Edema is swelling in the body caused by excessive fluid accumulating in the tissues. When the amount of fluid in this space is more than 2.5 or three liters, the symptom becomes apparent. When edema is extreme and generalized across the entire body, it is called anasarca. This serious condition often indicates a life-threatening underlying condition.
Edema typically appears as swelling in the feet, hands, and face. In most cases, it is temporary and does not require treatment. Regular edema can be caused by water retention, sitting or standing for too long, and menstruation. When this is the cause, edema generally goes away by itself. Anasarca is much more severe. Rather than being isolated to a limb or body part, it involves tissues all across the body and requires medical treatment.
Early signs of edema include limbs looking swollen, clothing being too tight, being unable to remove a ring from your finger, or heaviness in the limb. Anasarca occurs when this swelling spreads to multiple areas of the body. It may become hard to move affected joints, and the skin may begin to feel warm and taut.
Edema occurs when fluid moves from the vascular space into the tissues. This reduces blood volume, which in turn reduces the amount of fluid reaching tissues. When this happens to the kidneys, they start to retain water and sodium. The body uses some of this extra fluid to replace the lost blood volume, but this fluid primarily enters the tissue if the underlying cause of edema has not resolved. The edema worsens and may progress to anasarca.
Anasarca or severe generalized edema is most often seen in people with heart failure, renal disease, or cirrhosis. Heart failure causes dependent edema in the lower extremities as the veins cannot return blood to the heart efficiently. This type of edema improves when elevating the legs. Anasarca caused by liver failure or renal disease does not change in character when the person stands of elevates their feet.
Anasarca can also result from blood clots, burns, sepsis, trauma, allergic reactions, tumors, lymphatic obstruction, lymph node resections, and malnutrition. Treating edema early, before it progresses to anasarca, can prevent complications that hinder recovery, including skin breakdown, infections, and ulcerations.
Doctors often perform blood and urine tests on people with anasarca to help determine the underlying cause. These include a complete metabolic panel, which may indicate liver and renal function by measuring electrolyte levels in the blood, and urinalysis or 24-hour urine collection to measure albumin and proteins in the urine.
Other diagnostic tools used to treat anasarca include ultrasound to assess the kidneys, confirm venous insufficiency, and evaluate for suspected clots or deep vein thrombosis in the calves. Magnetic resonance angiography evaluates for clots in the thigh or pelvis. MRI is useful in evaluating musculoskeletal problems, and lymphangiography looks at lymphatic drainage if the physician suspects lymphedema.
People who develop anasarca require rapid treatment, particularly if they have heart failure. Doctors can remove two to three liters of fluid in 24 hours without significantly affecting blood volume. Diuretic therapy is the treatment of choice but can lead to volume depletion or low potassium levels. These medications cause increased urine production to encourage fluid loss.
Other interventions for anasarca are mechanical and include leg elevation and compression stockings, though patients with peripheral artery disease should avoid these methods. Preventative measures, including lotions and topical steroids, help maintain the integrity of the skin. Proper skin care is essential to avoid complications like cellulitis and dermatitis.
The prognosis of anasarca heavily depends on the underlying cause. Some causes are reversible but, most of the time, anasarca is a late sign that a problem is past the point of being cured. Most people require hospital admission for diagnosis and treatment. Recovery, when possible, is a slow process.
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