Anyone can be affected by a blood clot regardless of age, gender, or race. Learn about the signs and symptoms of a blood clot and what you can do to help prevent one.  

What is a blood clot?

A deep vein thrombosis (DVT) is when a blood clot forms in one of the large veins, usually in the lower leg, thigh, pelvis, or arm. A blood clot can partially or completely block blood flow in the vein. When a DVT is left untreated, a part of the clot can break off and travel to the lungs, causing a blockage known as a pulmonary embolism (PE).

Why is it important to learn about blood clots?

In the United States, an estimated 900,000 people are affected by a blood clot every year, yet they are often underdiagnosed. Blood clots can cause serious medical conditions that can lead to illness, disability, and even death if not treated early. Blood clots can affect anyone, but certain risk factors such as pregnancy, cancer and its treatment, and hospitalization can increase a person’s risk for a blood clot. It’s important to know the signs and symptoms of a blood clot so that you know to seek medical treatment as early as possible.

Knowing the symptoms of a DVT or PE can help alert you to seek medical treatment as early as possible, although they sometimes occur with no symptoms.

Common signs and symptoms of a DVT include:

• Swelling of the affected area
• Pain
• Tenderness
• Redness of the skin

If you have these signs or symptoms, alert your doctor as soon as possible.

Common signs and symptoms of a PE include:

• Difficulty breathing
• Faster than normal or irregular heartbeat
• Coughing up blood
• Very low blood pressure, lightheadedness, or fainting

Seek medical attention immediately if you experience any of these signs or symptoms.

What is a blood clot?

A blood clot is mass of blood that forms when platelets, proteins, and cells in the blood stick together. When you get hurt, your body forms a blood clot to stop the bleeding. After the bleeding stops and healing takes place, your body usually breaks down and removes the blood clot. But sometimes the blood clots form where they shouldn't, your body makes too many blood clots or abnormal blood clots, or the blood clots don't break down like they should. These blood clots can be dangerous and may cause other health problems.

Blood clots can form in, or travel to, the blood vessels in the limbs, lungs, brain, heart, and kidneys. The types of problems blood clots can cause will depend on where they are:

• Deep vein thrombosis (DVT) is a blood clot in a deep vein, usually in the lower leg, thigh, or pelvis. It can block a vein and cause damage to your leg.
• A pulmonary embolism can happen when a DVT breaks off and travels through the bloodstream to the lungs. It can damage your lungs and prevent your other organs from getting enough oxygen.
• Cerebral venous sinus thrombosis (CVST) is a rare blood clot in the venous sinuses in your brain. Normally the venous sinuses drain blood from your brain. CVST blocks the blood from draining and can cause a hemorrhagic stroke.
• Blood clots in other parts of the body can cause problems such as an ischemic stroke, a heart attack, kidney problems, kidney failure, and pregnancy-related problems.

Who is at risk for blood clots?

Certain factors can raise the risk of blood clots:

• Atherosclerosis
• Atrial fibrillation
• Cancer and cancer treatments
• Certain genetic disorders
• Certain surgeries
• COVID-19
• Diabetes
• Family history of blood clots
• Overweight and obesity
• Pregnancy and giving birth
• Serious injuries
• Some medicines, including birth control pills
• Smoking
• Staying in one position for a long time, such as being in the hospital or taking a long car or plane ride

What are the symptoms of blood clots?

The symptoms for blood clots can be different, depending on where the blood clot is:

• In the abdomen: Abdominal pain, nausea and vomiting
• In an arm or leg: Sudden or gradual pain, swelling, tenderness, and warmth
• In the lungs: Shortness of breath, pain with deep breathing, rapid breathing, and increased heart rate
• In the brain: Trouble speaking, vision problems, seizures, weakness on one side of the body, and sudden severe headache
• In the heart: Chest pain, sweating, shortness of breath, and pain in the left arm

How are blood clots diagnosed?

Your health care provider may use many tools to diagnose blood clots:

• A physical exam
• A medical history
• Blood tests, including a D-dimer test
• Imaging tests, such as
  • Ultrasound
  • X-rays of the veins (venography) or blood vessels (angiography) that are taken after you get an injection of special dye. The dye shows up on the x-ray and allows the provider to see how the blood flows.
  • CT Scan

What are the treatments for blood clots?

Treatments for blood clots depend on where the blood clot is located and how severe it is. Treatments may include:

• Blood thinners
• Other medicines, including thrombolytics. Thrombolytics are medicines which dissolve blood clots. They are usually used where the blood clots are severe.
• Surgery and other procedures to remove the blood clots

Can blood clots be prevented?

