S5) Thrombosis and Embolism Flashcards

1
Q

What is a thrombosis?

A

A thrombosis is the formation of a solid mass from the constituents of the blood, within the circulatory system

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2
Q

There are three fundamental predisposing factors to thrombosis.

What is this called?

A

Virchow’s triad

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3
Q

Identify the three predisposing factors to thrombosis as outlined in Virchow’s triad

A
  • Abnormalities of the flow of blood
  • Abnormalities of the blood vessel wall
  • Abnormalities of the constituents of the blood
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4
Q

State two possible abnormalities in the flow of blood

A
  • Stagnation
  • Turbulence
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5
Q

State three causes for abnormalities in the blood vessel wall

A
  • Atheroma
  • Direct injury
  • Inflammation
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6
Q

State three causes for abnormalities in the constituents of the blood

A
  • Smoking
  • Post-partum
  • Post-operation
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7
Q

Describe the appearance of arterial thrombi

A
  • Pale
  • Granular
  • Lines of Zahn
  • Lower cell content
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8
Q

Describe the appearance of venous thrombi

A
  • Soft
  • Gelatinous
  • Deep red
  • Higher cell content
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9
Q

What are the 5 possible outcomes of a thrombosis?

A
  • Lysis
  • Propagation
  • Organisation
  • Re-canalisation
  • Embolism
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10
Q

In three steps, describe the following outcome of a thrombosis: lysis

A

⇒ Complete dissolution of thrombus (small)

Fibrinolytic system active

⇒ Blood flow re-established

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11
Q

In three steps, describe the following outcome of a thrombosis: propagation

A

⇒ Progressive spread of thrombosis

⇒ Spreads distally in arteries

⇒ Spreads proximally in veins

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12
Q

In two steps, describe the following outcome of a thrombosis: organisation

A

⇒ Ingrowth of fibroblasts and capillaries (similar to granulation tissue)

⇒ Lumen remains obstructed

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13
Q

In two steps, describe the following outcome of a thrombosis: re-canalisation

A

Blood flow re-established but usually incompletely

1/more channels formed through organising thrombus

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14
Q

In three steps, describe the following outcome of a thrombosis: embolism

A

⇒ Part of thrombus breaks off

⇒ Travels through bloodstream

Lodges at distant site

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15
Q

What are the arterial effects of thrombosis?

A

Depends on site and collateral circulation:

  • Ischaemia
  • Infarction
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16
Q

What are the venous effects of thrombosis?

A
  • Congestion
  • Oedema
  • Ischaemia
  • Infarction
17
Q

What is an embolism?

A

An embolism is the blockage of a blood vessel by solid, liquid or gas at a site distant from its origin

18
Q

What is the most common type of embolism?

A

Over 90% of emboli are thrombo-emboli

19
Q

What are other types of embolism?

A
  • Air
  • Amniotic fluid
  • Nitrogen
  • Medical equipment
  • Tumour cells
20
Q

Outline the four different pathways for thromboemboli

A
  • From systemic veins → lungs (pulmonary emboli)
  • From the heart (via aorta) → renal, mesenteric and other arteries
  • From atheromatous carotid arteries → brain
  • From atheromatous abdominal aorta → leg arteries
21
Q

Identify common areas where emboli can occur

A
  • Pulmonary embolism
  • Coronary embolism
  • Cerebral embolism
22
Q

What is a deep vein thrombosis?

A
  • A deep vein thrombosis is the formation of a thrombus within a deep vein, most commonly the deep calf veins
  • It produces an inflammatory response (calor, dolor, rubor, tumor, functio laesa)
23
Q

Identify 5 predisposing factors to deep vein thrombosis

A
  • Immobility
  • Post-operative
  • Pregnancy and postpartum
  • Oral contraceptives
  • Severe burns
24
Q

How does one prevent DVT?

A
  • Prophylaxis for high-risk patients
  • Heparin sub-cutaneously
  • Leg compression during surgery

I. TED stockings

II. ‘Flowtron’ boots

25
Q

What is the treatment for DVT?

A
  • Intravenous heparin
  • Oral warfarin
26
Q

What is a pulmonary embolism?

A
  • A pulmonary embolism is a sudden blockage of a pulmonary artery in the lung, usually due to a deep vein thrombosis
  • It presents with chest pain, shortness of breath, coughing and blood stained sputum
27
Q

Identify and describe the three forms of pulmonary embolism

A
  • Massive PE – >60% reduction in blood flow (rapidly fatal)
  • Major PE – medium-sized pulmonary vessels blocked (SOB ± cough, blood stained sputum)
  • Minor PE – small peripheral pulmonary arteries blocked (asymptomatic/SOB)
28
Q

What is the effect of recurrent minor pulmonary emboli?

A

Recurrent minor PEs lead to pulmonary hypertension