Let me explain how to check for a blood clot in your leg.
The presence of any of the 3 S’s might trigger you to suspect a deep vein thrombosis (DVT).
- Signs,
- Symptoms, and
- Situations
Sometimes, there is nothing to see or feel and no clear risks. This happens in as many as 3 in 10 patients.
Disclaimer: See a doctor immediately if you suspect you have a DVT. You will need blood tests and specialized scans to confirm the diagnosis.
How do they form?
Understanding the 3 S’s is easier if you know why deep vein thrombosis (DVT) happens.
- If blood flow slows
- If blood is thick and sticky
- If the vein is damaged
Clots (thrombi) form when blood flow is sluggish and pools; hence, they most commonly form in the legs.
It’s all down to gravity; flow up the leg is more complicated.
It relies on muscle movement to help move the blood up the veins.
For example, when you use your calf muscle, it squeezes the veins inside it. This pushes the blood upwards along the vein towards the heart. One-way vein valves stop the blood from flowing back down when the muscle relaxes.
It makes sense then that you are at risk if you are still for a long time.
- On a long-haul flight, in the middle seat
- Bedridden with illness or after surgery
- Leg in a cast and on crutches
- Sitting for hours eight hours at work
Thick, sticky blood can result from smoking, blood disorders, genetic clotting problems, cancer, obesity, pregnancy, and medication like estrogen.
The clot in the vein blocks blood below it, causing swelling. It irritates the vein, resulting in pain and redness. Usually, only one leg is affected.
The 3 Warning S’s
Remember, not all the signs and symptoms need to be present. As already mentioned, some people have none.
1. Signs – things you might see
- Swelling
- Redness
2. Symptoms – how you might feel
- Pain
3. Situations – things that make your risk higher
- Age > 65 years old
- Overweight (body mass index ≥30 kg/m2)
- Cigarette smokers
- Active cancer
- Estrogen medication(hormone replacement therapy or contraceptives)
- Pregnancy
- Recent surgery (< 4 weeks) with general anesthetic lasting > 30 minutes
- Blood clots history
- Bedwridden or decreased mobility > 3 days
- Genetic clotting tendencies, like Factor V Leiden
- Long-haul flights > 8 hours
Why is it important to know how to check for a blood clot in your leg?
A clot can be life-threatening.
This is called a pulmonary embolism (PE).
A PE may cause
- Chest pain
- Shortness of breath
- A racing heart
- Coughing blood
- Sudden death
The chest pain may be continuous or worse when taking a deep breath.
References
- Yoshimura, N., Hori, Y., Horii, Y., Takano, T., Ishikawa, H., & Aoyama, H. (2012). Where is the most common site of DVT? Evaluation by CT venography. Japanese journal of radiology, 30(5), 393–397. https://doi.org/10.1007/s11604-012-0059-6
- Silverman, D., & Gendreau, M. (2009). Medical issues associated with commercial flights. Lancet (London, England), 373(9680), 2067–2077. https://doi.org/10.1016/S0140-6736(09)60209-9
- Sanford, C., & Lindley, A. (2022a, December 1). Problems in transit – special subjects. MSD Manual Consumer Version. https://www.msdmanuals.com/home/special-subjects/travel-and-health/problems-in-transit
- Stubbs, M. J., Mouyis, M., & Thomas, M. (2018). Deep vein thrombosis. BMJ (Clinical research ed.), 360, k351. https://doi.org/10.1136/bmj.k351
- Wilkerson, W. R., & Sane, D. C. (2002). Aging and thrombosis. Seminars in thrombosis and hemostasis, 28(6), 555–568. https://doi.org/10.1055/s-2002-36700
- Parkin, L., Sweetland, S., Balkwill, A., Green, J., Reeves, G., Beral, V., & Million Women Study Collaborators (2012). Body mass index, surgery, and risk of venous thromboembolism in middle-aged women: a cohort study. Circulation, 125(15), 1897–1904. https://doi.org/10.1161/CIRCULATIONAHA.111.063354
