Deep Vein Thrombosis (DVT) Flashcards
What anatomical structures are affected by DVT?
The deep veins of the leg (femoral and popliteal veins) and pelvis (iliac veins)
What physiology is affected by DVT?
The return of deoxygenated blood back to the heart via the inferior vena cava and the on to the lungs via the pulmonary artery
What abnormality causes DVT?
Blockage of the vein by a blood clot (thrombosis)
Where does the thrombus usually occur, and which veins does this affect?
First appears in calf but may extend above the knee via the femoral vein
It may travel through iliac veins into the pelvis
And into the abdomen through the inferior vena cava
Which condition is associated with DVT?
Thrombophilia
This is the tendency to develop thrombosis
It expresses itself with recurrent thromboses
What do 35% of DVT patients also have?
At least one hereditary thrombophilia
What are the inherited thrombophilias which DVT patients may also have?
Deficiencies in anticoagulation factors - protein C, protein S or antithrombin
mutations in the factor V and prothrombin genes
What are the most common risk factors for DVT?
Recent surgery or hospitalisation
What environmental factors increase risk of DVT?
- advanced age
- obesity
- infection
- immobilisation
- use of combined forms of hormonal contraception
- tobacco usage
- air travel
What are the symptoms of DVT experienced by patients?
- swelling of the right or left calf
- pain in the calf
There may be no symptoms related to the leg, but sudden pulmonary embolus occurs
What are the clinical signs of DVT?
- swelling and redness of the leg
- dilation of surface veins
- tenderness over veins when applying gentle pressure
Is physical examination used in diagnosing DVT?
Yes but it is unreliable for excluding the diagnosis of DVT
What would an ultrasound of the leg show in a DVT patient?
Absence or reduction of venous flow and presence of thrombus within veins
What test is used clinically to indicate that a thrombus is occurring?
What does it show?
Test for D-dimer levels
It shows that a thrombus is occurring and that the blood clot is being dissolved by plasmin
What is D-dimer?
A cross-linked fibrin degradation product
