Leg swelling and pain: venous insufficiency and deep vein thrombosis

Swelling does not always mean the same thing

The UK’s National Health Service (NHS) describes swelling of the ankles, feet and legs as usually fluid collecting in the tissue. The most common causes are long periods of standing or sitting, too much salt, being overweight, pregnancy, some medicines (including some blood pressure medicines, contraceptive pills, hormone treatments, antidepressants and steroids), varicose veins and thyroid problems. Sometimes an injury, an insect bite, an infection, a kidney, liver or heart problem, or a clot is behind it.

From this list, two pictures matter most to us. One is gradual swelling of both legs towards the end of the day, which often relates to the veins. The other is sudden, painful swelling of one leg, which brings a clot to mind and does not wait.

Venous insufficiency: swelling that eases when you raise the leg

When the valves in the leg veins weaken, blood pools low in the leg. The NHS says varicose veins may cause ankle swelling, and that symptoms get worse after standing for a long time and better when the leg is raised. The SVS guidance, when it describes chronic vein disease, treats swelling, skin changes and venous ulcers as its more advanced stages.

Take skin changes seriously: itching, darkening of the skin of the lower leg, dryness and flaking. A venous ulcer, according to the NHS, is usually on the inner side of the lower leg between the knee and ankle and lasts more than two weeks. It needs specialist treatment. Compression (bandages or stockings) is the main part of treatment, and the NHS says most of these ulcers heal within six months with the right care.

Deep vein thrombosis

A clot that forms in a deep vein of the leg is called a deep vein thrombosis (DVT). The NHS lists the symptoms as:

• Throbbing pain in the calf or thigh, usually in one leg
• Swelling of one leg (both legs only rarely)
• Redness, bruising or darkening of the skin around the pain (harder to see on brown or black skin)
• Veins that stand out

If the clot is in the arm, the same symptoms appear there. Rarely, the only sign is pain in the lower abdomen.

What raises the risk of a clot: age over 60, obesity, smoking, a previous clot, varicose veins, cancer, heart failure, some inflammatory conditions, and pills and hormones that contain oestrogen. There are temporary factors too: a hospital stay or surgery, three or more days of bed rest, a journey of more than four hours, pregnancy and the six weeks after giving birth, and dehydration. Sometimes no cause is found.

If a clot is suspected

• The NHS treats a suspected clot as urgent. See a doctor or go to a healthcare facility the same day.
• If leg swelling and pain come with shortness of breath or chest pain, the clot may have travelled to the lung. Call 115 (the emergency number in Iran). If you are outside Iran, call your local emergency number. The NHS stresses that you should not drive yourself and should take your medicines with you.
• Other signs of a clot in the lung, according to the NHS: sudden shortness of breath, chest pain that gets worse with a deep breath, coughing up blood, a very fast heartbeat and fainting.

A Doppler ultrasound is needed to confirm it. The NHS says that if a doctor suspects a DVT, the patient should be referred to hospital within 24 hours for an ultrasound.

A superficial clot

Sometimes a clot forms in a surface vein, often a varicose vein. The vein becomes hard, warm and tender. The NHS calls this phlebitis and says treatment may not be needed if it is mild. But the same symptoms may come from a deep clot, so have a hard, painful vein seen the same day.

Swelling of both legs and the heart

Swelling of both legs does not always come from the veins. For heart failure the NHS names: shortness of breath during everyday tasks or when lying down, swollen legs, ankles or abdomen, sudden weight gain, and a night-time cough or a cough with pink, frothy phlegm. If leg swelling comes with these, do not look at the legs alone, and see a doctor the same day. Severe shortness of breath or pink, frothy phlegm means 115.

Assessment

A doctor starts with your history: when the swelling began, whether it is on one side or both, whether it is worse after standing or after lying down, and which medicines you take. Then the legs and heart are examined. Depending on the result, a Doppler ultrasound of the leg, heart checks (such as an ECG) or blood tests may be needed. What is needed depends on your own examination.

Treatment

• Venous insufficiency. Daily care and compression stockings and, for some patients, a procedure on the vein. The common methods are described on the varicose veins page.
• Deep vein thrombosis. The NHS names blood-thinning medicines as the usual treatment and says they normally continue for at least three months. The doctor decides the type and duration of the medicine. Do not stop it on your own. If you are due to have surgery or dental work, tell the doctor beforehand.
• Swelling from the heart or kidneys. The underlying cause is treated, as decided by the doctor.
• Swelling from a medicine. If you think a medicine is the cause, tell your doctor. Do not stop it yourself.

Everyday help

For swelling the NHS says: raise the leg on a pillow or chair, walk gently, wear loose, low-heeled shoes, wash and moisturise the feet, avoid standing or sitting for long periods, and avoid tight clothes, socks or shoes. After a clot, regular walking and raising the legs while sitting are recommended.

When is it urgent?

• Sudden swelling of one leg that is painful, red or warm: urgent assessment the same day.
• Leg swelling with shortness of breath, chest pain, coughing up blood, fainting or a noticeable racing heart: 115 (the emergency number in Iran). If you are outside Iran, call your local emergency number.
• Swelling of one leg after surgery, a hospital stay or a long journey: the same day.
• Swollen legs in a person with diabetes: the same day.

See the full list of signs under “When should I call urgently?”.