In Part one I explained what a DVT is and how it happens. In Part two I looked at the factors that make some people more likely to get a DVT than others. In part 3 I will go through diagnosis and treatment of DVT.
There is a lot written about DVT’s and, for the non-medical person, it all sounds very worrying. So how do you tell if you have one?
The general symptoms like, leg pain, swelling, soreness etc, are very non-specific – everyone gets a bit of pain in the leg from time to time – how do you distinguish between a bit of muscle cramp and a DVT? It can be quite difficult – even for an experienced doctor. Some DVT’s cause very few symptoms, so it really is very tricky to be sure, just by examining a patient.
Fortunately, we have a few tests to help us out.
The first test is a blood test for a chemical called a D-Dimer. This is a protein found in the blood when the body has been breaking down blood clots. If you have a DVT, this chemical level is likely to be raised. If you don’t have one, then it is very likely to be normal.
That’s very helpful, because it allows doctors to exclude DVT’s in a lot of patients by doing a quick and simple blood test.
But what if the D-Dimer level is raised? Even with a raised D-Dimer, it does not mean you definitely have a DVT. The blood test can be raised as a result of many other conditions – for example, after a recent operation, pregnancy, recent injury or a known case of cancer for example.
A raised D- Dimer should prompt a doctor to organise an ultrasound examination of the leg to look directly at the veins for a possible DVT. In skilled hands, this examination should pick up the signs of a DVT if there is one. So if the ultrasound finds a DVT – that needs to be treated.
If the ultrasound is normal, that’s pretty reassuring. It means you are very unlikely to have a DVT. That being said, even the ultrasound is not infallible – so if the symptoms of leg pain don’t get better over a few days, the ultrasound should be repeated, just in case the first examination missed something.
If a DVT is discovered, then you will need to go onto some blood thinning medication, called an anti-coagulant. This is usually given as an initial course of injections of a drug called Heparin (which work very quickly) and then by a course of tablets called warfarin. The tablets take a few days to work and you will need regular blood tests to find out the right dose for you – this varies a bit from patient to patient.
Sometimes doctors use a newer type of anticoagulant which is a fast acting tablet. There are a few of these drugs (Rivaroxaban, dabigatran, apixaban for example), but they all act in similar ways.
Your doctor will prescribe the anti-coagulant for 3 to 6 months in the first instance. Most people can stop the drug after that point, unless it is thought that there is a particularly high risk of the DVT recurring. It is usual for a patient to be seen by a specialist Doctor in Vascular surgery or Heamatology to decide what the risk of a further DVT is and to decide on the duration of treatment needed. A very small number of DVT patients need to take anti-coagulants for the rest of their lives.
You can read more about DVT in our Deep Vein Thrombosis page.