Blood clots: What you should know about symptoms and risks

Blood clots can affect anyone, including young, healthy adults and professional athletes. The recent news surrounding Philadelphia Eagles quarterback Jalen Hurts has brought attention to the potentially life-threatening condition and the importance of recognizing its warning signs.

On Oct. 19, the Eagles and Hurts' agent announced that the 28-year-old quarterback had been diagnosed with deep vein thrombosis (DVT)—a blood clot in a vein deep inside the body—and bilateral pulmonary emboli, meaning blood clots were found in both lungs. Hurts was initially diagnosed with superficial vein thrombosis, a clot in a vein just under the skin in his left calf, but further testing revealed the more serious conditions.

According to the team's statement, Hurts is in stable condition and expected to make a full recovery. He will be treated with anticoagulants—commonly called blood thinners—and cannot participate in contact sports, including football, while taking the medication.

While blood clotting is a normal process that helps the body stop bleeding after an injury, clots that develop inside blood vessels can block blood flow and lead to serious complications. And although certain factors—including surgery, prolonged inactivity and certain health conditions—can raise the risk, being physically fit does not eliminate that risk.

Aditya Sharma, MD, is medical director at the Vascular Medicine & Venous Thromboembolism Center of Excellence and a vascular medicine physician at Atrium Health Sanger Heart & Vascular Institute, in Charlotte, North Carolina, which is part of Advocate Health. Dr. Sharma explained what people should know about blood clots, from recognizing symptoms and understanding risk factors to preventing and treating the condition.

Advocate Health is part of the AMA Health System Member Program, which provides enterprise solutions to equip leadership, physicians and care teams with resources to help drive the future of medicine.

Understand the different types of blood clots

“Normally, blood flows freely through our blood vessels—our veins and arteries. When parts of the blood clump that becomes a clot,” Dr. Sharma explained. 

But not all blood clots are the same. Where a blood clot forms can determine how dangerous it is and what treatment may be needed. For instance, superficial vein thrombosis occurs when a blood clot forms in a vein close to the skin's surface. These veins carry blood into deeper veins, which transport blood back toward the heart and lungs. 

“Superficial veins are sometimes the veins we can actually see on our arms and legs," Dr. Sharma said. “They first drain into the deep veins, so they don’t connect as directly to the heart and lungs as the deep veins do."

Deep vein thrombosis occurs when a clot forms in one of the body's deeper veins, most often in the legs. Because these veins lead directly to the heart and lungs, part of a clot can break off and travel through the bloodstream. That can lead to a pulmonary embolism, which occurs when a clot travels to the lungs and blocks a blood vessel there. A pulmonary embolism can prevent blood from flowing normally through the lungs, make it harder for the body to get oxygen, and, in severe cases, can be life-threatening. 

Understanding these differences is important because symptoms and the urgency of treatment can vary depending on where the clot develops. Clots in veins near the skin are usually less dangerous, but they can sometimes extend into the deep veins or occur alongside a deeper clot, so they should still be checked by a doctor.

Recognize the warning signs of blood clots

One challenge with identifying blood clots is that their symptoms can resemble other, less serious conditions.

"The symptoms for a blood clot in the legs can very well mimic symptoms of a muscle strain or leg cramps," Dr. Sharma said, noting that people with deep vein thrombosis may have aching, sharp or dull pain in the calf, thigh or entire leg. Swelling may also develop, usually in just one leg.

With superficial vein thrombosis, people may notice a red, tender, rope-like cord under the skin that can be painful to touch. 

“If you touch it, it’ll hurt a lot, especially early on when the vein is inflamed,” he noted. 

Symptoms of a pulmonary embolism can be different and may resemble those of a heart attack. These include chest pain that may get worse with a deep breath, shortness of breath, a racing heartbeat, lightheadedness and fainting. Some people may also cough up blood. Recognizing these symptoms and getting help right away is critical.

New, unexplained pain, swelling or a change in skin color in one leg or arm should be checked by a doctor promptly as well. Symptoms that suggest a pulmonary embolism—including sudden shortness of breath, chest pain or fainting—require emergency care. Call 911 or go to the nearest emergency department.

A pulmonary embolism can become life-threatening quickly, making it important not to delay treatment.

Know who is at risk for blood clots

Although the risk of developing blood clots generally rises with age, they can occur in people of all ages and fitness levels.

“Being active and healthy doesn’t make us completely immune to blood clots,” Dr. Sharma said.

