Deep Vein Thrombosis: Symptoms, Causes & Treatment

Deep vein thrombosis is a medical condition in which a blood clot forms inside one of the body's deep veins, most often in the leg or thigh. This clot obstructs the flow of blood returning to the heart, so blood pools behind it, causing swelling and pain in the affected limb.

Clots usually arise from slowed blood flow in the veins, an increased tendency of the blood to clot, or injury to the vein lining. Their risk therefore rises with prolonged sitting or lying down such as long travel or rest after surgery, as well as with pregnancy, some hormonal medications, and diseases that increase clotting.

The real danger of deep vein thrombosis lies in the possibility that part of the clot breaks off and travels with the blood to the lungs, causing what is known as a pulmonary embolism, a life-threatening emergency. Early diagnosis and treatment with anticoagulants are therefore extremely important, and prevention — through regular movement, avoiding prolonged sitting, and wearing compression stockings when needed — plays an essential role, especially for at-risk groups.

• Swelling, usually in one leg.
• Pain or tightness in the calf that worsens on standing or walking.
• Redness or skin color change and warmth in the area.
• Some cases may have no clear symptoms.

• Slowed blood flow from prolonged immobility.
• An increased tendency of the blood to clot (inherited or acquired).
• Injury to the vein lining after surgery or trauma.

• Prolonged sitting or lying down (long travel, post-surgery rest).
• Pregnancy and some birth-control pills and hormone therapy.
• Obesity, smoking, and older age.
• Cancer and some clotting disorders.

• Venous ultrasound (Doppler), the main test.
• A D-dimer blood test.
• Additional imaging when pulmonary embolism is suspected.

Anticoagulants

• Blood-thinning medications that prevent the clot from growing and new clots from forming, taken for a duration set by the doctor.

Supportive measures

• Elevating the limb, gradual movement, and compression stockings.
• Advanced procedures such as clot dissolution in selected severe cases.

This content is educational and does not replace medical advice; blood thinners are prescribed and closely monitored under medical supervision.

• Pulmonary embolism, a life-threatening emergency.
• Post-thrombotic syndrome (chronic leg pain and swelling).
• Recurrence of clotting.

• Regular movement and avoiding prolonged sitting, and standing and walking during long travel.
• Compression stockings and preventive blood thinners after some surgeries as directed by the doctor.
• Drinking fluids, quitting smoking, and keeping a healthy weight.