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CardiovascularICD-10: I82.90Up to 900,000 VTE events occur annually in the U.S.

Blood Clots

Also known as: Thrombosis, Thrombus, Venous Thromboembolism, VTE

Blood clots are gel-like clumps of blood that form in veins or arteries, potentially blocking blood flow. While clotting is essential for stopping bleeding from wounds, abnormal clots inside blood vessels can be life-threatening if they block blood flow to the lungs (pulmonary embolism), brain (stroke), or heart. Prompt diagnosis and anticoagulant therapy are critical to prevent serious complications.

Symptoms

Swelling in one leg or arm
Pain or tenderness, often starting in the calf
Red or discolored skin over the affected area
Warmth in the swollen limb
Sudden shortness of breath (if clot reaches the lungs)
Chest pain that worsens with deep breathing
Rapid heartbeat
Coughing up blood (in pulmonary embolism)

Causes

  • Prolonged immobility (long flights, bed rest, hospitalization)
  • Damage to blood vessel walls from surgery or injury
  • Blood clotting disorders (Factor V Leiden, antiphospholipid syndrome)
  • Hormonal factors (oral contraceptives, hormone replacement therapy)

Risk Factors

  • Recent surgery or hospitalization
  • Prolonged immobility or travel
  • Cancer and cancer treatment
  • Pregnancy and postpartum period
  • Obesity
  • Smoking

Diagnosis

  • D-dimer blood test (elevated levels suggest clotting)
  • Duplex ultrasound of affected limb for DVT
  • CT pulmonary angiography (CTPA) for pulmonary embolism
  • Venography (rarely used, gold standard for DVT)
  • Blood tests for clotting disorders if recurrent

Treatment

  • Anticoagulant medications (heparin, warfarin, DOACs like rivaroxaban)
  • Thrombolytic therapy (clot-busting drugs) for life-threatening clots
  • Inferior vena cava (IVC) filter for patients who cannot take anticoagulants
  • Compression stockings to reduce swelling and prevent post-thrombotic syndrome
  • Catheter-directed thrombolysis for large clots

Prevention

  • Move and stretch regularly during long trips or periods of immobility
  • Stay hydrated and avoid excessive alcohol
  • Wear compression stockings if at risk
  • Take prescribed blood thinners after surgery as directed
  • Maintain a healthy weight and stay physically active

When to See a Doctor

  • You develop sudden swelling, pain, or redness in one leg
  • You experience sudden shortness of breath or chest pain—call 911
  • You cough up blood or feel faint with rapid heartbeat—seek emergency care
  • You have a known clotting disorder and develop new symptoms

Frequently Asked Questions

Related Conditions

Deep Vein Thrombosis

Cardiovascular

Atrial Fibrillation

Cardiovascular

Coronary Artery Disease

Cardiovascular

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Medical Disclaimer: This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.

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