Certain medical conditions and circumstances can raise the risk of developing a blood clot. These include:

• Recent surgery or hospitalization. Spending extended periods in bed, recovering from surgery or experiencing a severe illness can raise the risk.
• Prolonged inactivity. Long flights, car rides or periods of limited mobility can slow blood flow, making clots more likely.
• Cancer. Certain cancers and some cancer treatments can make blood more likely to clot.
• Pregnancy and hormone therapy. Pregnancy, the weeks after giving birth and medications that contain estrogen—such as some birth control pills and hormone therapy for menopause—can raise the risk.
• Family or personal history. People who have had a blood clot before, or who have close relatives who have had clots, may face a higher risk.
• Obesity. Higher body weight is another factor associated with a greater risk of blood clots.

"Patients are at very high risk of getting blood clots in that immediate period after surgery, immediate period after hospitalization, immediate period after severe illness," Dr. Sharma said, noting that wearing a cast or walking boot, undergoing surgery after an injury or direct damage to a vein can also raise the risk.

“For women specifically, another risk is pregnancy and the weeks right after giving birth,” he added. “Hormone therapy can also raise the risk, especially therapy that contains estrogen.”

Even athletes can develop blood clots, particularly following injuries that limit movement. 

"Often, we think if we are active, we are fit, we are healthy, that we are unlikely to have any medical problems," Dr. Sharma said. 

Certain athletes, including swimmers, weightlifters and those who perform repetitive overhead movements, may develop blood clots in the arms. That is because repeated arm movements can squeeze a large vein near the collarbone and slow normal blood flow.

Take steps to lower your blood-clot risk

Although not all blood clots can be prevented, several everyday habits can help lower the risk. One of the most important is avoiding prolonged periods of inactivity.

"During long flights or long drives, getting up and walking every hour or two is great," Dr. Sharma said.

For people who cannot easily stand or walk, simple ankle movements can help keep blood circulating. Flexing the ankles up and down, sometimes called calf pumps, is one way to encourage blood flow while seated. 

Compression stockings may also be helpful during extended travel, but whether you need them depends on your own risk, so ask your doctor. Drinking enough fluids is also a good idea, particularly during travel or physical activity.

Additionally, for people recovering from surgery or hospitalization, prevention may require additional steps.

"After surgery or after a hospital stay, you could certainly be at increased risk, and this is where working with your doctors comes in," Dr. Sharma said, encouraging people to ask their doctor about their blood clot risk before and after surgery.

Depending on the circumstances, doctors may recommend a blood thinner to help prevent clots, or leg sleeves that gently squeeze and release to keep blood moving.

Maintaining regular physical activity and managing other health conditions can also play a role in lowering risk.

Understand how blood clots are treated

When a blood clot is diagnosed, treatment depends on its location, severity and the person’s overall health.

“The main treatment for almost every blood clot is a blood thinner,” Dr. Sharma said, explaining that blood thinners don’t dissolve the clot. Instead, they help keep it from growing and stop new clots from forming while the body gradually breaks down the old clot on its own.

In more serious cases, doctors may use clot-dissolving medications or minimally invasive procedures, in which a thin, flexible tube is threaded through a blood vessel to remove or break up the clot. Some people with severe pulmonary embolism may require surgery or other advanced treatments.

Most people take blood thinners for at least three months. Some need longer treatment, sometimes for the rest of their lives, depending on what caused the clot and their risk of developing another one. Ultimately, while some people may recover relatively quickly, others experience lingering symptoms.

After a deep vein clot, some people have lasting swelling, discomfort or changes in skin color in the affected arm or leg. Those recovering from a pulmonary embolism may feel tired or short of breath, which often improves with time.

The experience can also take an emotional toll, particularly for people who worry about another clot developing.

Understanding the recovery process and maintaining follow-up care can help people manage symptoms and talk with their doctor about their risk of another clot.

Don’t hesitate to seek medical care 

Knowing the warning signs of blood clots can make a difference in recognizing a potentially dangerous condition.

Dr. Sharma encourages people to pay attention to changes in their bodies and ask questions when something does not feel right.

“Trust your instincts, trust your body,” he said. "If you feel something's wrong with these kinds of symptoms ... there's nothing wrong with asking, ‘Could I have a blood clot’?"

Anyone with new, unexplained swelling or pain in an arm or leg should see a doctor promptly. Sudden shortness of breath, chest pain, fainting or other symptoms of a pulmonary embolism require immediate emergency care—call 911.

"It is a very common condition. It's important to know about it just like how you would know about heart attacks and strokes," Dr. Sharma said, emphasizing that understanding blood-clot symptoms and risk factors is an important part of protecting your health.