associated

Answer 5

extrinsic : 3 ,7 , 10
intrinsic : 12 11 8 9 10
common : 10, 5, 2, 1, 13

Question 6

what does factor 7 need in extrinsic pathway to activate?

Answer 6

vit k

Question 7

Signs and Symptoms of Arterial Thrombosis

Answer 7

1. Diminished absent pulse
2. pain- intermittent claudication - constant
   cold to cold temp
   nails thickened and ridged
   skin-dependent rubor

6 P’S - PARESTHESIA,PALLOR, PAIN , PULSELESS, PERISHINGLY COLD, PARALYSIS

THROMBOSIS LEADS TO ABOVE MORE SLOWLY. ARTERIAL EMBOLUS RESULTS IN SX QUICKER.

Question 8

Signs and Symptoms of Venous Thrombosis

Answer 8

1. pulse present
2. pain,aching,cramping
3. skin pigmentation in gaiter area - medial and lateral malleolus

Question 9

Comparisons of Arterial vs Venous Thrombosis

Answer 9

Arterial:
Occur under high shear stress.
White clot
mi and stroke
antiplatelet agent

venous:
low shear stress
red clot
dvt, pe
anticoagulation

Question 10

Describe Virchows Triad

Answer 10

Hypercoagulability
Venous Stasis
Endothelial Dysfunction

Question 11

what blood test would you do to confirm dvt?

Answer 11

D-Dimer
Fibrin degradation production = released from cross-linked fibrin fibres during fibrinolysis.

raised in:
1. DVT/PE
2. DIC
3. INFLAMMATION EG: INFECTION OR MALIGNANCY

Question 12

Explain the action of heparin in relation to coagulation cascade

Answer 12

GLYCOAMINOGLYCAN

binds to antithrombin and increases its activity.
indirect thrombin inhibitor

Question 13

Explain warfarin action in relation to coagulation cascade

Answer 13

prevents synthesis of factors 2,7, 9, 10
antagonist of vit k
long half life
prolonged prothrombin time

target inr: 2-3 . higher range: 3-4.5

Question 14

Explain DOAC action in relation to coagulation cascade

Answer 14

eg: rivaroxaban - xa inhibitor

directly act on factor 2 or 10.
used for extended thromboprophylaxis and AF tx and dvt/pe tx

ci: pregnancy
cannot use to treat inr of 3-4.5

Question 15

fatal comp of dvt

Answer 15

pulmonary embolism

symptoms:
dyspnoea, pleuritic chest pain, cough, orthopnoea, wheezing, syncope

signs:
tachypnoea, dvt signs: edema, tenderness. hypoxia, tachycardia, 4th heart sound , reduced breath sounds, fever, hypotension

Question 16

advice for long haul flight?

Answer 16

wear loose comfortable clothes
drink water
no alcohol
no sleeping pills
calf exercises every 30 mins