You’re getting dressed for the day and notice something odd — one shoe feels a bit snugger than the other. You take off your shoes and have a good look at your feet. Hmm. That foot does look significantly puffy and swollen. The ankle also looks much too plump, and what is that cramping up the back of your calf?
These could all be signs of a blood clot in your leg. The condition is known as deep vein thrombosis and affects 1 out of every 100 senior adults.
What is deep vein thrombosis
A thrombus is a blood clot that forms inside a vein. Thrombosis is the process of that happening. Deep vein thrombosis is a serious health condition that occurs when a thrombus forms in a deep vein.
Deep vein thrombosis, or DVT, in more depth
The human body has 2 kinds of blood-carrying tubes: arteries, which send oxygenated blood from the heart outwards, and veins that bring oxygen-depleted blood back to heart.
‘Deep’ veins are the largest veins in your body, located deep inside muscles. The largest of these is the common femoral vein that runs from near the stomach down to the knee. At its widest point, the femoral vein has a diameter of 10.5mm. For comparison, the diameter of a standard #2 school pencil is 7mm.
The full length of the deep vein network in your legs ends near the lower shin. Around 90% of all the blood in your legs is contained in these deep veins.
How does a thrombus form
What happens when you get a surface skin cut? You bleed a bit, then the blood starts to coagulate and clump up, then dries into a scab.
In the same way, if a vein gets torn, cut, or damaged in any way, platelets and protein molecules in the blood band together to patch the scratch. This is known as a thrombus, or blood clot.
Dangers of deep vein thrombosis
A thrombus that is too large disrupts the smooth, steady, and speedy flow of blood. If it breaks away from the venous wall, it can float along in the bloodstream, growing bigger and bigger until eventually it gets stuck.
A thrombus stuck in a vein acts like a dam, forcing blood to pool up behind it. Tissue cells deprived of blood begin to die, leading to a condition known as deep vein thrombosis necrosis.
A thrombus that travels up and gets lodged in a lung is called a pulmonary embolism. Since the blockage prevents the lung from supplying oxygen to the heart, it can lead to death.
Risk factors leading to deep vein thrombosis
You may be at higher risk of developing a deep vein thrombus if you:
- Are of more advanced age. The risk of thrombosis grows the older you get.
- Have had surgery, especially in the lower half of your body, such as a full or partial hip replacement, or some kind of abdominal surgery.
- Have some form of heart disease such as atherosclerosis, lung disease, or diabetes.
- Have close family members who also have deep vein thrombosis.
- Travel extensively by air, or are/were an airline pilot (cabin crew is at low risk as their job requires them to stand a lot or walk up and down the plane).
- Work a desk job that involves remaining seated for long periods of time, and do not offset that with adequate exercise.
- Are not mobile and must spend a large amount of time either in bed or in a wheelchair.
How to check for a blood clot in your leg
Sometimes it’s hard to identify signs of a blood clot in legs, especially at an early stage and if the thrombus is not that big to significantly affect blood flow.
Other deep vein thrombosis symptoms are more obvious:
- One leg and/or foot feels and looks swollen compared to the other.
- There’s a cramping or throbbing pain in your thigh or calf.
- Your leg, or a section of the leg, feels noticeably warmer than other areas of the body.
- The skin on your leg has darkened to some shade of red or purple.
How to prevent a blood clot from forming in your leg
You can avoid the need for treatment by taking preventative care measures.
- Move around: Sitting down too often or for too long ages you faster, and ages you badly. Experts state that “even one hour of sustained sitting causes blood to pool in the legs”, and may lead to the development of a blood clot.
- Sit like a queen (even if you’re a king): The ‘Duchess Slant’ came to prominence some years ago when people started wondering why royal ladies sat with their legs crossed at the ankle, rather than at the knee or thigh.
Well, they sit like that for reasons of etiquette, but from a health perspective, crossing legs at the knee or thigh cuts off blood circulation and may cause a blood clot to form. Ideally, though, you should sit with legs uncrossed and both feet on the floor.
- Keep weight under control: Obese individuals are more likely to develop venous stasis, a condition where blood pools in the lower legs and struggles to flow back to the heart for oxygenation. As the pooled blood stagnates and thickens, it may start to clot.
- Drink lots of water: Blood thickens when you are dehydrated, and your heart has to put in a lot more effort to pump. Thicker blood also has trouble flowing easily around a thrombus partially blocking a vein. Water is essential to keep the consistency of your blood thinner and more flowing.
- Wear compression socks: Medical grade compression socks are tight at the ankle and loosen up as they go up the leg. This helps stop blood from pooling in the feet, and adds an extra boost to help push blood up and back toward the heart.
When to speak to a doctor
As with any illness or health condition, you should set an appointment with your doctor as soon as you see any symptoms.
Treatment for deep vein thrombosis can range anywhere from taking blood-thinning medication to needing surgery, but as this health condition is quite preventable, the smart choice is to keep it from happening in the first place.