Swelling of the legs is abnormal and should be evaluated by a physician if it occurs more than occasionally after a long day of sitting or standing. Pain or tenderness in the legs associated with swelling is an especially important reason to seek evaluation. While some of the causes of leg swelling may be minor self-limiting conditions, others require very urgent medical care to reduce the likelihood of major complications or death. Untreated leg swelling may lead to other complications such as infection, poorly-healing wounds, or clots in leg veins.
Evaluation of leg swelling begins with a review of symptoms, personal and family medical history, and a clinical exam which may include heart, lungs, abdomen, pelvis, legs, and nerve/muscle function in the legs. Further testing is based upon the clinical assessment and may include ultrasound, X-ray,CT, or MRI imaging in the legs or evaluation of the heart or blood vessels in the abdomen or pelvis. The most common failure of diagnosis occurs due to a venous ultrasound study which is performed in a manner to rule out clots, known as deep vein thrombosis, in the deep veins of the legs and does not evaluate for failure of one-way valves in the leg veins (venous insufficiency). It is common for patients with chronic leg swelling to be told that the ultrasound is “normal” or “was negative for clot” while failing to test for treatable venous insufficiency.
Leg swelling may affect both legs equally or may be more of a problem in one leg. The causes of swelling in one leg may be similar to the other leg, but it is not unusual for different factors to cause the swelling in each leg. Frequently, leg swelling is caused by more than one factor such as venous insufficiency, obesity, and previous saphenous vein harvest for heart bypass surgery.
Swelling may occur due to high pressure in the veins of the legs, local injury, inflammatory changes, obstruction of lymphatic fluid outflow, infection, low blood protein levels, obesity, pregnancy, fluid retention states, or drug effects. High pressure in the veins of the legs results in fluid, proteins, and blood cells leaking through the wall of small veins into the soft tissues, especially near the ankles. This causes pitting edema, swelling which will leave a temporary indentation in the skin with pressure from a shoe, sock, or intentional pressure such as a squeeze with a finger. Some of the causes of leg edema due to elevated venous pressures include:
Venous insufficiency, a failure of one-way valves in the veins,
Obesity, which increases the pressures on veins and lymphatic channels in the abdomen and pelvis resulting in a partial obstruction of venous and lymphatic outflow from the legs back to the heart,
Deep vein thrombosis, clots obstructing venous flow back to the heart,
Post-phlebitic syndrome, chronic obstruction of veins in the leg or pelvis due to previous deep vein thrombosis,
Compression of pelvic veins due to an overlying artery, organ, or tumor,
Failure of the calf muscles to pump venous blood out of the legs due to stroke, venous injury, arthritis limiting ankle motion, or inactivity.
Localized swelling may be due to trauma, hematoma (collection of non-flowing blood in the soft tissue), infections, fracture, superficial thrombophlebitis (clots in veins of the fatty tissues), rupture of a tendon or muscle, cyst at a joint (such as a synovial cyst at the knee), and, sometimes, spontaneous bleeding into the tissue due to a ruptured blood vessel.
Chronic leg swelling may also be due to states that result in generalized body fluid expansion which may be more apparent in the legs due to the effect of gravity such as:
Low protein states such as malnutrition, protein loss due to illness, kidney, or intestinal diseases,
Some of the most common medications which cause leg swelling are non-steroidal anti-inflammatory drugs taken for pain relief or for arthritic discomfort and calcium channel blockers taken for heart disease or hypertension. Some of the more common drugs which may cause swelling in some individuals include:
Calcium channel blockers
Nonsteroidal Anti-inflammatory Drugs
Ibuprofen, naproxen, and many others in this class
Estrogen, progesterone, testosterone.
Cellulitis, infection of the skin and fatty tissues of the leg may cause swelling with pain and tenderness. Pain from cellulitis may be very severe or may manifest as tenderness and mild pain with faintly pink to bright red skin.
Swelling of the foot, especially if the skin does not pit with brief application of pressure, may be due to lymphedema, a failure of the microscopic network of channels which move tissue fluid from the extremity back to the blood stream at the level of the upper chest. Some of the causes of lymphedema include:
Congenital—present at birth,
Acquired– due to recurrent infection or obstruction
Post-surgical—excision of vein for vein grafts, lymph node dissection for tumor,
Malignancy—lymphoma or other diseases affecting the lymph nodes,
Obesity—due to compression of lymphatic channels in the abdomen or pelvis.
After venous insufficiency, obesity is the next most common cause of lower extremity swelling in the United States. Abdominal obesity partially obstructs venous outflow and lymphatic outflow from the legs. Obesity also accelerates the stretching of the leg veins due to the effects of gravity, thus contributing to the progression of venous insufficiency.
Treatment of lower extremity swelling depends upon the cause. Frequently, conservative measures are helpful and these often are started before the cause of the swelling is fully evaluated. Conservative measures may include:
Weight loss, if applicable,
Periodic elevation of the legs higher than the heart,
Avoiding prolonged sitting or standing,
Performing calf muscle pump exercises frequently when sitting or standing,
Routine daily use of graduated compression support hose, often rated at a compression level of 20-30 or 30-40 mm Hg.
Treatments are directed at the underlying cause of the swelling and may include:
Treatment of venous insufficiency by removing or sealing shut the leaking veins with minimally-invasive techniques,
Treatment of venous thrombosis with techniques that dissolve fresh (acute) clot or by anti-coagulation to prevent additional clot formation,
Relieving venous obstruction in the abdomen or pelvis with angioplasty and stenting or vein bypass graft procedures,
Treatment of cellulitis (infection),
Treatment of heart failure; kidney, liver, intestinal, or hormonal disorders,
A trial of medication cessation under physician supervision.
Lymphedema may require special treatments called manual lymphatic drainage to massage the legs over a period of time with wrapping of the legs in special “short-stretch” elastic wraps and, sometimes, compression pump therapy to mobilize lymphatic fluid from the legs back to the bloodstream in the chest by intermittent squeezing of the legs.
Management of swelling of the legs often becomes a lifelong issue, but it is important because swelling will increase the risk of infection or leg ulcer and the underlying conditions may be associated with serious complications such as deep vein thrombosis or difficulty healing injuries or surgical incisions. Resolving lower extremity swelling, if possible, prior to extremity surgery is an important means of reducing the chances of wound healing complications including bleeding, hematoma, wound breakdown, or infection. Chronic swelling of the legs with discomfort or a heavy feeling to the legs often contributes to inactivity which worsens the problem since the calf muscle pumping of blood out of the legs with walking is an important means of getting venous blood back to the heart.