Deep Vein Thrombosis

Deep Vein Thrombosis is a blood clot in a vein deep within the body. Veins are blood vessels. The muscles in the arms and legs contract and help force the blood through the veins back to the heart. A system of valves within the veins helps prevent the blood from flowing backwards. Deposits of red blood cells and clotting elements in the blood can accumulate in a vein and lead to blood clot formation. Clots usually occur in the legs but can occur in other locations. As the clot grows, it blocks blood flow in the affected vein.

Causes

Several factors contribute to clot formation, including:
  • Slow blood flow, often due to lying or sitting still for an extended period of time
  • Pooling of blood in a vein, often due to:
    • Immobility
    • Medical conditions
    • Damage to valves in a vein or pressure on the valves, such as occurs during pregnancy
  • Injury to a blood vessel
  • Clotting problems (can occur due to aging or disease)
  • Catheters placed in a vein

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition.
  • Not moving your body
  • Hospitalization
  • Surgery, especially involving bones or joints
  • Medical conditions such as:
    • Varicose veins
    • Cancer
    • Heart failure
    • Heart attack
    • Inflammatory bowel disease
    • Blood disorders
  • Obesity
  • History of deep vein thrombosis
  • Taking birth control pills or estrogen therapy
  • Pregnancy

Symptoms

Symptoms occur when:
  • The clot interferes with blood flow in the vein; or
  • Local inflammation occurs; or
  • A clot breaks free and travels to the lungs
Some patients may not experience any symptoms until the clot moves to the lungs, a condition called pulmonary embolism. Symptoms of deep vein thrombosis may include:
  • Pain
  • Swelling of a limb
  • Tenderness along the vein
  • Warmth
  • Redness, paleness or blueness of the skin of the affected limb

Diagnosis

The doctor will ask about your symptoms and medical history, and perform a physical exam.

Tests may include:

Duplex Venous Ultrasound – a test that uses sound waves to detect changes in blood flow

Venography – x-rays taken after dye is injected into a small vein, to show areas of normal and abnormal blood flow

Impedance Plethysmography – measures changes in blood volume in the veins as a blood pressure cuff wrapped around the thigh is inflated and deflated

Diagnosis

The doctor will examine your skin lesions and ask about your symptoms and medical history. Initial diagnosis is based on the appearance of your skin lesions. If you have impetigo, a culture of the skin lesion, if done, may show streptococcus or staphylococcus. A culture is usually not necessary except in severe or persistent infections.

Treatment

Treatment aims to:
  • Prevent pulmonary embolism
  • Stop the clot from growing
  • Dissolve the clot (sometimes)

Treatments include:

Supportive Care
 
This may include:

  • Resting in bed
  • Elevating the affected limb above the heart
  • Wearing compression stockings as recommended by your doctor

Medications

Anticoagulant drugs to prevent additional clot formation include:

  • Heparin injection – fast-acting drug that prevents more clot formation (given for several days)
  • Warfarin (taken by mouth) – slowly prevents more clot formation (usually given for several months)
  • Fibrinolytic enzymes – to help dissolve a major clot. These include:
    • Streptokinase
    • Urokinase
    • TPA
Surgery
In certain situations, doctors may place a filter in the inferior vena cava, a major vein returning blood from the lower body to the heart. The filter may trap any clots that break loose and travel toward the lungs.

Prevention

General prevention measures include:
  • Not sitting for long periods in a car or airplane (Get up frequently and move around.)
  • Not smoking
If you are admitted to the hospital, talk to your doctor about how to prevent blood clots, such as:
  • Getting out of bed and walking as soon as possible during your recovery
  • If you are restricted to bed:
    • Doing range of motion exercises in bed
    • Changing your position at least every two hours
  • Wearing compression stockings, which promotes venous blood flow
  • Taking anticoagulant medication if advised by your doctor
  • Using a pneumatic compression device – a device that uses air to compress your legs and help improve venous blood flow