Everything about deep vein thrombosis

What is deep vein thrombosis ?

Deep vein thrombosis is caused by the formation of thrombus ( blood clot ) most commonly on the thigh or calf.

What cause deep vein thrombosis ?

Deep veins of the leg are more prone to blood stasis as venous return is dependent on the usage of surrounding muscles and works against gravity.

What is the statistic of deep vein thrombosis?

Deep vein thrombosis is extremely common. In hospitalised patients, up to 50 % have some form of venous statsis.

What is associated with deep vein thrombosis ?

Deep vein thrombosis is associated with oral contraceptive pills, post-surgery, prolonged immobility, pregnancy, dehydration, smoking, polycythaemia, thrombophilia disorder as well as active malignancy.

How does deep vein thrombosis present ?

Patient usually present to the hospital with painless swollen lower limb,

How does deep vein thrombosis present ?

Deep vein thrombosis usually present with localised redness, warmth and swelling. There is also an increase in the leg circumference. Patient may also present with changes in the colour of the veins and evidence of varicose formation.

We able to identify the risk of deep vein thrombosis by using the Wells Clinical Prediction Guide that consists of :

  1. -active cancer ( 1 point )
  2. -entire leg swelling ( 1 point )
  3. -recently bedridden for more than 3 days or major surgery less than 4 weeks ( 1 point )
  4. -localised tenderness along the distribution of the deep veins systems ( 1 points )
  5. -calf swelling more than 3 cm compare to the normal leg.( 1 point )
  6. -present of collateral superficial veins ( 1 point)
  7. -paralysis or recent plaster immobilisation ( 1 point )
  8. -pitting oedema ( greater in the symptomatic leg ) ( 1 point )

Each of the above scores 1 point. Scores of more than 2 indicates high risk, while 1-2 is moderate risk and 0 is low risk.

The patient may also present with increase respiratory rates, pulse oximetry and pulse rates.

What is the pathology behind deep vein thrombosis ?

The mechanism that leads to deep vein thrombosis formation are summed up with Virchow's triads and consists of injury to the vessel wall, blood flow disturbance and blood hypercoagulability

What is the investigation to detect deep vein thrombosis?

The investigation that is required to detect deep vein thrombosis includes:

Doppler ultrasound: Gold standard. It has a good sensitivity for femoral veins however less sensitive for calf veins.

Impedance plethysmography: Changes in blood volume results in changes of electrical resistance of the lower limb. Poor sensitivity for calf veins.

Bloods: None are diagnostic with D dimers ( fibrinogen degradation products) very sensitive but very non specific and only useful as negative predictor. If indicated, a thrombophilia screen should be sent. Prior to starting anti coagulation full blood count ( platelet count prior to starting heparin), urea and electrolytes ( to check renal function ) and clotting.

ECG, CXR and ABG; if there is suggestion that there might be pulmonary embolism, these should be performed. Look for ST, S1Q111T111, axis deviation and hypoxia.

How to manage deep vein thrombosis ?

Management includes anticoagulation. Patient should be treated with heparin while awaiting therapeutic INR from warfarin anticoagulation ( INR =~ 2.5). Deep vein thormbosis not extending above knee , in some cases may be observed or treated with anticoagulation for 3 months while those extending beyond knee require anticoagulation for 6 months. Reccurence deep vein thrombosis may required long term warfarin. If active anticoagulation is contraindicated and there is high risk of embolisation, placement of inferior vena cava filter, eg, greenfield filter, by interventional radiology is indicated to prevent embolus to the lungs.

In term of prevention usage of graduated compression stocking, mobilisation if possible. At- risk groups ( immobilised hospital patients) should consider prophylactic heparin such as low molecular weight heparin subcutaneously daily if no contraindication.

What is the complication of deep vein thrombosis ?

The complication include pulmonary embolism, In acute setting it can progress to venous infaction known as phlegmasia cerulae dolens. Recurrence deep vein thrombosis can eventually lead to thrombophlebitis of the deep veins , damage to the valves of the veins and chronic venous insufficiency of the lower limbs.

What is the prognosis of deep vein thrombosis?

Depends on the extents of deep vein thrombosis, below knee deep vein thrombosis generally have an excellent prognosis, more proximal deep vein thrombosis are more serious with risk of pulmonary embolism which if large may be fatal.

Acute left leg thrombosis

Phelgmasia cerulae dolen. Complication of deep vein thrombosis

Pathology of deep vein thrombosis

Pathology of deep vein thrombosis

Symptoms of deep vein thrombosis

Deep vein thrombosis treament

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