Deep Vein Thrombosis Information

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A deep vein thrombosis (DVT) is a blood clot (thrombus) that develops in a

deep vein, usually in the leg. This can happen if the vein is damaged or if

the flow of blood slows down or stops. Deep vein thrombosis can cause pain

in the leg, and can lead to complications if it breaks off and travels in

the bloodstream to the lungs.

The are two types of veins in the legs: deep and superficial. The deep veins

pass through the centre of the leg, surrounded by the muscles. It's here

that DVTs most often develop. Less commonly DVTs occur in the deep veins of

the arm or pelvis.

Certain factors make a DVT more likely to occur. They are more common in

people aged over 40 and in people who are obese, or who have already had a

DVT. Several inherited conditions make the blood more likely to clot than

usual, increasing the risk. Other factors include:

* prolonged bed rest, (immobility)

* major injuries

* surgery, especially if it lasts more than 30 minutes, or involves the

leg joints or pelvis

* long-distance travel, because of prolonged immobility.

* taking a contraceptive pill that contains estrogen. Most modern pills

contain a low dose, which increases the risk by an amount that is acceptable

for most women hormone replacement therapy (HRT). For many women, the

benefits outweigh the increase in risk.

* other circulation or heart problems

A DVT below the knee is unlikely to cause complications and may only need to

be monitored. But when a clot forms in or above the knee, there is a risk

that it will break away and travel up the vein to block a blood vessel in

the lung. This is called a pulmonary embolism. Depending on the size of the

clot, it can be a life-threatening condition.

A DVT can damage the valves in the vein, so that instead of flowing upwards,

the blood pools in the lower leg. This is called post-thrombotic syndrome,

and can result in pain, swelling, discolouration and sores on the leg.

Symptoms of a DVT may include:

* swelling of the leg

* warmth and redness of the leg

* pain that is noticeable, or worse when standing or walking

Diagnosing a DVT includes:

* bloodwork to assess the clotting properties of the blood

* an ultrasound scan

* venography - using X-rays to show the flow of blood when special dye is

injected into the veins.

Treatments include:

Medicines

The most common treatment is anticoagulant (blood thinning) medicines, which

reduce the blood's tendency to clot. These are usually taken for three to

six months. Regular blood tests are needed to check the levels of the drug

in the blood.

Anticoagulants can stop new blood clots from forming and old ones from

growing. They can't dissolve existing clots. The body does this itself over

time.

The anticoagulants used are heparin or warfarin usually. Anyone taking

these medicines should avoid activities that could increase the risk of

injury. This is because one of the main ways a wound heals is through

clotting, and anticoagulants interfere with this process.

Less commonly, clot dissolving drugs called thrombolytics are used to

dissolve a DVT. They carry a high risk of bleeding, so are only used in

severe cases, where a life or limb is threatened.

Compression stockings

To relieve pain and swelling, and to prevent post-thrombotic syndrome, some

doctors recommend wearing graduated compression stockings, which are tighter

at the foot than higher up the leg. These may need to be worn for several

months or more.

Most people with a DVT are advised to place a cushion under their feet while

resting or sleeping, so that the feet are raised higher than the hips. This

helps to reduce the pressure in the veins of the calves.

Anyone who feels they are at high risk of developing a DVT should seek

medical advice. There are measures anybody can take to help prevent a DVT:

* exercise the legs regularly - take a brisk 30-minute walk every day

* maintain a weight that's appropriate for your height

* avoid sitting or lying in bed for long periods of time without moving

the legs

* women, particularly those over the age of 35, should consider the risks

and benefits of taking the contraceptive pill

Preventive measures for travellers - please consider if you are travelling

this summer anywhere!

Although the added risk of developing a DVT caused by travelling appears to

be low, it can be reduced even further by exercising the legs at least once

every hour during long-distance travel. This means taking regular breaks if

driving, or walking up and down the aisle of a coach, train or plane.

The muscles of the lower legs (which act as a pump for the blood in the

veins) can be exercised while sitting by pulling the toes towards the knees

then relaxing, or by pressing the balls of the feet down while raising the

heel.

Other preventive measures:

* reconsider the use of sleeping pills. These cause immobility,

increasing the risk of DVT

* wear loose-fitting clothing

* keep the legs uncrossed

* keep hydrated by drinking normally (urine should be no darker than a

pale yellow). Avoid alcohol to prevent dehydration

* wear graduated compression stockings. This is particularly important

for travellers who have other risk factors for DVT

* Some doctors recommend taking aspirin before travelling because of its

blood thinning effects. But it is not suitable for children and can have

side-effects. If in doubt, seek advice from a pharmacist or doctor.