Deep Vein Thrombosis (DVT) is a fairly common condition. However, it is a life-threatening condition when the clot in the vein breaks away and lodges into the lungs (pulmonary embolism). There are many risk factors for developing DVT.

Deep vein thrombosis (thrombus means blood clot) is the condition where a blood clot forms in one of the deep veins, usually in a person’s thigh or calf veins. The blood clot may either block the vein completely or partially.

It is more common in the elderly and the obese. Women are more prone to it.

DVT has gained prominence recently after headline reports of fatalities among long haul flight passengers. They have collapsed and died soon after disembarking their flights. Because of this coincidental relationship, DVT has been dubbed as “economy class syndrome”.

Causes & risk factors

3 major factors play a part in the development of DVT.

  1. Venous stasis (the pooling of blood in the veins). This may be the result of immobility, old age or heart failure.
  2. Damage of the vein due to trauma or local pressure.
  3. Increased coagulability (tendency of blood to clot) of the blood which is sometimes seen in clotting disorders, pregnancy, the use of oral contraceptives, dehydration or in some cancers.

Sitting for long periods without exercising your leg muscles is a major factor. It does not necessarily have to be in a cramped position. Passengers in first class seats in a plane have been known to develop DVT. Similarly, DVT has been seen in students sitting for many hours preparing for exams.

Risk factors for DVT include:

  • Age above 60
  • Immobility for long period of time, such as flying in an airplane, taking a long car trip or recovering in bed after surgery
  • Inherited blood clotting problem
  • Injury or surgery that reduces blood flow to a body part
  • Pregnancy or post-partum
  • Overweight/Obesity
  • Presence of varicose veins
  • Previous or current cancer
  • Intake of birth control pills or hormone therapy
  • Presence of central venous catheter.

Signs & symptoms

The symptoms of DVT include pain, tenderness, swelling and redness surrounding the area of the blood clot (usually around the calves of the legs). These symptoms may not be present immediately with clot formation. In some cases, it may take up to 2 weeks before the symptoms become apparent.


Deep vein thrombosis in itself is not that serious. The danger occurs when the blood clot or a part of it breaks off and travels to the lungs where it can block an artery. This complication is called pulmonary embolism. It is a life-threatening situation and often ends in fatalities. Emergency medical attention is imperative.

Dislodged clots can travel to other areas and cause stroke or damage to organs depending on where they get lodged.


  • Thrombolytic agents – these are agents which dissolve clots that have already formed.
  • Anti-coagulants – these are agents which prevent further clot formation.


  • Try to avoid sitting in a cramped position for too long
  • Wriggle your toes and move your ankles and knees
  • Massage muscles of the lower limbs
  • Don’t cross your legs or sit on the edge of your seat
  • Get up and walk along the aisle at least once an hour
  • Wear loose clothing
  • Avoid stockings or socks with tight bands
  • Drink plenty of water
  • Avoid alcohol
  • Don’t smoke
  • Wear special support stockings designed for travelling
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