DVT/PE Flashcards
Intrinsic DVT Risk Factors
A history of DVT.
Cancer (known or undiagnosed).
Age over 60 years.
Being overweight or obese.
Male sex.
Heart failure.
Medical illness, for example acute infection.
Acquired or familial thrombophilia.
Inflammatory disorders (for example, vasculitis, inflammatory bowel disease).
Varicose veins.
Smoking.
Risk factors that temporarily raise the likelihood of DVT include:
Recent major surgery.
Recent hospitilisation.
Recent trauma.
Chemotherapy.
Significant immobility (bedbound, unable to walk unaided or likely to spend a substantial portion of the day in bed or in a chair).
Prolonged travel (4hours +).
Significant trauma or direct trauma to a vein (eg intravenous catheter).
Hormone treatment (feg oestrogen-containing contraception or hormone replacement therapy).
Pregnancy and the postpartum period.
Dehydration
What are the 3 mechanisms involved in DVT Pathophysiology? (Virchows triad)
Blood vessel damage
Venous stasis
Hypercoagulability
What is the difference between DVT and VTE?
DVT: blood clot formation
VTE: movement of embolus from original site to another location
How does massive PE Pathophysiology lead to obstructive shock?
obstruction in deep veins of legs → decreased blood flow (ventilation occurs, no perfusion) → ↑ pulmonary artery pressure → ↑ Right heart workload to maintain pulmonary blood flow → right ventricular ischaemia → ↓ CO, BP → shock
Which investigations for likely DVT (more than 2 wells score)?
For people who arelikelyto have DVT(based on the results of the two-level DVT Wells score):
- Proximal leg vein US scan
if not possible then:
- order D-dimer test (to rule out DVT)
- arrange interim anticoagulation
Which investigations for unlikely DVT (less than 2 wells score)?
For people who areunlikelyto have DVT(based on the results of the two-level DVT Wells score):
- Offer D-dimer test (within 4h)
- Offer interim anticoagulation
How to interpret D-dimer results in suspected DVT?
Positive D-dimer:
offer a proximal leg vein ultrasound scan
Offer anti-coag therapy
Negative D-dimer:
Stop anti-coag therapy
Consider alternative diagnosis
What to do when wells score is more than 4 for PE?
Arrange hosp admission + CTPA (or V/Q Scan if CTPA is contraindicated),
offer anticoag therapy
What to do when wells score is less than 4 for PE?
unlikely PE, arrange D-dimer to rule out PE(within 4h)
offer anticoag therapy
How to interpret D-dimer results in suspected PE?
If D-dimer positive: arrangeCTPA or V/Q scan – however D-dimer is NOT diagnostic of PE
If D-dimer negative: stop anticoag therapy once PE ruled out, unlikely PE, consider alternative diagnosis
What does primary haemostasis involve?
initiation and formation of the platelet plug
What does secondary haemostasis involve?
coagulation cascade to form fibrin mesh to add strength and complete clot
3 pathways of coagulation cascade:
intrinsic
extrinsic
common
What is the common pathway?
activation of factor x into xa
