What is Deep Vein Thrombosis (DVT)?
Deep vein thrombosis (DVT) is a blood clot which most often occurs in deep veins in the lower limbs or pelvis. These larger veins pass through the muscles in the thigh and calf in the leg.
Deep vein thrombosis (DVT) affects approximately 0.1 percent of people annually, being more prevalent in elderly people and men.
Recognition and diagnosis of this potentially serious condition are important. Left untreated,the blood clot can travel and block an artery in the lung (pulmonary embolism), which is life threatening. (1)
Symptoms
A blood clot in a deep vein can happen automatically or following a predisposition like surgery, injury or a period of immobility. They usually occur in the calf or thigh but can extend to the pelvic region.
If the all or part of the clot breaks free then it can travel to the lungs blocking an artery there.
There is a very close relationship between deep vein thrombosis (DVT) and pulmonary embolism (PE). As a result there is a medical term, referred to as venous thromboembolism (VTE) which is used to cover both of these conditions. (2)
Only about 50 percent of people with deep vein thrombosis will display symptoms. For the rest, it will occur without warning and the first they know about it, is when a pulmonary embolism (PE) happens. (3)
Due to these close links we will detail the symptoms for both deep vein thrombosis (DVT) and pulmonary embolism (PE).
Deep Vein Thrombosis (DVT) Symptoms
Symptoms of deep vein thrombosis (DVT) include:
Swelling
The affected calf or thigh where the clot is located can swell beyond its normal size. If the clot is in the pelvic region or just above where the veins split to supply each leg then the swelling could be in both legs. (4)
Pain
The limb concerned can feel painful or uncomfortable, which might feel worse when walking or standing. It could also feel like muscle cramps or an ache deep in the leg accompanied by soreness. The leg might also feel “heavy”. (5)
Skin Color
The skin near the vein where the clot is situated might be red or discolored with a purple or blue hue. Particularly in the area at the back of the leg below knee level. (6, 7)
Edema
As well as swelling, water retention can be noticeable and the affected leg will be puffy, plus the skin will also appear stretched. When pressure is applied it will cause an indent that takes a short while to return to normal (pitting edema). (8)
Skin Temperature
The skin where the deep vein thrombosis (DVT) is located feels warmer than usual and hot to the touch. (9)
Surface Veins
The veins closer to the surface of the skin can be affected by the deeper clot. They may appear larger and can feel hard or thickened when touched. (10)
Pulmonary Embolism (PE) Symptoms
As we have previously mentioned, the first indication of DVT might be a pulmonary embolism (PE). Therefore, it is important these symptoms are recognized as well.
The common symptoms of pulmonary embolism (PE) are: shortness of breath, pain when you breathe deeply, breathing rapidly and an increased heart rate.
Less common symptoms include excessive or unexplained coughing which could be accompanied by blood. You might also feel light headed, sweaty and could even faint. Feelings of dread and/or anxiety can also manifest. (11)
Cellulitis
Cellulitis is a bacterial infection of the skin which spreads to deep tissue and muscles. In itself it is a condition that if left untreated can be serious. (12)
It warrants mentioning because the symptoms of cellulitis overlap with the symptoms of deep vein thrombosis (DVT).
Whilst it is rare for people with cellulitis to also have DVT, it is a possibility. (13)
Superficial Thrombophlebitis
This common inflammatory condition is associated with blood clots in the veins close to the surface of the skin. Again, we highlight this because some of the symptoms present similar to deep vein thrombosis. (14)
With this condition there is a probability of also having DVT so you might be screened for deep vein thrombosis if you present with symptoms of superficial thrombophlebitis. (15)
Stages
This condition does not present with stages as such. There are however criteria used to identify the possible presence of deep vein thrombosis.
Called the “wells score”, this assessment is based on risk factors predisposing people to this condition and the symptoms they present with.
The assessment is based on a probability of a person having DVT. It works on a point system allocating one point for each “yes” fitting the criteria. Two or more points indicates that deep vein thrombosis (DVT) is likely while one point or less indicates it is not. (16)
We will detail the criteria and the points allocated to each.
Cancer = One Point
Patient has cancer and is either having ongoing treatment, has had treatment in the last six months or is palliative. (Palliative indicates that a person is receiving specialized care to deal with cancer) (17)
Mobilization = One Point
Patient has paralysis and has either muscle weakness due to neural damage or disease, or has worn a plaster cast recently on either leg.
Bed Rest or Surgery = One Point
Patient has been recently bedridden for three days, or had major surgery in the previous 12 weeks involving local or general anesthetic.
