CA blood clot is the body’s way of stopping bleeding and is ultimately a life-saving process. However, when a blood clot forms at the wrong place and at the wrong time, it can be dangerous and even deadly. Blood clots within an intact blood vessel reduces blood flow and can sometimes completely block an artery or vein. Deep vein thrombosis (DVT) is one such instance where a blood clot forms within a vein and eventually lead to life threatening complications.
DVT (deep venous thrombosis) is when blood clots form in the deep veins of the leg. This clots arise for several reasons but is usually associated with prolonged rest. The blood in the lower leg and foot does not return to the heart as easily as in other parts of the body. Physical activity is an important factor in pushing the blood out of the legs. When a person is inactive for long periods then the pooling of the blood can lead to clot formation.
Read more on deep vein thrombosis.
How can DVT be deadly?
Despite the symptoms and complications that can arise within the leg, the greater risk in DVT is when the blood clot dislodges. It can then travel via the veins to the heart. Usually the clot is too small to cause any significant problem in the heart. The clot then passes through the heart and into the pulmonary arteries where it causes a blockage. This prevents blood flowing through to become oxygenated. It may also lead to death of a portion of the lung.
This condition is known as pulmonary embolism. It can result in death unless there is immediate medical attention available. However, DVT can also lead to non-fatal consequences. Firstly DVT can be recurrent even after the initial event is treated. Secondly another complication that may arise is known as postthrombotic syndrome (PTS). Recurrence and PTS can occur eben with treatment of DVT.
Signs of Deep Vein Thrombosis
It is important to note that there may be little to no symptoms in many cases of deep vein thrombosis (DVT). It is not uncommon for a pulmonary embolism to occur in a person who had no indication of a blood clot being present in the deep vein of the legs. Therefore DVT should not be diagnosed solely on the signs and symptoms. Diagnostic investigations like a venogram are usually necessary.
Leg Pain and Calf Tenderness
Leg pain is often thought of as a characteristic symptom of deep vein thombosis. However, this is not true. In fact leg pain only occurs in about 50% of DVT cases. The pain may be felt anywhere in the leg, specifically the lower leg, and not only around the area of the blood clot.
Tenderness on the other hand is more common than leg pain. This is where there is pain upon the application of pressure. Most of the time this tenderness is felt in the calf but usually the tenderness is mostly felt at and around the site of the blood clot.
Swelling of the Leg
Another characteristic symptom of deep vein thrombosis (DVT) is leg swelling (edema). It usually occurs on the affected leg and is often one-sided (unilateral). However, it can sometimes occur in both legs (bilateral) if the blood clot is located higher up the arteries supplying blood to the leg.
Swelling of the leg in DVT is not always present in every case. When it does occur it can vary in severity and the severity is not an indication of the size of the clot. This swelling is a result of blood not being able to return to the torso and fluid seeping out of the vein and into tissue spaces.
Temperature and Color of the Leg
Another common sign of deep vein thrombosis is warmth usually over the site of the clot. Unlike with some of the other vascular diseases, the leg may not be cold to touch. Instead the affected area may be warmer than the normal warmth of the leg. There may also be redness of the skin in the area.
The color of the leg may vary. Most of the time it is a red to purple hue since the leg is engorged with venous blood. It appears as tiny red-purple spots (petechiae). Sometimes the leg may turn a blue color (cyanosis) but this is rare. This may occur when the blood clot is high up the veins.
Read more on how to avoid leg clots.
Not every case of deep vein thrombosis (DVT) culminates in pulmonary embolism. Even with treatment, there is still the risk of DVT recurring. In fact as many as 15% of treated cases of DVT recur within a year and without treatment there is a 50% chance of recurrence within 3 months. Apart from the risk of pulmonary embolism, DVT can also lead to another complication known as postphlebitic or postthrombotic syndrome (PTS).
This is a chronic complication of deep vein thrombosis. It may arise months or even years after DVT. Postphlebitic or postthrombotic syndrome is a result of the damage to the vein due to the blood clot (DVT). The valves of the leg vein become incompetent and it cannot help to return blood to the torso. The symptoms of PTS can vary in intensity but is usually triggered and worsened with standing while easing with elevating the leg.
These signs and symptoms of postthrombotic syndrome include:
- Persistent patchy redness of the legs
- Ongoing swelling of the leg(s)
- Chronic pain in the leg(s)
- Ulcers (open sores) on the skin
- Discoloration of the skin on the legs
Cramping, itching and tingling of the legs are some of the other common symptoms of PTS. There is up to a 50% chance of PTS occurring within 2 years of DVT and it can be as high as a 90% chance of PTS arising after 10 years. Compression stockings are usually needed to manage PTS while individual symptoms, like leg ulcers, may need specific treatment. Along with elevating the leg it is only effective in relieving symptoms and preventing ulcer formation.