Blood Clot in the Legs (cont.)
Signs and Symptoms of DVT
Signs and symptoms of a blood clot in the leg or deep vein thrombosis occur in the affected leg when a clot obstructs blood flow and causes inflammation. Signs and symptoms of DVT may include:
- Gradual onset of pain
- Warmth to the touch
- Worsening leg pain when bending the foot
- Leg cramps, especially at night, and often starting in the calf
- Bluish or whitish discoloration of skin
Some people with deep vein thrombosis do not experience any symptoms.
What Causes a Blood Clot In the Leg?
Three factors may lead to formation of a clot inside a blood vessel:
- Damage to the inside of a blood vessel due to trauma or other conditions
- Changes in normal blood flow, including unusual turbulence, or partial or complete blockage of blood flow
- Hypercoagulability, a rare state in which the blood is more likely than usual to clot
Any event or condition that can lead to blood vessel damage, hypercoagulability, or change in blood flow can potentially cause deep vein thrombosis. The more common risk factors are:
- Prolonged sitting, such as during a long plane flight or car ride
- Prolonged bed rest or immobility, such as after injury or during illness (for example stroke)
- Recent surgery, particularly orthopedic (especially hip, leg, or , knee such as knee or hip replacement), gynecologic, heart, or abdominal surgery
- Recent trauma to the lower body, such as fractures of the bones of the hip, thigh, or lower leg
- Heart attack or heart failure
- Pregnancy or recent childbirth
- Being at very high altitude, greater than 14,000 feet
- Use of estrogen therapy or birth control pills
- Rare inherited genetic conditions that lead to changes in certain blood clotting factors
- Certain heart or respiratory conditions
- Advanced age
- Medical conditions that affect the veins such as vasculitis (inflammation of the vein walls), varicose veins
- Superficial venous thrombosis (SVT) occurs when a blood clot forms in a superficial vein near the surface of the body. While not the same as DVT (which occurs in deep veins) it can be a risk factor for DVT/PE
- Disseminated intravascular coagulation (DIC), a medical condition in which blood clotting occurs inappropriately, usually is caused by overwhelming infection or organ failure
If an individual has one deep vein thrombosis, they are 33% more likely to develop a second deep vein thrombosis within 10 years.
When To Seek Medical Care for a Blood Clot In the Leg
Call the doctor immediately if a blood clot is suspected.
- Although a deep vein thrombosis may resolve on its own, the life-threatening consequences of a clot reaching the lung, called pulmonary embolism, are severe enough to warrant seeking medical attention immediately.
- The doctor may tell the patient to go immediately to a hospital emergency department.
If a person has leg pain or swelling with any risk factors, go to a hospital emergency department immediately.
Call 9-1-1 if you or someone you know with a current deep vein thrombosis, previous deep vein thrombosis, or other DVT/PE risk factor begins having chest pain, shortness of breath, difficulty breathing, fainting, or any other concerning symptom.
How Do Doctors Diagnose DVT?
Upon hearing the patient's symptoms, the doctor may suspect the patient has a deep vein thrombosis, especially if any risk factors are present.
No accurate blood test is available to diagnose deep vein thrombosis. A variety of imaging tests are used to confirm the diagnosis.
- Doppler ultrasound: Using high-frequency sound waves, this system can visualize the large, proximal veins and detect a clot if one is present. Painless and without complications, this is the most commonly used method to diagnose deep vein thrombosis. However, sometimes the test can miss a clot, especially in the smaller veins.
- Venography: A liquid dye is injected into the veins for imaging studies. It highlights blockage of blood flow by a clot. This is the most accurate test, but also the most uncomfortable and invasive. It is rarely done today because of the availability of improved ultrasound technology.
- Impedance plethysmography: Electrodes are used to measure volume changes within veins. Because this test does not detect clots better than ultrasound and is harder to perform, it is rarely used.
- CT scan: This is a type of X-ray that gives a very detailed look at the leg veins in cross section and can detect clots. It is rarely used for this purpose as it is more difficult to interpret and is time consuming. The CT scan is more useful for identification of blood clots in the lung.
Medically Reviewed by a Doctor on 9/11/2017
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