Tenderness = One Point
Patient feels tenderness along the path of the of the deep veins in the affected area.
Leg Swelling = One Point
Swelling is present along the entire affected leg.
Calf Swelling = One Point
The calf of the affected leg is larger by three centimeters or more than that of the unaffected leg. The measurement is taken 10 cm below where the tibia joins the knee.
Pitting Edema = One Point
Swelling due to excess fluid retention is present in only the affected leg. When depressed the skin does not immediately spring back but leaves an indent.
Collateral Superficial Veins = One Point
These large veins are seen on the surface of the leg but are not varicose veins.
Previous DVT = One Point
Patient has previously been diagnosed and treated for deep vein thrombosis (DVT)
Alternative Diagnosis = Minus Two Points
There is another cause for the symptoms that the patient is experiencing equal to or more likely than DVT.
Treatment
The aim of treatments for this condition are to safely disperse the blood clot and lower or eliminate the risk of pulmonary embolism.
Medication
Drugs used to treat this disease are anticoagulants, sometimes referred to as blood thinners. They don’t actually thin the blood, they act by preventing the blood from clotting and dispersing the clot that has built up.
Whilst there are other drugs available, the two most commonly used medications are heparin and warfarin.
Heparin is usually used first because it acts quickly to prevent more clotting. It can be administered via an intravenous drip, an injection into a vein or an injection under the skin.
Warfarin is generally given in tablet form after initial treatment with heparin. It might be prescribed for some months and helps further blood clots forming. Regular blood tests will help your doctor decide the actual dosage and length of time it needs to be taken. (18)
Thrombolytic Therapy
This therapy uses drugs to dissolve blood clots which may be blocking veins or posing a serious or life threatening risks. These “clot busters”, medically referred to as lytics, should be administered as soon as possible to be effective.
An intravenous drip or catheter into the site of the clot are the methods used to deliver this drug. It’s usually performed in an intensive care setting where you can be closely monitored because it can cause excessive bleeding. (19)
Vena Cava
A vena cava is a filter that is placed into the vena cava vein. Made of mesh, it traps fragments that might break from a blood clot and helps prevent blood clots forming.
This device can be fitted under a local anesthetic and is used as an alternative to anticoagulants. (20)
FAQ
What is deep vein thrombosis (DVT)? Deep vein thrombosis (DVT) is a blood clot which most often occurs in deep veins in the lower limbs or pelvis.
What are the signs of deep vein thrombosis (DVT)? The signs of deep vein thrombosis (DVT) are swelling, pain or tenderness, cramps, heat and discolored skin in the affected area.
How do you develop deep vein thrombosis (DVT)? Risk factors involved in the development of DVT are surgery, pregnancy and paralysis. Long periods of immobilization like being bedridden or sitting for long periods like on an aeroplane can also contribute. Genetic factors, age and gender, as well as some medical conditions including spinal injury or cancer, are also predispositions. (21)
How are you diagnosed for deep vein thrombosis (DVT)? Doctors will assess your symptoms and any predisposing factors against a set criteria to help diagnose this condition. They can also use imaging tests and blood tests to check for blood clots.
What is the best treatment for deep vein thrombosis (DVT)? Anticoagulant drugs like heparin and warfarin are usually the first line of treatment for this condition. There are other options like a vena cava filter if these drugs are not suitable or not working.
What are the long term complications of deep vein thrombosis (DVT)? Medications to thin the blood can have adverse effects and prevent your blood from clotting. Taking too many anticoagulants can cause bleeding in the brain or digestive system. (22)
Is deep vein thrombosis (DVT) considered a disability? The prognosis for recovery with DVT when treated is good and it is not considered a disability.
Is there a cure for deep vein thrombosis (DVT)? Yes, there are treatments that can successfully disperse a blood clot from the deep veins.
Is deep vein thrombosis(DVT) life threatening? DVT is a serious condition that if left untreated can lead to pulmonary embolism (PE) which is life threatening.
Summary
Deep vein thrombosis (DVT) is a blood clot that settles in the lower extremities or pelvis. Left untreated, it is a serious condition which leads to pulmonary embolism (PE), a life threatening condition.
Once detected and diagnosed there are treatments available to disperse the blood clot and prevent further clots forming.
Fortunately there are lifestyle changes you can make to help prevent deep vein thrombosis (DVT). These include not smoking, maintaining a healthy weight, eating a healthy diet and exercising. If you are prone to sitting down for prolonged periods, get up and move around or at least move your legs when you can. (23)