Though the causes of deep vein thrombosis (DVT), a blood clot which blocks circulation and can travel to the heart, are various, treatment these days is comprehensive and can be effected long before the thrombosis gets out of hand.

What are the symptoms?
The symptoms of DVT are classically pain and swelling of the leg, but the symptoms vary according to the individual, the location and depth of the thrombosis, says consultant vascular surgeon Dr Mark Whiteley. “A small DVT in the calf is likely to produce some ankle swelling and often tenderness in the calf muscle, while a larger one in the thigh or pelvis will probably produce swelling of the whole of the lower leg, and an aching pain in the calf or thigh muscles.”

When do you visit a doctor?
“If you know your leg is more aching or tender than usual, particularly after an illness, operation, aircraft flight, long car journey or anything else that might have been slightly different from your normal routine, then you should seek medical advice sooner rather than later,” says Whiteley.
Ideally you should seek a doctor who has access to a high resolution duplex ultrasound scan, as it is often misdiagnosed, and can be confused with Baker’s cyst, found in the back of the knee joint, which often mimics the symptoms of DVT.

Main causes and risk factors·
Hereditary factors. The highest risk groups are really those with genetics predisposing them to deep vein thrombosis; a condition known as thrombophilia. “Such people often have a history of clots in their veins elsewhere or previous DVT. If female, they may have a history of early miscarriage, and often there is a family history of deep vein thrombosis or other clots,” says Whiteley.
· Age; the risk of DVT increases with age;
· Agents that thicken the blood such as smoking, oral contraceptive pill, dehydration (ie: sweating profusely, excess alcohol, excess caffeine), recovery from injury or surge
· Things that change the flow of the blood; sitting or lying still for long periods of time, varicose veins (which allow blood to flow the wrong way due to the valves is failing), tight compression or pressure on one area of the leg;
· Damaged vein walls, such as from previous deep vein thrombosis, trauma to the legs that damages the veins or abnormal veins such as varicose veins;
· Cancer;
· Illness, operation or long-haul air travel.

What are the chances of death?
Deep vein thrombosis does not cause death itself. “Very occasionally, however, if the thrombosis is very large and high in the leg or pelvis, where the veins are bigger, part or all of the thrombosis can break off and travel through the venous system to the heart and into the lungs. When this occurs, it is called a pulmonary embolism, which can cause death,” says Whiteley.
“A deep vein thrombosis in the calf is very small and the chance of a pulmonary embolism is virtually nil, provided treatment is started to prevent the clot from growing. Even a larger DVT behind the knee is unlikely to cause a pulmonary embolism,” says Whiteley, adding that only one in 10 000 to one in 100 000 people from a pulmonary embolism caused by DVT.
“Another problem is that most people with a pulmonary embolism get one without knowing they’ve ever had a deep vein thrombosis. It is vital to seek help if you are diagnosed with a DVT,” concludes Whiteley.

In addition to a reliable blood test, specialist duplex ultrasound scanning done by a vascular specialist is the most accurate and thorough method of diagnosis and treatment.
“Until recently, surgeons removed deep vein thrombosis surgically or broke it down using either chemicals (called thrombolysis) or mechanical means (called catheter-based thrombectomy). However, except in exceptional circumstances, these techniques usually cause more problems than they have advantages,” says Whiteley.
For the most part, the human body is able to break down the thrombosis itself, if it is allowed to. “Therefore the main treatment is to give anticoagulation to stop any more clots forming on the thrombosis and letting it grow, whilst also allowing the body’s white blood cells to eat away the thrombosis that is already there.”
Anticoagulation treatment usually entails heparin injections immediately and warfarin tablets for several months. “Once the DVT is cured, the vein usually goes back to normal function. However, if it has been particularly bad or if there have been several in one area, the valves in the deep vein can be damaged, as can the vein wall. This can lead to leg swelling and ulceration, so a follow-up duplex ultrasound scan after warfarin treatment has finished, is recommended,” advises Whiteley.

(Published in Aquarius, Dubai. Copyright owned by the author.)