Different Clots - Superficial Thrombophlebitis and Deep Vein Thrombosis

There are two main systems of veins in the leg.

There are the deep veins which lie deep inside of the muscles. These are the main 'pumping' veins of the leg as they are pumped by the surrounding leg muscles.

The superficial veins lie in the fat between the muscles and skin. Sometimes the ones very close to the skin can be seen as green or blue tubes just beneath the skin. However, in most people, the superficial veins lie surrounded by the fat of the legs and cannot be seen or felt from the surface.

It is for this reason that no doctor or nurse - no matter how clever or experienced - can accurately tell what is going on in the veins without a duplex Ultrasound scan.

• Both the deep and the superficial veins can get clots within them.
• A clot in the superficial veins is called "Superficial Thrombophlebitis".
• A clot in the deep veins is called a "Deep Vein Thrombosis" or DVT.

Superficial thrombophlebitis (often called phlebitis)

If a thrombosis (clot) occurs in the superficial veins just under the skin, there is often a painful lump that can go red. It is usually localised to just one area although it can be long or branched just as the vein is.

Unfortunately, many general practitioners or nurses see a painful red lump on the leg and think this is an infection and often give antibiotics. This is obviously the wrong treatment as there are no bugs to kill - the redness and pain are coming from inflammation of the clot.

The correct treatment would be aspirin or other nonsteroidal anti-inflammatory drugs.

Superficial thrombophlebitis is painful and can leave brown stains on the skin. However it is not usually dangerous and only rarely does the clot propagate and spread into the deep veins.

If there is any doubt at all, a specialised venous Duplex Ultrasound scan can confirm the diagnosis.

If the pain is extreme, it is possible to perform a small operation under local anaesthetic to release the clots from the veins. Releasing the clots this way speeds up the recovery from the thrombophlebitis and reduces the risk of brown staining.

Superficial thrombophlebitis almost always comes from Varicose veins - The vessel wall and the flow are both altered in varicose veins (see virchow's Triad in "Causes of Clots").

The only way to stop the superficial thrombophlebitis from recurring again in the future is usually to remove the varicose veins - nowadays one of the new methods of varicose vein surgery should be used under local anaesthetic (see www.veins.co.uk).

Deep vein thrombosis (DVT)

A deep vein thrombosis is a clot in the deep system of veins in the leg. The severity of the symptoms and the risks really depend on where the clot occurs.

A DVT in the calf (or below knee) is usually tender but poses very little risk. Most doctors will treat this with a short course of heparin and will keep the patient mobile and will scan again in a few days to check the clot has not propagated (got bigger).

An above the knee deep vein thrombosis in the thigh, often causes more pain and swelling in the leg. As such there is more risk that this will damage the deep veins of the leg in a way that may cause more problems in the future. In addition, there is a small chance that this may give rise to a clot that flies off to the lungs - a pulmonary embolism.

A deep vein thrombosis that goes into the pelvis is the riskiest of all. Not only will it cause the whole leg to swell if it blocks off the vein, but if it does not attach firmly to the wall it will fly off as a pulmonary embolism. A pulmonary embolism can make a patient very unwell or even kill them.

Research presented by Professor CV Ruckley has shown that:

• one single DVT that is found and successfully treated rarely causes any long term problems
• multiple DVTs that keep re-occurring can damage the deep veins and the valves in the deep veins, leading to a chronically swollen, painful and discoloured leg that is prone to ulcers - the "post-phlebitic limb".

Therefore it is essential to get an accurate diagnosis as soon as a DVT is suspected or evened questioned - and, if positive, treatment should be started as soon as possible. Treatment should be monitored by blood tests to ensure it is effective - and duplex Ultrasound scans should be used to determine the length of treatment.