8. Thrombotic disorders

Question 1

What is primary heamostasis

Answer 1

Blood clots

Question 2

What is the clotting process?

Answer 2

Insoluble fibrin formation

fibrin cross linking

Question 3

How are clots broken down

Answer 3

Urokinas and tissue plasminogen activator cleave plasminogen into plasmin.

Plasmin degrades fibrin

Question 4

What is a thrombus

Answer 4

A clot where there shouldn’t be one

Question 5

What is a thromboembolism

Answer 5

A clot arising in the wrong vessel

Question 6

What leads to thrombosis?

Answer 6

Stasis, hypercoagulability, vessel damage (virchow’s triad)

Don’t necessary need all three to make a clot

Question 7

Give an example of some of the factors that cause thrombosis?

Answer 7

Stasis- bed rest, travel

Hypercoagulability- pregnancy(excess oestrogen), trauma

Vessel damage- atherosclerosis

Question 8

How do you categorise thrombosis?

Answer 8

Arterial

Venous

Micro vascular

Question 9

Was causes an arterial thrombus

Answer 9

“White clot” platelets and fibrin

Results in ischaemia and infarction

Principally secondary to atherosclerosis rupture

Question 10

Give some examples of arterial thromboembolism and how they present?

Answer 10

Coronary thrombosis

Cerebrovascular thrombo

Question 11

What are the risk factors for arterial thrombosis?

Answer 11

Age
Smoking
Sedentary lifestyle
Hypertension
Diabetes
Obsesity
Hyper cholesterolaemia

Question 12

How do you manage arterial thromboembolism?

Answer 12

Primary prevention- lifestyle modification, treatment of vascular risk factors

Acute presentation- thrombolysis, antiplatelet/ anticoagulant drugs, PCI, limb ischemia- amputation

Secondary prevention- medications to reduce secondary event e.g. clopidogrel,aspirin,

Question 13

What does rivoroxebam and aspirin do?

Answer 13

Very good at better outcomes of secondary prevention

Question 14

What is a Venus thrombus?

Answer 14

Red thrombus- fibrin and red cells

Results in back pressure

Principally due to stasis and hypercoagulability

Question 15

What is post thrombotic syndrome?

Answer 15

Backflow of blood due to floppy valves.

Leads to hyperpigmentation, lower leg swelling and redness.

Very severe cases cause venous ulceration

Question 16

What are common sites for venous thromboembolism?

Answer 16

Deep vein thrombosis
Pulmonary embolism
Visceral venous thrombosis
Intracranial venous thrombosis
Superficial thrombophlebitis-managed differently
Acute pancreatitis, biliary tree disease- mesenteric vein and splenic vein
Cervical rib- upper limb DVT

Question 17

What are the risk factors for venous thrombosis?

Answer 17

Increasing age
Pregnancy
Hormonal therapy
Tissue traumaImmobility
SurgeryObesity
Systemic disease
Family history- main risk is venous disease in first degree relatives

Question 18

What systemic disease can cause venous thrombosis

Answer 18

Cancer- GI cancer, blood malaignancies
Myeloproliferative neoplasm
Autoimmune disease- IBD, connective tissue disease, antiphospholipid syndrome

Question 19

How is venous thrombosis diagnosed?

Answer 19

Wells score- most widely used.

Genes score

D-Dimer- not applicable in pregnancy

Imaging- Doppler ultrasound (veins compress, arteries don’t. DVT won’t compress),

V/Q scan good. CXR, CT pulmonary angiogram

Question 20

What is the aim of management?

Answer 20

Prevent clot extension

Prevent clot embolisation

Prevent clot recurrence in long term treatment

Question 21

What is the job of anticoagulants in venous thrombosis?

Answer 21

Most anticoagulants don’t work directly on the clot they act on the step before the clot is formed.

Anticoagulants prevent the initial clot getting bigger.Anticoagulants for minimum of three months.

Re-assess and if they have long term risk factors they need further prophylaxis

Question 22

What drugs can be used to treat venous thrombosis?

Answer 22

LMWH- malignancy, Coumarin (warfarins)- esp. if they have metallic heart valve

DOAC- direct oral anticoagualants (avoid pregnancy)

Thrombolysis only in selected cases (massive PE)

Question 23

What is heritable thrombophilia?

Answer 23

An inherited predisposition to venous thrombosis

Common factor: V Leiden mutation

Also common: prothrombin

Rare- antithrombin deficiency (risk of future clots very high patients present v young), protein C deficiency, protein S deficiency

Question 24

What is micro vascular thrombosis?

Answer 24

Platelets and/or fibrin

Results in diffuse ischaemia

Principally in disseminated intravascular coagulation

Question 25

What is Disseminated intravascualr coagulation?

Answer 25

Systemic coagulation,
occurs in Septicaemia Malignancy Eclampsia

Causes tissue ischaemia:Gangrene, organ failure

Consumption of platelets and clotting factors lead to bleeding.