Deep Venous Thrombosis: Symptoms and Risk Factors

Deep venous thrombosis (DVT) is a common medical syndrome that affects 600,000 individuals per year. It is associated with blood clots that form in the extremities. Although it is most often found in the legs, DVT can also occur in the upper extremities, especially in hospitalized patients with indwelling central venous catheters.

In itself, DVT is often asymptomatic. However, pulmonary embolism is a feared complication of DVT, and one of the leading preventible causes of death in hospitals. Pulmonary embolism occurs when a blood clot travels from the extremity, through the bloodstream, and to the lung. Once there, the clot can choke off the blood supply to the lung and may result in life–threatening lung and heart diseases.

Symptoms

• Although most cases of DVT are asymptomatic, some patients may experience swelling, tenderness, warmth, and redness of the affected limb.
  
• Symptoms of pulmonary embolism may include shortness of breath, sharp chest pain, and coughing up blood.

Risk Factors

• Prior DVT or pulmonary embolism: These are the strongest indicators of risk.
• Age: Risk increases with age. This is due in part to the greater likelihood of comorbid illness as one gets older.
• Surgery: Major procedures (e.g., orthopedic, thoracic, abdominal, and genitourinary) pose the greatest risk.
• Trauma: Examples include fracture of the spine, pelvis, femur, or tibia.
• Disorders of blood clotting: These include protein C and S deficiencies, antithrombin III deficiency, and factor V Leiden.
• Prolonged immobilization: Examples include extended air travel, post–surgery, inability to walk (e.g., bedridden patients).
• Oral contraceptives and hormone replacement therapy: Oral contraceptive use is especially dangerous in women older than 35 years who are smokers.
• Additional risk factors include pregnancy, obesity, elevated cholesterol levels, and cancer.