Blood Clot Symptoms: What To Watch For

Heart attack, stroke, and pulmonary embolism—all three happen in different body parts, yet they can all be caused by a blood clot. Knowing the symptoms of when a blood clot is causing a problem is critical in recognizing when you might be having a medical emergency.

Approximately one person dies every six minutes as a result of a blood clot. Not all blood clots are created equal, though. Blood clots “can range from mildly symptomatic and recoverable to fatal,” Elad I. Levy, MD, professor and chair of neurosurgery at the University at Buffalo, told Health.

While your overall risk of having a blood clot is fairly low, they can and do happen. Here’s what you need to know about blood clots and their symptoms.

Your blood is typically in a liquid state, but a blood clot is a gel-like clump of blood that forms in a process called coagulation. A clot naturally forms in certain situations, like when you have an injury or a cut, to help plug the injured blood vessel and stop the bleeding.

Blood clots can form inside your body without a good reason and block blood vessels. A blood clot can break free and move from one part of the body. They can travel to critical areas of your body, like your lungs, brain, or heart, causing serious and sometimes fatal complications.

They’re so dangerous because they can impede or block blood flow to vital organs in the body, Amita Avadhani, Ph.D., specialty director and associate professor, Division of Advanced Nursing Practice, School of Nursing at Rutgers, The State University of New Jersey, told Health.

“Our vital organs, such as brain, lungs, and heart, need oxygen to function. Without oxygen, the brain cells start dying after four minutes, causing permanent damage to the organs and their functionality as the time progresses,” added Avadhani.

For blood to reach all parts of your body—from the top of your head to the tip of your toes—you have a circulatory system that is made up of blood vessels called veins and arteries. Arteries carry oxygen-rich blood from the heart to other parts of the body. Veins carry oxygen-poor blood back to the heart to get reoxygenated.

Blood clots can also be categorized by their movement—whether or not they’re mobile. A clot that forms in an artery or vein is called a thrombus. A clot that breaks off and travels to another part of the body is called an embolus.

Because two types of vessels carry blood throughout your body, there are also two types of blood clots: arterial clots, which occur in the arteries, and venous clots, which form in the veins.

Arterial Clot

A clot is called an arterial embolism when it forms in an artery and goes elsewhere—usually to the head, heart, legs, and feet—and interrupts blood flow to other parts of the body. Symptoms come on quickly or slowly, depending on the clot size and how much it blocks blood flow, or you may not have any symptoms at all.

Symptoms of an arterial clot or embolism in the legs or arms include:

• A cold arm or leg
• Decreased or no pulse in an arm or leg
• Lack of movement in the arm or leg
• Numbness and tingle in the arm or leg
• Pain in the affected area
• Pale color of the arm or leg
• Weakness of an arm or leg

If arterial blood flow is blocked longer, other symptoms can emerge:

• Blisters on the skin near the affected artery
• Skin shedding
• Skin erosion (ulcers)
• Tissue death, or necrosis.

If an arterial clot occurs in an organ, the symptoms depend on the affected organ. An arterial clot in the brain can lead to a stroke, and one that forms in the heart can lead to a heart attack. Arterial clots can also show up in the kidneys, intestines, and even eyes—though these are rare. In general, symptoms of arterial clots in an organ are:

• Pain in that part of the body
• Temporarily decreased organ function

Venous Clot

A venous clot forms in a vein and can build up over time. The most serious form of a venous clot is deep vein thrombosis (DVT), a condition that happens when a blood clot forms in a deep vein—as opposed to more superficial veins closer to the body’s surface. Those clots usually develop in the lower leg, thigh, or pelvis but can also occur in the arm.

The most serious complication of DVT happens when a part of the clot breaks off and travels through the bloodstream to the lungs. There, it can cause a blockage called a pulmonary embolism (PE), stop blood from flowing to the lungs, and lead to death. DVTs, however, do not lead to heart attacks or strokes.

Symptoms of DVT can include:

• Pain
• Redness of the skin
• Swelling
• Tenderness

Symptoms of PE can include:

• Chest pain or discomfort, which usually worsens with a deep breath or coughing
• Coughing up blood
• Difficulty breathing
• Faster-than-normal or irregular heartbeat
• Very low blood pressure, lightheadedness, or fainting

Cerebral venous sinus thrombosis (CVST) is a venous clot that forms in the brain’s venous sinuses. This type of clot was responsible for a temporary pause on the Johnson & Johnson COVID-19 vaccine after six people developed one. It keeps blood from draining out of the brain, which can cause blood to leak into the brain’s tissues.

Symptoms of a CVST can include:

• Blurred vision
• Coma
• Fainting or loss of consciousness
• Headache
• Loss of control over movement in part of the body
• Seizures

Everyone is at risk of developing blood clots. They can happen to all races and genders of any age. Certain factors increase your risk:

• Being immobile
• Cancer and cancer treatments
• Family history
• Hormone therapy containing estrogen
• Hospitalization
• Injury or trauma
• Long-term diseases, such as diabetes
• Older age
• Overweight or obesity
• Pregnancy and post-partum time
• Smoking or vaping
• Surgery

Knowing your risk and the symptoms are the best way to protect yourself, so you can get help as soon as you can when you suspect you may have a blood clot. Blood clots are preventable and treatable. Tell a healthcare provider if you are at risk of developing blood clots.

Some simple ways of preventing blood clots include:

• Stay hydrated
• Don’t smoke or vape
• Get up and move your legs often if you’re seated for long periods of time
• Wear compression socks if you are at risk for blood clots

If you have any symptoms of a blood clot, seek medical attention ASAP. “You need to be seen,” Anita Gorwara, MD, a family medicine physician and medical director of urgent care at Providence Saint John’s Health Center in Santa Monica, CA, told Health. “Don’t waste time calling your doctor and waiting for them to get back to you. Instead, go to an urgent care center, your primary care physician’s office, or the emergency room right away.”

Timing matters with blood clots. “Cells start dying after four minutes of lack of circulation,” said Avadhani. “This is why when someone has a stroke, the chance of damage to the brain can be minimized or eliminated if the clot is identified and treated promptly.”

It’s important not to brush off your symptoms, stressed Dr. Levy. “If you’re unsure, don’t assume it’s nothing,” said Dr. Levy. “Go get checked out.”

Blood clots are a natural way for your body to stop bleeding from a cut or a wound, but when they happen when they’re not supposed to or break off and end up in a vital area of the body, they can be fatal. Blood clot problems can happen to anyone, although certain factors increase your risk.

Understand the symptoms of what a blood clot can cause so you know to seek immediate medical attention if needed.