1. Swelling in one limb
A swollen leg or arm is one of the most common signs of a DVT. “Blood clots can block the healthy flow of blood in the legs, and blood can pool behind the clot causing swelling,” says Dr Navarro.
It’s normal to overlook leg swelling as a symptom of a DVT if you always get large or stiff legs when you fly or during periods of immobility. But be suspicious if your bloated limb comes on quickly, especially if it shows up with a side of pain.
2. Leg or arm pain
Usually, DVT pain comes as a combo with other symptoms like swelling or redness, but sometimes it can stand alone.
“Unfortunately, pain from a blood clot can easily be mistaken for a muscle cramp or strain, which is why the issue often goes undiagnosed and is specifically dangerous,” says Dr Navarro.
DVT pain tends to strike when you’re walking or when you flex your foot upward. If you have a muscle spasm you can’t seem to shake—especially if the skin near it is warm or discoloured—have your doctor take a look.
3. Redness on your skin
While it’s true that a bruise is a type of blood clot, it’s not the kind you have to worry about. You can’t see a DVT. You might see some bruise-like discoloration, but you’re more likely to see red. A DVT causes redness in the affected limb and makes your arm or leg feel warm to the touch.
4. Chest pain
A pain in your chest may make you think heart attack, but it could be a pulmonary embolism.
“Both a PE and a heart attack share similar symptoms,” says Dr. Navarro. However, PE pain tends to be sharp and stabbing, and feels worst when you take a deep breath.
Heart attack pain often radiates from upper areas of your body like your shoulders, jaw, or neck. The biggest clue is in your breathing—PE pain gets steadily worse with every breath you take. Either way, you need help immediately, so call 000.
5. Shortness of breath
A blood clot in your lung slows your oxygen flow, and that can leave you feeling winded.
“You often won’t have the stamina or breath to make it up stairs. You feel lousy,” says George Teitelbaum, MD, interventional neuroradiologist and director of the Stroke & Aneurysm Center at Providence Saint John’s Health Center in Santa Monica, Calif.
Get help quickly, especially if this comes on suddenly.
6. Unexplained cough
Can’t stop hacking? If you’re also having shortness of breath, fast heart rate, or chest pain, it could be a PE.
“The cough will be dry, but sometimes people can cough up mucus and/or blood,” says Dr Navarro.
When in doubt, phone your doc or go straight to the ER.
7. A racing heart
When oxygen is low, your heart rate goes high to try to make up for the shortage. Feeling a flutter in your chest and having trouble with deep breaths could be your body sending out an SOS that you’ve got a PE lurking in your lungs, Dr Teitelbaum says.
“For a small blood clot, the heart rate rises in part due to chest pain, shortness of breath, and the related anxiety that these cause,” says Lewis Nelson, MD, chair of the department of emergency medicine at Rutgers New Jersey Medical School.
There is also a release of chemicals from lung tissues that leads to a rise in heart rate.
If the clot is larger, it can cause a reduction in blood oxygen content “and even changes in blood flow that lead to a compensatory rise in heart rate,” Dr Nelson says.
8. Feeling faint
“The lightheadedness is due in part to the chemical released from the lungs, changes in oxygenation of the blood, and in the blood pressure and heart rate,” Dr Nelson says. “The brain is sensitive to changes in oxygen and to changes in blood flow.”
While it’s not an overly common symptom of a blood clot, it happens enough. One study published in the New England Journal of Medicine found that pulmonary embolisms were responsible for about 17% of hospitalisations for fainting in the 560 older people who were studied.