After a two-month hiatus, Al Roker is back on air. In November 2022, the popular TODAY anchor was hospitalized due to deep vein thrombosis, which is when blood clots form in deep veins, usually in the lower leg, thigh, or pelvis. In a recent interview with TODAY, Roker revealed that the blood clots had developed after he had COVID-19 in the fall. The blood clots had started in his leg, but later moved into his lungs. He was also dealing with internal bleeding.
As a result, Roker said he lost half his blood and had to have multiple surgeries after his medical team at NewYork-Presbyterian/Weill Cornell Medical Center discovered two bleeding ulcers.
“The risk of [blood clots] has increased after infection with COVID because [COVID] leads to an inflammatory response in the body and promotes blood clotting,” explains Dr. Shruti Chaturvedi, an associate professor of medicine at Johns Hopkins Hospital.
Here’s what you need to know about blood clots, symptoms and causes.
What is a blood clot?
A blood clot is a gel-like clump of blood, which can protect you against bleeding out from an injury.
“Blood clots are a problem when they form not in response as a defense mechanism to an injury, but they’re found for no good reason and obstruct the flow of blood,” explains Chaturvedi.
A blood clot can form either in the vein, as is the case with deep vein thrombosis, or in arteries, where it’s most commonly found in the heart and brain and can cause heart attacks and strokes.
What are common symptoms of blood clots?
The most common symptoms of blood clots are swelling and discomfort in the legs. More often than not, swelling and tightness will appear on one side of the body, or one leg, and progress to pain.
“Some people will also see that the leg is progressively getting slightly swollen and larger than the other side and in very extreme cases, the leg can actually change color and become kind of reddish or bluish,” says Chaturvedi.
When should I see a doctor?
You should call your doctor right away if you’re experiencing swelling, redness, or pain in your arms or legs. If you’re experiencing shortness of breath, chest pain, a sudden change in vision, sudden numbness or difficulty speaking, you should visit urgent care or go to an emergency room immediately.
Upon arrival, your doctor may administer a D-dimer test, which is a blood test to determine whether you have a blood clotting condition.
“This is a screening test,” explains Chaturvedi. “If the D-dimer test is negative, the chance of having a blood clot is very, very low. It’s essentially a good way to rule things out, but if it’s positive it tells you it might be a blood clot. It might be a whole number of things.”
In order to definitively find a blood clot, your doctor may recommend imaging, such as a Doppler ultrasound of the leg. To look for blood clots in the lung, or a pulmonary embolism, your doctor would order a CT scan with contrast.
How are blood clots treated?
If it’s a venous blood clot, which forms in a deep vein, it can be treated with anticoagulants or injectable blood thinners. Once patients are clinically stable—meaning they are breathing on their own, their blood pressure is normal, and there are no other danger signs—they may be treated with oral anticoagulants such as Eliquis or Xarelto. But the most common side effect, Chaturvedi warns, is an increased risk of bleeding.
“When someone’s starting on medications like this, your doctor is probably going to ask you questions that try to assess what your risk of bleeding is,” she says. “These questions may include: 'Have you ever noticed blood in your bowel movements or urine? Have you ever coughed up blood? Do you frequently have falls?' Because having a fall when you’re on a blood thinner can be very dangerous.”
Who is at risk for blood clots?
Age as well as certain medical conditions, such as cancer, can increase the risk of blood clots in individuals. Other conditions that may predispose someone to blood clots include autoimmune diseases or inflammatory diseases, as well as being pregnant or taking birth control containing estrogen.
What are common causes of blood clots?
Some factors and conditions that can lead to blood clots include heart arrhythmia, heart attack, heart failure, obesity, pregnancy, and prolonged sitting or bed rest, as well as smoking, stroke, and surgery.
“People who have a family history of clotting may have a much higher rate of blood clots than someone who doesn’t,” says Chaturvedi. “Also, if you’ve already had one blood clot, your risk of having a second one is higher. There are a lot of different kinds of risk factors here.”
