89 - Venous Thrombosis and Pulmonary Thromboembolism Flashcards
Most common preventable cause of death in hospitalised patients
Pulmonary thromboembolism
Clot
A solid mass composed of blood components which forms after death
Thrombus
Solid mass composed of blood components formed in an artery of vein during life
Where do thrombi often form?
Deep veins of the lower limbs
Deep veins of lower limb 1 2 3 4
Distal to proximal:
Anterior, posterior tibial veins
Popliteal vein
Femoral vein
Iliac vein (in the pelvis)
Most important venous plexus in lower limb
In soleus muscle
Superficial veins of the lower limb
Great and small saphenous veins
Location of formation of venous thrombi
Form upstream of valve.
Become more occlusive, thicker.
Feature of growth of venous thrombi
Can propagate up- and downstream of where thrombus began forming.
Why are venous thrombi red?
Form in an environment of low flow.
Have lots of RBCs.
Structure of venous thrombi
Lines of Zahn.
Alternating layers of red (RBC) and pink (platelets and fibrin)
Thrombi that are often occlusive
Venous thrombi
When are venous thrombi more likely to embolise?
When recently-formed.
Examples of changes to vessel wall that can predispose to thrombi
Trauma from catheterisation.
Bacterial infection of vessel wall.
Polycythaemia
Condition where too many RBCs are produced.
Can’t be cured, only can control symptoms.
Predisposes to thrombosis.