Deep Vein Thrombosis (DVT) is one of the most common medical conditions. It refers to a blood clot (thrombosis) in veins, most typically occurring in the legs, but it can occur anywhere in the body.

DVT is considered a medical emergency as there is the risk of the blood clot travelling (embolising) to the heart and lungs and causing lung damage, heart strain and even, death. This complication is known as Pulmonary Embolus (PE) and is the main reason for treating DVT as an emergency.
DVT may also lead to lifelong problems with legs sometime after one has experienced the acute event. These problems include swelling, pain, skin changes and wound formation known as the “Post Thrombotic Syndrome’.

This complication high ights why it is so important to treat DVT timeously and properly. Thus, early treatment of deep vein thrombosis is absolutely essential.


  • Symptoms will depend on which veins are affected in the leg.

  • One may experience calf pain, calf swelling or entire leg swelling.

  • If the thrombosis has travelled to the lung, one may experience shortness of breath and chest pain.

Who is at risk of DVT?

Blood will clot if it is not moving – thus anyone who does not or cannot move the legs much is at risk of the blood clots. Stroke patients, post-surgical patients or people who go on long haul flights (or other long-haul travel) are at an increased risk.

Venous blood may also not move from a narrowing of the main vein in the pelvis, reducing outflow of blood from the leg. This is typically seen on the left with significant leg swelling, but can occur on either side. It is known as the May Thurner Syndrome.

Blood usually thromboses to protect the body (such is in trauma). When blood clots, there is a complex enzyme system in place that causes the clotting. Some people may have a genetic condition affecting enzymes which cause clotting (or be deficient in enzymes that break up clots) and this may increase the chance of clotting.

Hormonal and other changes in blood parameters may also affect blood clotting and pregnancy, those taking exogenous hormones (oral contraceptive, hormone replacement therapy) and cancer patients are all considered to be procoagulable (promote clotting).

Lastly, dehydration or damage to a vein may result in clotting and thrombosis (such as having a central vein insertion or a dialysis catheter insertion). The body has a remarkable capacity to correct itself. Often, it is a combination of risks that eventually result in a DVT.


  • A duplex doppler ultrasound is used to make the diagnosis of a DVT.

  • If the clot involves the entire leg and extends into the pelvis, a CT scan be necessary as well.

  • A blood test, called a D-dimer, may also be done (especially if there is no duplex Doppler ultrasound available).This is more a test of exclusion – i.e. if it is normal one will not have a DVT. However, if it is raised it may indicate that a thrombosis is present, but it can be raised for other reasons as well.

DVT’s in Athletes

Deep Vein Thrombosis is being diagnosed and detected more frequently than before. It has also been known to occur in athletes.

See other common conditions