Thromboembolic diseases Flashcards
What is an ecchymosis?
A common type of bruise
What is meant by a blood clot?
A build up of coagulated blood that forms outside of the blood vessels
What is meant by a thrombus?
A build up of coagulated blood that forms inside the blood vessels
What measurement is used to measure the intrinsic pathway of the coagulation cascade?
Prothrombin Time (PT)
What measurement is used to measure the extrinsic pathway of the coagulation cascade?
Activated Partial Thromboplastic Time (APTT)
What is Virchow’s triad of thrombosis risk factors?
- Endothelial injury
-Turbulent blood flow
-Hypercoagulable blood
What are some primary conditions that can cause hypercoagulable blood?
Factor V Leiden
Protein C deficiency
Protein S deficiency
Antithrombin III deficiency
What are some secondary causes of hypercoagulable blood?
Prolongued immobility
Significant tissue injury
Anti-phospholipid syndrome
Myocardial infarction
Atrial Fibrillation
Cancer
Oral contraceptives
Smoking
Renal diseases
Cardiomyopathy
What are some ways in which cancer can cause hypercoagulable blood?
Tumours produce:
- Tumour Produced Tissue Factor
- Mucin
- Cytokines
These all activate the coagulation cascade
Chemotherapeutic agents can also cause endothelial injury
Marantic Endocarditis caused by cancer can also cause thrombosis (This is inflammation of a heart valve, not caused by infection)
What is an embolus?
A thrombus that has been mobilised into the vasculature, to a point where it gets trapped
What is the most common path of an embolus?
Forms in the deep veins of the calf
Iliac veins
Inferior vena cava
Right atrium
Right ventricle
Pulmonary arteries - causing pulmonary embolism
What is the visual sign of a pulmonary embolism on a chest X-ray?
A wedge (Thin triangle) shaped infarction
What is ischaemia?
Insufficient blood supply
What is infarction?
Death of tissue as a result of ischaemia
What are some other common types of embolism?
Air embolism
The Bends
Amniotic Fluid embolism
Fat embolism
Tumour embolism
Septic embolism
What is an air embolism?
Occlusion of a vessel by a significant amount of air in the blood
How much air is required in injection to cause an air embolism?
Around 100ml of air
What is the Bends?
A condition present usually in divers
It occurs as divers breath in air at very high pressures, which results in a large amount of dissolved gas (Nitrogen) in the blood
When the pressure reduces, nitrogen bubbles out of solution and can occlude the vessel
What occurs in an amniotic fluid embolism?
This is a rare complication of child birth, present in 1/40,000 births
It is the 5th most common cause of maternal mortality
It is caused by a tear in the placenta or uterine vessels, with a secondary infusion of amniotic fluid or foetal matter
Foetal squamous cells and hair can be found in the pulmonary vessels
What occurs in a fat embolism?
Fat and bone marrow leak into the blood vessels after a large skeletal injury
It occurs in 90% of significant injuries but only 10% of these show symptoms
It has a delayed onset of 1-3 days after the injury, with a distinct clinical syndrome
What occurs in a tumour embolism?
Tumours (Especially mucinous tumours) are thrombogenic and can fall apart easily
This means that they are more likely to cause coagulation and thrombosis, which can then embolism
What occurs in a septic embolism?
Specific intravascular infections cause thrombus formation
These infections include:
- Mycotic aneurysms
- Infective endocarditis
What are splinter haemorrhages?
Small haemorrhages under the fingernails, caused by an embolism
