Deep vein thrombosis is a blood clot that forms in a vein inside the body. It is important to note that this clot might partly or fully block the flow of blood through a vein. In most cases, it occurs in the lower leg, pelvis or thigh but can also form in other body parts including the brain, arm, liver, intestines or kidney.
Danger of deep vein thrombosis
Even though deep vein thrombosis is not itself life-threatening, the blood clot might break free and move via the bloodstream where it might become embedded in the blood vessels within the lungs which is called as pulmonary embolism. This condition is considered dangerous and necessitates immediate diagnosis and treatment.

Deep vein thrombosis can also result to issues in the legs which is called chronic venous insufficiency or post-thrombotic syndrome. The condition is characterized by the accumulation of blood, increased pressure, chronic leg swelling, skin discoloration and leg ulcers or venous stasis ulcers.
Indications
Deep vein thrombosis can form in one leg or one arm. Not all cases with the condition will develop symptoms, but can include the following:
- Swelling of the arm or leg (occurs abruptly)
- Tenderness or pain in the leg (this occurs only while walking or standing)
- Reddened or discolored skin
- Enlarged veins close to the skin surface
When it comes to superficial venous thrombosis or phlebitis, it is a blood clot that forms in a vein near the skin surface. This type of clot does not move to the lungs if they travel from the superficial scheme into the deep venous system first.
Quick Note / Disclaimer
The material posted on this page on deep vein thrombosis is for learning and educational purposes only. To learn to recognize and manage this circulatory condition, register for a first aid and CPR course with Mississauga First Aid.