Deep Vein Thrombosis (DVT): Causes, Symptoms & Treatment

Deep vein thrombosis (DVT) is a condition in which a blood clot (thrombus) forms in one or more of the deep veins in the body, most commonly in the legs. DVT is a serious medical condition because the clot can break loose, travel through the bloodstream, and lodge in the lungs, causing a potentially fatal pulmonary embolism (PE). Together, DVT and PE are known as venous thromboembolism (VTE).

An estimated 900,000 people in the United States develop VTE each year, and approximately 100,000 die from the condition annually.

DVT occurs when blood flow slows down, the vein lining is damaged, or the blood becomes more prone to clotting. Risk factors include:

• Surgery (especially hip/knee replacement, abdominal surgery)
• Prolonged immobility (long flights, bed rest, hospitalization)
• Cancer and cancer treatment
• Pregnancy and the postpartum period
• Oral contraceptives or hormone replacement therapy
• Obesity
• Smoking
• Age over 60
• Personal or family history of DVT/PE
• Inherited clotting disorders (Factor V Leiden, prothrombin gene mutation)
• Central venous catheters
• Heart failure
• Inflammatory bowel disease

About half of DVT cases produce no noticeable symptoms. When symptoms occur, they typically affect one leg and include:

• Swelling in the affected leg (sometimes the entire leg)
• Pain or tenderness, often starting in the calf and feeling like cramping or soreness
• Red or discolored skin on the leg
• Warmth in the affected area
• Enlarged surface veins

• D-dimer blood test: Elevated levels suggest active clot formation (high sensitivity but low specificity)
• Duplex ultrasonography: The primary imaging test -- uses sound waves to detect blood clots in veins (sensitivity >95%)
• CT venography or MRI venography: Used when ultrasound is inconclusive
• Wells score: Clinical prediction tool that combines symptoms, risk factors, and examination findings to estimate DVT probability

Anticoagulation (blood thinners) -- the primary treatment:

• Direct oral anticoagulants (DOACs) such as rivaroxaban or apixaban are now first-line for most patients
• Low-molecular-weight heparin (LMWH) such as enoxaparin, followed by warfarin, is an alternative
• Treatment duration: 3 months minimum for provoked DVT; extended or indefinite for unprovoked or recurrent DVT

Additional treatments:

• Compression stockings: May help reduce post-thrombotic syndrome symptoms
• Thrombolysis: Clot-dissolving drugs for massive or limb-threatening DVT
• Thrombectomy: Surgical clot removal in severe cases
• IVC filter: Placed in the inferior vena cava to catch clots if anticoagulation is contraindicated

Self-care during treatment:

• Stay active and walk regularly (bed rest is no longer recommended)
• Elevate the affected leg when resting
• Stay hydrated
• Attend all follow-up appointments
• Be aware of bleeding signs while on anticoagulants

• Move and stretch during long trips (get up every 1-2 hours)
• Stay active after surgery as early as permitted
• Use compression stockings if recommended
• Stay hydrated
• Take prescribed blood thinners before and after surgery if indicated
• Maintain a healthy weight
• Do not smoke

See a doctor promptly if you notice swelling, pain, or redness in one leg that develops over hours to days. Go to the emergency room if you develop sudden shortness of breath, chest pain, or cough up blood.