You may be able to help prevent blood clots by:

• Moving around as soon as possible after having been confined to your bed, such as after surgery, illness, or injury
• Getting up and moving around every few hours when you have to sit for long periods of time, for example if you are on a long flight or car trip
• Regular physical activity
• Not smoking
• Staying at a healthy weight

Some people at high risk may need to take blood thinners to prevent blood clots.

Blood clots normally form in response to an injury to a blood vessel, and they can develop in any part of the cardiovascular system. Blood clots are composed primarily of platelets (cell fragments in the blood that assist in clotting) and fibrin (an insoluble protein fiber formed as part of the clotting process). They may contain red blood cells as well.

Thrombi

A thrombus is a blood clot that adheres to the site of its formation, in the lumen (interior) of a blood vessel or in the heart. (Thrombus and the prefix thrombo- come from the Greek word thrombos, meaning a lump or clump.) Most of the time thrombi dissolve naturally and cause no problems. However, when they don't, they can partially block blood flow in a large blood vessel or block it completely in a smaller blood vessel. This may result in tissue death, as the flow of oxygenated blood is cut off.

Thromboembolisms

Thromboembolisms are the most common type of embolism. They are thrombi that break loose and are carried by the blood stream until they become lodged in a blood vessel, usually at a point where the vessel forks. The thromboembolism may plug a vessel in the lungs, causing a pulmonary embolism; the brain, causing a stroke; the heart, causing a heart attack; or the gastrointestinal tract, kidneys, or leg. In rare instances, other substances, such as a globule of fat, air bubbles, tissue from a tumor, or a clump of bacteria, may travel through the bloodstream as emboli and become lodged in an artery.

The majority of thrombi form in the veins, generally in the lower limbs. Arterial thrombi usually occur in people who have vascular (blood vessel) disease, commonly atherosclerosis. Thrombi may also form inside of the heart.

Venous thromboembolism (VTE), also known as blood clots, is a serious, growing public health issue that everyone should know about. Blood clots are preventable, yet an estimated 900,000 Americans are affected each year by a blood clot, resulting in nearly 100,000 deaths.

It is important to understand your risk for a blood clot and to know the signs and symptoms in order to seek treatment early and prevent death from a blood clot.

What is a blood clot?

A deep vein thrombosis (DVT) is a blood clot that occurs in a deep vein, usually in the lower leg, thigh, pelvis, or arm. A DVT can occur without any symptoms, but it is often accompanied by swelling, pain, and redness of the skin. If a DVT is not treated, a part of the clot can break off and travel to the lungs, causing a blockage in the lungs called a pulmonary embolism (PE). A PE can cause symptoms such as chest pain, difficulty breathing, coughing, coughing up blood, and irregular heartbeats. It is important to seek immediate medical treatment when experiencing any of these symptoms. A DVT does not go away on its own. Only a healthcare provider can diagnose and treat a blood clot with medicine or in rare cases, surgery.

Who is at risk for a blood clot?

Blood clots can affect anyone at any age, but certain risk factors, such as surgery, hospitalization, pregnancy, cancer and some types of cancer treatments can increase risks. In addition, a family history of blood clots can increase a person’s risk. The chance of a blood clot increases when you have more risk factors.

Why is there limited awareness about blood clots?

Many people do not know much about blood clots and are not familiar with the signs and symptoms until it happens to them or someone they know. In addition, the signs and symptoms of a DVT and PE are similar to other health problems and can be misdiagnosed as other health conditions. A misdiagnosis can lead to delayed treatment of a DVT, resulting in a PE or even death.  Understanding your risk for a blood clot and the signs and symptoms can help you seek treatment at the earliest sign of a blood clot to protect your health.

Blood clots can form if you don't move around a lot. You may also get a blood clot if you:

• Have had recent surgery.
• Are 65 or older.
• Take hormones, especially for birth control. (Ask your doctor about this).
• Have had cancer or are being treated for it.
• Have broken a bone (hip, pelvis, or leg).
• Have a bad bump or bruise.
• Are obese.
• Are confined to bed or a chair much of the time.
• Have had a stroke or are paralyzed.
• Have a special port the doctor put in your body to give you medicine.
• Have varicose (VAR-e-kos) or bad veins.
• Have heart trouble.
• Have had a blood clot before.
• Have a family member who has had a blood clot.
• Have taken a long trip (more than an hour) in a car, airplane, bus, or train.

