Leg swelling is a very common condition and affects adults of all ages. It is common in pregnancy and is often associated with symptoms such as tiredness and aching and restlessness in the legs.
What are the causes of leg swelling?
Although leg swelling can occur without any particular cause there are many recognised causes which are listed below.
- Chronic swelling in one leg:
- Blockage of the veins or backflow in the veins due to incompetent valves
- A build-up of lymph fluid in the leg (lymphoedema)
- A tumour of the pelvis which can press on the veins and lymphatic channels (rare)
- Reflex sympathetic dystrophy. This is a rare condition that can sometimes follow trauma in the leg
- Sudden onset of swelling in one leg:
- Blood clot in the deep veins of the leg (deep vein thrombosis)
- Rupture of a cyst behind the knee (Baker’s cyst)
- Increased pressure in one or more muscle compartments, called compartment syndrome. This usually follows trauma such as a fracture of the leg.
- Chronic swelling of both legs:
- Blockage of the veins or backflow in the veins due to incompetent valves, affecting both legs
- Heart failure
- Some drugs such as steroids, tablets used to control blood pressure, and the oral contraceptive pill
- A build-up of lymph fluid in the leg (lymphoedema)
- Premenstrual swelling
- Kidney disease (nephrotic syndrome, glomerulonephritis)
- Liver disease
- A tumour of the pelvis
- Continuous sitting/immobility (e.g. elderly patients who sit for prolonged periods and paralysed patients)
- Blood disorders such as anaemia, low proteins in the blood and an inactive thyroid gland
- Following lower limb surgery e.g. joint replacement, broken bones
- Sudden onset of swelling in both legs:
- Blood clot in the deep veins of both legs (deep vein thrombosis)
- Sudden deterioration of heart failure or kidney disease
What are the important things to know about leg swelling?
- The most common cause of leg swelling in patients over 50 years of age is a problem with the leg veins.
- In women under the age of 50 years, the swelling is likely to be “idiopathic” i.e. there is no specific cause that can be identified. Treatment is aimed at reducing the swelling locally in the leg and non-drug therapy is the first-line treatment approach.
- Swelling can be caused by medication and therefore it is important to review any medicines that you are taking and their potential side effects.
- Excessive use of water tablets (diuretics) should be avoided when the swelling results from immobilisation, problems with the veins or problems with the lymphatics.
- In many cases there is more than one cause for the swelling, and treatment of each cause is important.
- Most cases of leg swelling are chronic and whilst they require treatment this is not needed on an urgent basis. Prompt treatment however is required for conditions such as deep vein thrombosis and heart failure.
What investigations do I need?
The precise tests that will be required will depend on your history and presentation. Some of the more common investigations used for leg swelling are listed below:
- Blood tests: a full blood count, electrolyte and kidney function tests, liver function tests, and thyroid function tests. If an acute blood clot in your veins is suspected a test called a D-dimer can be useful to exclude this diagnosis.
- Ultrasound: An ultrasound scan of your lower limb veins will be able to identify if there is any blockage or valve damage in your veins. In some patients an ultrasound scan of your pelvis may also be recommended.
- Tests for lymphoedema. The diagnosis of lymphedema may be made clinically but this can be supported by a test called a lymphoscintigram which measures how rapidly the fluid in your legs drains via the lymphatic channels
- CT/MRI scanning: It is sometimes necessary to get more detailed imaging of your legs and abdomen/pelvis and this can be done using CT or MRI scanning. These tests can also be used to assess if your veins are blocked.
What treatment is available?
Treatment is aimed at the underlying condition but the following are common treatments:
- Reassurance. If the swelling is mild it may not be necessary to start any specific treatment if there is no underlying serious cause.
- Treatment of the veins in the leg. If the veins affected are the ones near the surface of the leg (superficial veins) these may be treated. Common treatments include minimally invasive endovenous ablation (radiofrequency or laser) or sclerotherapy (injection of the veins), and surgery.
- Graduated compression stockings. These are specially designed to exert a higher pressure at the ankle than in the calf or thigh and have been shown to help the drainage of fluid out of the leg in the veins and lymphatic channels. There are particularly useful when there are problems with the deep veins that cannot be treated by other means. They are also used for the treatment of lymphedema, alongside the treatments below.
- Massage. Manual lymphatic drainage is a gentle massage technique that appropriately trained healthcare professionals can perform in order to reduce the swelling in the leg associated with lymphoedema. A modified technique of simple lymphatic drainage can be taught to some patients so that they are able to reduce the swelling themselves.
- Multilayer lymphoedema bandaging. When the swelling of the leg is extensive it is necessary to reduce this before some of the other treatment techniques can be used. Multilayer inelastic bandages are used and these help to drain the fluid from the leg, and are assisted by the action of the muscles in the leg.
- Intermittent pneumatic compression. An inflatable plastic garment is placed on the leg and this is connected to an electrical pump. The garment is inflated and deflated cyclically and different inflation pressures can be applied. This also helps to drain fluid from the leg.
- Diuretics. These are used in the treatment of conditions such as heart failure
- Exercise and elevation. In general exercise is helpful as it builds up the strength of the muscles in the legs and these are important for helping to pump fluid out of the leg. Elevating the leg when resting will help to reduce the swelling due to the help of gravity.
Liposuction. If lymphoedema has been present for a long time it can change from a reversible swelling of the leg due to fluid, to an irreversible swelling due to fat deposition. In such chronic cases liposuction can be helpful in reducing the size of the leg.