PBL 7: Patricia Aledambo Flashcards
What is an embolism?
a part of a clot which has broken of a thombus and moved through the circulatory system to another location where it has got stuck
What are the difference between venous and arterial thrombi?
Venous - ‘red clots’ are RBCs in a fibrin mesh
Arterial - ‘white clots’ (platelets and fibrin)
What is a pulmonary embolus?
A clot which has moved through the veins into the heart and into the pulmonary veins and has become stuck there
Where are thrombi more common?
In the veins where the blood flow is slower
What is a DVT?
Having a deep vein fully/partially blocked by a thrombus
Where do DVTs normally originate?
In deep venous sinuses in the calf muscles
Where do DVTs extend?
From venous calf muscles:
- proximally to popliteal veins or above into pelvic vasculature = symptomatic, complications
- stay below popliteal vein = normally fibrinolyse, no symptoms
What is Virchow’s triad?
3 aspects affected:
- stasis of the blood
- vessel wall abnormalities
- hypercoagulability
What are the risk factors for DVT?
Age - greater than 50 years old - hip/pelvis fracture - hip/knee replacement - spinal cord injury - major trauma - hospitalisation with acute medical illness - previous VTE - cancer - pregnancy - combine oral contraceptive pill HRT - thrombophilia
What are the difference between strong and moderate risk factors?
Strong - relation to immbolisation (stasis)
Moderate - relate to hypercoagulable states
How does DVT present?
Unilateral swelling pain erythema tenderness warmth ipsilateral oedema palpable cord (thrombosed vein)
How is DVT diagnosed?
Wells Score (need score of 2 or higher)
- ultrasound scan of legs for confirmation
- plasma D-dimer levels (fibrin degradation product non specific marker and seen with inflammation)
- venogram is gold standard (invasive and expensive)
- blood count (bleeding evidence)
What are some criteria of the Wells score?
- Active cancer and having treatment within last 6 months
- calf swelling >3cm compared to other calf by measuring 10cm below tibial tuberosity
- collateral superficial veins
- pitting oedema in affected leg
- swelling of entire leg
- localised pain
- bedridden for more than 3 days
- take 2 off if alternative diagnosis likely
When would diagnosis be excluded?
If patient is at low risk due to Wells score, no D dimer done
If greater risk, D dimer and ultrasound done to make sure
If high risk, ultrasound performed irrespective of D dimer result
What are some differential diagnoses?
Ruptured Baker's cyst Cellulitis Compression of iliac veins Congestive cardiac failure Musculo-tendinour (trauma, haematoma) CT disorder
