Deep Vein Thrombosis (DVT)

Deep vein thrombosis (DVT) is a clot in the main deep veins of the leg.  DVT's can occur spontaneously or after surgery (particularly orthopaedic surgery) or after sitting for prolonged periods (generally > 4 hours) eg plane or car travel.

Symptoms of a DVT include: painful swollen leg.

DVT is a significant concern for two reasons. 

1.  The clot may break off from the deep vein in the leg and travel to the lung causing a pulmonary embolus (PE).  A pulmonary embolus may not cause any symptoms if it is small and quickly broken down by the body but if the clot is large it can cause severe chest pain, shortness of breath and/or cough with or without blood.  A very large PE can be fatal.

2.  The clot in the leg can cut off the main return of blood back from the legs to the heart and lungs causing a "post phlebitic" syndrome which leads to a severely swollen leg.

Prevention of DVT

If you are on a long journey requiring prolonged sitting (>4 hours) whether by car, plane or train you should think about DVT prevention.  Wear Class 1 or 2 compression hosiery (flight socks), ensure you are adequately hydrated, avoid alcohol consumption and sedatives and walk as frequently as is practicable.  It is inactivity that creates the problem.  The foot and calf muscles are the main pumps for returning blood flow to the heart and lungs - prolonged sitting without exercising the ankle and calf leads to stasis of the blood and this may form a clot or DVT. 

Treatment of DVT/PE (venous thromboembolism).

Heparin is the traditional initial method of treating DVT or PE. This used to have to be treated through an intravenous drip in hospital but is now administered by subcutaneous injection (under the skin of the abdomen) of low molecular weight heparin (LMWH) at home.  Warfarin is usually started soon after as this can be given by mouth.  Warfarin needs to reach an effective level in the blood stream and this is monitored by a test called the INR which is organised by the patients general practitioner.

 Once the INR level is stable (usually between 2-3) the LMWH (usually Clexane) can be stopped. Warfarin is then contiued for at least three months and in some cases may need to be taken permanently.