Are you at risk?

Some people are more likely to get blood clots. Talk with your doctor to see if you are at risk.

You may have a blood clot if you see or feel:

• New swelling in your arm or leg.
• Skin redness.
• Soreness or pain in your arm or leg.
• A warm spot on your leg.

Important!

If you think you have a blood clot, call your doctor or go to the emergency room right away!

Blood clots can be dangerous. Blood clots that form in the veins in your legs, arms, and groin can break loose and move to other parts of your body, including your lungs. A blood clot in your lungs is called a pulmonary embolism (POOL-mo-nar-e EM-bo-liz-em). If this happens, your life can be in danger. Go to the emergency room or call 911.

A blood clot may have gone to your lungs if you suddenly have:

• A hard time breathing.
• Chest pain.
• A fast heartbeat.
• Fainting spells.
• A mild fever.
• A cough, with or without blood.

Your health care provider may use many tools to diagnose blood clots:

• A physical exam
• A medical history
• Blood tests, including a D-dimer test
• Imaging tests, such as
  • Ultrasound
  • X-rays of the veins (venography) or blood vessels (angiography) that are taken after you get an injection of special dye. The dye shows up on the x-ray and allows the provider to see how the blood flows.
  • CT Scan

If you have been told you have a blood clot, your doctor may give you medicine to treat it. This type of medicine is called a blood thinner (also called an anticoagulant [an-te-ko-AG-u-lent]). In most cases, your doctor will tell you to follow this treatment plan:

• For the first week you will receive medicine called heparin (HEP-a-rin) that works quickly.

• This medicine is injected under the skin. You will learn how to give yourself these shots, or a family member or friend may do it for you.

• You will also start taking Coumadin® (COO-ma-din)—generic name: warfarin (WAR-far-in)—pills by mouth. After about a week of taking both the shots and the pills, you will stop taking the shots. You will continue to take the Coumadin®/warfarin pills for about 3 to 6 months or longer.

Side Effects of Blood Thinners

Blood thinners can cause side effects. Bleeding is the most common problem. Your doctor will watch you closely. If you notice something wrong that you think may be caused by your medication, call your doctor.

Are you bleeding too much?

If you think you are bleeding too much, call your doctor or go to the nearest emergency room. Tell them you are being treated for blood clots. Tell them the medicines you are taking.

You can help prevent blood clots if you:

• Wear loose-fitting clothes, socks, or stockings.
• Raise your legs 6 inches above your heart from time to time.
• Wear special stockings (called compression stockings) if your doctor prescribes them.
• Do exercises your doctor gives you.
• Change your position often, especially during a long trip.
• Do not stand or sit for more than 1 hour at a time.
• Eat less salt.
• Try not to bump or hurt your legs and try not to cross them.
• Do not use pillows under your knees.
• Raise the bottom of your bed 4 to 6 inches with blocks or books.
• Take all medicines the doctor prescribes you.

Stay active!

Staying active and moving around may help prevent blood clots.

Deep vein thrombosis (DVT) is a blood clot that forms in a vein deep in the body. Blood clots happen when blood thickens and clumps together.

“Only about half of the people who have DVT have signs and symptoms.”

— Andrei Kindzelski, M.D., Ph.D., Program Director in the Division of Blood Diseases and Resources at the National Heart, Lung, and Blood Institute

Clots can cause symptoms like swelling, discomfort, cramps, and redness or discoloration on the leg. But many cases—up to 50 percent— may go unnoticed. In fact, some people may not realize they have a clot or symptoms of a clot until it develops into something more serious.

Blood clots most often happen in the veins, instead of the arteries, because blood travels slower than in the arteries. However, blood clots in the arteries can also happen.

Most deep vein blood clots happen in the lower leg or thigh. This is because blood pressure in our veins is lower in the areas of the body that are farther away from the heart. So, our leg veins are more susceptible to situations where blood flow can be interrupted.

Some blood clots can break off and travel through the bloodstream. This loose clot is called an embolus.

An embolus can be very dangerous. Sometimes they travel to an artery in the lungs and block blood flow. That creates what’s called a pulmonary embolism (PE). A PE can damage the lungs and other organs in the body and cause death.

While DVT and PE can affect anyone, your risk of a blood clot is higher if you’ve been traveling for long periods of time, have been ill and in bed for a while, or have had surgery. Chronic heart conditions, cancer, stroke, and paralysis (not being able to move) can also increase your chances of getting a clot.