Deep Vein Thrombosis
Deep vein thrombosis occurs when a blood clot forms in a deep vein, most commonly in the legs but sometimes in the arms. It can cause pain, swelling, and changes in skin colour, and requires prompt assessment because of the risk of the clot travelling to the lungs. Early recognition and treatment are key to preventing complications and ensuring a safe recovery.
Overview | Symptoms & Causes | Diagnosis | Treatment Options
What is DVT?
Deep vein thrombosis (DVT) happens when a blood clot (known medically as a thrombus) forms in one of the deep veins of the body, most often in the lower leg, thigh, or pelvis. These veins carry blood from the legs or arms back toward the heart.
When a clot forms inside a deep vein, it can partially or completely block normal blood flow. The main risk is that part of the clot can break off and travel through the bloodstream to the lungs - a serious and potentially life-threatening complication known as a pulmonary embolism (PE).
Understanding Deep Vein Thrombosis
Deep vein thrombosis (DVT) can occur in either the legs or the arms, though it is more common in the legs. Some people have no obvious symptoms, but when they do occur, they can include:
- Swelling in one limb - usually the calf, thigh, or arm.
- Pain or tenderness, often described as a cramp, ache, or feeling of heaviness that may worsen when moving or standing.
- Warmth in the affected area.
- Red, blue, or discoloured skin.
- Enlarged or visible veins near the surface.
Seek urgent medical attention if you notice any of these symptoms, particularly if they come on suddenly.
You should call 999 or go to A&E immediately if you experience:
-Sudden shortness of breath
-Chest pain that worsens with breathing
-Coughing up blood
These could be signs that the clot has travelled to the lungs - a pulmonary embolism - which is a medical emergency.
Causes and Risk Factors
A DVT develops when blood flow in a deep vein becomes slow or blocked, allowing a blood clot to form. This can happen for several reasons, often involving a combination of factors. You may be more at risk if you:
| Reduced movement | Long periods of inactivity, such as long flights or bed rest after illness or surgery, slow blood flow and increase the risk of clots. |
| Recent surgery or injury | Operations or injuries, especially to the legs, hips, or abdomen, can damage veins and raise clot risk. |
| Previous clotting events | A history of DVT or pulmonary embolism significantly increases the likelihood of another clot. |
| Medical conditions | Long-term illnesses such as cancer, heart disease, or inherited clotting disorders can increase clot formation. |
| Hormonal factors | Hormone replacement therapy, the combined contraceptive pill, and pregnancy or recent childbirth can all elevate clotting risk. |
| Lifestyle factors | Smoking and excess body weight can impair circulation and raise the risk of DVT. |
| Family history | Having a close relative with a blood clot increases personal risk. |
| Age | Risk increases over 60, although DVT can occur at any age. |
Diagnosing a DVT
If your doctor suspects a DVT, they will assess your symptoms and medical history and may perform one or more of the following tests to confirm the diagnosis:
| Physical Examination | Your doctor will look for swelling, tenderness, redness, or warmth in the affected arm or leg. |
| Blood Test | A D-dimer blood test measures a substance released when a blood clot breaks down. A normal result can help rule out DVT in many cases. |
| Ultrasound | This is the main test used to diagnose DVT. It uses sound waves to create an image of the blood flow in your veins, showing whether a clot is present. |
| Additional Imaging | In some cases, a special dye and X-ray, CT, or MRI scan may be used to locate a clot or check for complications if ultrasound results are unclear. |
Treatment Options
The main goal of treatment for a deep vein thrombosis (DVT) is to stop the clot from getting bigger, prevent it from breaking off and travelling to the lungs (causing a pulmonary embolism), and reduce the risk of future clots.
Treatment depends on your health, the location of the clot, and any underlying risk factors, but usually includes:
| Anticoagulant (blood-thinning) medication | These medicines, such as heparin or warfarin, help prevent new clots from forming and stop existing ones from growing. Most people will need to take these for several months. Newer oral anticoagulants (DOACs) are often used as they don’t require regular blood tests. |
| Compression stockings | These special stockings help improve blood flow in your legs, reduce swelling, and lower the risk of long-term complications such as post-thrombotic syndrome (chronic swelling and discomfort). |
| Keeping active | Once treatment has started, gentle walking and leg movement are usually encouraged to improve circulation, unless your doctor advises otherwise. |
Regular check-ups may be needed to monitor your response to medication and ensure the clot is resolving.
In rare or severe cases, other treatments may be considered, such as:
- Clot-dissolving medication (thrombolysis)
- Surgical removal of the clot (thrombectomy) - usually reserved for large or life-threatening clots.
How can Lanthorn help?
DVT Ultrasound - £300
The first-line test for diagnosing DVT. It shows blood flow in real time and can identify the presence, location, and extent of a clot in the arm or leg.
Follow-up Ultrasound - £300
For patients with known DVT, repeat scans can be arranged to monitor clot resolution or check for ongoing symptoms such as post-thrombotic changes.
Specialist referral and follow-up planning
If a clot is confirmed, you can be referred promptly to the appropriate medical team (e.g., haematology or emergency care) for anticoagulation and follow-up.
