When there is nothing left in the vein
Dangerous blood clots: thrombosis

Venous thrombosis is the occurrence of a blood clot (thrombus) in a vein. Veins are the blood vessels through which the blood flows back from the body to the heart. Leg vein thrombosis is when thrombosis occurs in the deep leg veins. In such a case the flow of the blood from the leg is disturbed and the blood can not flow back to the heart properly. This leads to the swelling of the leg, which can expand as the thrombosis progresses to the entire leg. The leg is painful (especially while walking), is thick, feels hot and can sometimes turn red-blue. It is particularly noticeable and often indicative of thrombosis when these symptoms only occur in one leg. Thrombosis may be restricted to the veins of the lower extremity (distal venous thrombosis) but it may also extend into the veins of the thigh (proximal leg vein thrombosis) and in rare cases into the pelvis.

The most significant complication of venous thrombosis is pulmonary embolism. Pulmonary embolism occurs when parts of the clot (or the whole clot) dissolve from the venous wall and are then transported with the bloodstream into the lung. This is called either a pulmonary embolism or a pulmonary infarction.

→ Causes 
There are various causes of leg venous thrombosis. It often occurs as a result of time limited risk situations, like an operation, a serious injury, a plaster cast, a long period of being bedridden, a pregnancy or childbirth, or very long (plane) journeys. The use of female hormones (the pill, hormone replacement therapy) can also increase the risk.


→ The diagnosis of vein thrombosis 

In most cases, the so-called colour coded duplex sonography is used. With this painless examination, thrombosis can, with certainty, be verified or ruled out. Sometimes a blood test is also taken, the so-called D-Dimer-Test. Increased D-Dimer levels are not proof of the presence of thrombosis. However, normal D-Dimer levels exclude thrombosis with a very high probability.

→ Therapy 

Therapy of deep vein thrombosis must be done quickly to prevent thrombosis and the life-threatening complication of pulmonary embolism. The treatment consists of administering a blood thinning drug.

→ Alarm signals for suspected thrombosis

The sudden onset of pain and/or swelling in one leg can occur after an operation, during or after having a rigid dressing on a leg, a prolonged bedridden period, a pregnancy or after delivery.
If there is simultaneous breathlessness or pain in the chest, a specialist or hospital must be consulted straight away. 

Deep vein thrombosis

Deep vein thrombosis (or economy class syndrome) is caused by the knee being flexed during long-haul flights or bus trips. Theoretically there is a slight risk of thrombosis for every long-distance journey. The risk increases if several of the following conditions apply to you:

  • Aged over 40
  • Sufferer of heart failure
  • Have varicose veins and other signs of venous insufficiency
  • Take the contraceptive pill
  • Are overweight
  • Are pregnant

→ An particularly high risk is common if:

  • There is a history of thrombosis
  • Tumour diseases
  • Proved familial thrombosis
  • Gipsum dressing on legs
  • Surgery performed with high thrombosis risk shortly before a trip


  • Reserve aisle seats on plane journeys
  • Lots of movement. Regularly stand up and use the legs; while sitting: bend and stretch the ankles, repeatedly stand up; while driving: take regular breaks
  • Drink plenty of liquids (no alcohol!)
  • No sedatives or sleeping pills on flights

If the risk is high:

  • Half stockings of compression classes I to II

If the risk is higher:

  • Injection with a low-molecule Heparin shortly before travel (under the skin of the stomach)
  • For longer round trips, one daily injection