DVT and PE Flashcards
T/F when the legs contract blood travels up the superficial veins of the leg?
False, it goes up the deep
What is thrombophilia?
A group of inherited or acquired disordered that increase a person’s likelihood of developing arterial or venous thrombosis
What can happen to the actual emboli?
DIssolution
Organisation
Recanalisation
What are some causes of hypercoagulability?
Post surgery
Post MI
Malignancy
Anti-phospholipid antibody syndrome (autoimmune)
Nephrotic syndrome
High estrogen: post partum, contraception
Obesity: increase cytokines
Certain inflammatory diseases: inflam bowel disease
Cigarette smoking?
Genetics eg Factor V Laiden mutation, prothrombin mutation, deficiencies in anti-thrombin
When are the symptoms of DVT?
They are only present in 50% of cases
Redness, swelling, warmth, pain, tenderness
What is the mechanism of the Factor V Laiden mutation? By what factor does it increase risk of DVT
Factor V is usually inhibited by the anti-coagulant activated protein C (APC) however a point mutation in factor V means APC can’t bind.
5 fold increase in the chance of DVT
Where are DVTs most commonly present?
Calves
What determines the severity of the effect of PE?
Size of the emboli
Presence of overlying lung or cardiovascular disease
T/F PE is the 4th major cardiovascular cause of death
False, it’s in the top 3
What are some risk factors for venous thrombosis?
Slow blood flow:
Immobility - leg pump
Hyperviscosity of blood
Dehydration
Cardiac failure
Endothelial dysfunction - more important in arterial thrombosis
eg direct trauma, surgical trauma, catheter damage
In what percentage of cases does death occur after PE is diagnosed?
12%
What percentage of PE patients die within one hour?
10%
What are the long term outcomes of DVT?
Varicose veins - dilation of superficial veins
Chronic venous insufficiency - venous statis, chronic oedema, pigmentation and chronic ulceration
What is the clinical presentation of PE
Variable SOB, haemoptysis, cough, syncope, pleuritic pain
T/F Blood usually travels from superficial veins to deep veins in the leg?
True
Where are most clinically significant DVTs present?
Thighs and pelvis - more likely to embolise
Where do veno-thrombi most commonly arise?
Deep veins of the legs
Where are some other sites of venous thrombosis?
Upper arm
Hepatic and portal veins
Cerebral venous sinuses
Mesenteric veins
What are some preventions for DVT?
Exercise
Mobilisation
Prophylactic drugs
Compression stocking
Lifestyle
What makes venous thrombi so red in colour?
A relatively high proportion of RBCs cf to fibrin and platelets
What is the pathophysiology of PE?
Development of hypoxaemia
Local vaso-occlusion and wide spread reflex vasoconstriction > RV stress, dilation and contractile dysfunction
Constriction of airway distal to bronchi
Decrease pulmonary compliance due to haemorrhage and loss of surfactant
What are the 3 factors that make up Virchow’s triad?
Vessel wall
Blood composition
Blood flow
What are some outcomes of PE?
DEATH if >60% of vascular bed is occluded
cor pulmonale
dyspnoea
Pulmonary infarction (usually only if underlying cardio disease as bronchial arteries supply O2)
Which veins are DVTs most common in?
Popliteal (thigh)
Femoral (thigh and pelvis)
