DEEP VENOUS THROMBOSIS

A Deep Venous Thrombosis, (DVT) describes where a blood clot forms in a vein deep inside the body, i.e. not just underneath the skin. Deep Vein Thromboses can occur anywhere in the body, however they are most prevalent in the legs. Other locations include the abdomen, the pelvic area and the arms.

In medical terminology a DVT is an 'acute' blood clot, in other words it is a new, previously undiagnosed, clot as opposed to a 'chronic clot' which describes one that is already diagnosed.

Blood clotting is the body's natural reaction to prevent blood loss in case of injury either on the skin or inside the body (the medical term for the process of blood clotting is 'thrombosis').

When blood clotting occurs within a vein, it not only disrupts blood flow, either by slowing the flow or blocking it altogether, it can be very dangerous if the blood clot dislodges. If it travels through the veins to the lungs it can cause a 'pulmonary embolism' which can be fatal.

Causes

There are a number of factors that are known to increase a person's risk of developing DVT.

Hereditary factors

Genetic mutations which can predispose a person to DVT, especially if both parents carry the mutation/s, such as:

'Factor V Leiden'
'Prothrombin mutation'

Other genetic mutations which result in overproduction or underproduction of some blood components can make people carrying these genes more prone to blood clotting.

Types of injuries

Leg injuries which involve damage to the walls of the veins.

Medical conditions

Some medical conditions can increase the risk for DVT, for example:

Cancers such as Colon (bowel), liver, stomach, lymphatic, ovarian and pancreatic
Bowel conditions (such as Crohn's disease)
Rheumatoid arthritis

Medical treatments

Some Medications can increase the risk of DVT, such as:

Medications – hormone replacement medications and the contraceptive pill
Radiation therapy

Body weight

People who are overweight or obese are more at risk of developing DVT.

Being a smoker

Smoking is considered a moderate risk factor.

Being pregnant

Pregnancy is considered a high-risk factor, especially during the third trimester and immediately after giving birth.

Age

From the age of 60 the risk of developing DVT increases.

Long periods of inactivity

Any extended period of sitting or lying, such as long-distance trips or recovering from medical treatment in a hospital bed, increases the risk of developing DVT. Any extended period of sitting over 5 hours is regarded as an increased risk.

Any one of the risks outlined here increase the overall risk of developing a DVT. However, it is where several of these risk factors occur that there is a substantially increased risk of developing DVT.

Symptoms

The following symptoms may indicate the presence of DVT;

Chronic pain and/or tenderness in the leg

Swelling ('phlebitis') of the lower leg, sometimes extending to the ankle and foot; changes to the skin/warming of the skin in the affected area (these symptoms are referred to as 'post thrombotic syndrome').

Pain that comes on when extending the foot

Leg ulcers

Symptoms of pulmonary embolism include:

Pain in the chest

Heart palpitations

Cough

Shortness of breath

If any of the symptoms of pulmonary embolism appear it is vital to seek urgent medical attention.

Tests / Diagnosis

DVT is diagnosed using a number of diagnostic methods, which may include:

Ultrasound

Venography – this is a type of X-ray where contract dye is injected into the veins

MRI

Treatment

The primary non-surgical treatment for DVT is anticoagulant medication (e.g. Warfarin or Heparin) which stop new clots from forming. In some cases, a 'thrombolytic agent' may be recommended which is a type of medication which breaks down an existing thrombosis.

The main surgical approach is to remove the clot, known as a thrombectomy which can be done in a minimally invasive procedure.