What is thrombosis?What is thrombosis?

Thrombosis occurs when a blood clot, also known as a thrombus, forms in a blood vessel and stops blood from easily flowing within your circulatory system. Different types of thrombosis are classified based on where the blood clot forms in the body.

  • Superficial thrombosis – Refers to a blood clot in a vein near the skin
  • Arterial thrombosis – When a blood clot has developed in an artery
  • Deep vein thrombosis – Occurs when a blood clot forms in a major vein, usually in the leg
  • Pulmonary embolism – Occurs when a blood clot forms in vessels in the lung


To diagnose thrombosis, your doctor will talk with you about your health and conduct a general examination. If they suspect a blood clot, you may require further testing such as an ultrasound, blood test or x-ray.


Treatment of thrombosis depends on the kind of thrombosis you have and the severity of the blood clot. For more severe cases, hospitalisation and surgery may be needed to remove the blood clot or widen an artery. Generally medications are used to dissolve the blood clots, with bandaging and compression stockings used to relieve any pain or swelling.

To prevent further blood clots from developing, anticoagulation medicines may be prescribed. These medicines thin the blood, making it less likely to clot, however may need to be taken for months or even years.

Frequently asked questionsFrequently asked questions

What are the symptoms of thrombosis?

Symptoms of thrombosis depend on the location of the blood clot. They may include:

  • Pain, redness and swelling
  • Chest pain and shortness of breath – clots associated with deep vein thrombosis can travel to the lungs, causing a pulmonary embolism
  • Weakness on one side of the body, problems speaking and difficulties with balance and walking – if you have an arterial thrombus in the heart, head or neck, this can cause a heart attack or stroke.
What causes thrombosis?

There are many risk factors associated with thrombosis. Arterial thrombosis is often caused by fatty deposits clogging the arteries.

There is a higher chance of developing superficial or deep vein thrombosis if you:

  • Have recently had surgery
  • Are a smoker
  • Have been immobile for extended periods of time
  • Are pregnant
  • Have cancer
  • Have increased oestrogen levels (due to hormone therapy or oral contraceptive medication)
  • Have a blood disorder
  • Are dehydrated
  • Have a history of thrombosis
  • Have a family history of thrombosis
How can thrombosis be prevented?

The most important thing you can do to reduce your risk of thrombosis is prioritise your health, by:

  • Quitting smoking
  • Reducing alcohol intake
  • Maintaining a healthy weight
  • Exercising regularly
  • Ensuring a healthy and nutritious diet

Wearing compression stockings, especially on long flights and following surgery, and regular exercises can also prevent blood clots. If you are at risk of thrombosis, your doctor may recommend certain medications to thin your blood or reduce your cholesterol and blood pressure.

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