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Medical Author:

Benjamin Wedro, MD, FACEP, FAAEM

Benjamin Wedro, MD, FACEP, FAAEM

Dr. Ben Wedro practices emergency medicine at Gundersen Clinic, a regional trauma center in La Crosse, Wisconsin. His background includes undergraduate and medical studies at the University of Alberta, a Family Practice internship at Queen's University in Kingston, Ontario and residency training in Emergency Medicine at the University of Oklahoma Health Sciences Center.

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Medical Editor:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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In this Article

• Blood clot facts
• What are blood clots?
• What causes blood clots?
• What does a blood clot look like?
• What are the risk factors for blood clots?
• What types and conditions are caused by blood clots?
• What are the symptoms of blood clots?
• How are blood clots diagnosed?
• What is the treatment for blood clots?
• What are the complications of blood clots?
• How can blood clots be prevented?
• Patient Comments: Blood Clots - Causes
• Patient Comments: Blood Clots - Symptoms
• Patient Comments: Blood Clots - Describe Your Experience
• Blood Clots Index

Depending upon their location, blood clots may be aggressively treated or may need nothing more than symptomatic care.

Venous blood clots

Venous thrombosis in the leg may occur in the superficial or deep systems of veins.

Clots in the superficial system are often treated symptomatically with warm compresses and acetaminophen or ibuprofen since there is no risk for clots in the superficial veins to embolize to the lung. They are connected to the deep system by perforator veins that have valves that act like a sieve to strain and prevent any clots form getting to the lung.

Deep venous thrombosis usually requires anticoagulation to prevent the clot from growing and causing a pulmonary embolus. Initial therapy with injectable enoxaparin (Lovenox) is used to immediately "thin" the blood. Meanwhile, warfarin (Coumadin) is prescribed as an anti-coagulation pill. It takes a few days for warfarin to reach therapeutic levels and in this time frame, both the injectable and oral medications are used. Most often, patients with DVTs are treated as an outpatient and taught how to give themselves enoxaparin (Lovenox) injections. Occasionally, depending upon circumstances, patients may be admitted to the hospital for an unfractionated heparin intravenous (IV) injection.

Blood clots below the knee are at lower risk for embolization to the lung, and an alternative to anti-coagulation treatment is serial ultrasound examinations to monitor the clot to see if it is growing or being resorbed by the body.

Pulmonary emboli are treated similarly to deep venous thrombosis, but depending on the severity of the symptoms, amount of clot formation, and the underlying health of the patient, admission to the hospital for treatment and observation may be needed. This is especially the case if lung function is compromised and the patient is short of breath or is experiencing hypoxia, or low oxygen levels in the blood.

Arterial blood clots

Arterial blood clots are often managed more aggressively. Surgery may be attempted to remove the clot, or medication may be administered directly into the clot to try to dissolve it. Alteplase (Activase, TPA) or tenecteplase (TNKase) are examples of medications that may be used in peripheral arteries to try to restore blood supply.

This is the same approach that is used for heart attack. If possible, cardiac catheterization is performed to locate the blocked blood vessel and a balloon is used to open the occluded area, restore blood flow, and place a stent to keep it open. This is a time-sensitive procedure and if a hospital is not available to do the procedure emergently, TPA or TNK is used intravenously to try to dissolve the thrombus and minimize heart damage.

Stroke is also treated with TPA if the patient is an appropriate candidate for this therapy.