Edema is defined as a palpable swelling produced by expansion of the interstitial fluid volume; when massive and generalized, the excess fluid accumulation is called anasarca. A variety of clinical conditions are associated with the development of edema, including heart failure, cirrhosis, and the nephrotic syndrome, as well as local conditions such as venous and lymphatic disease or malignant ascites (table 1). (See "Pathophysiology and etiology of edema in adults".)
The general principles for the treatment of edema in adults, including the use of diuretics to remove the excess fluid, will be reviewed here. The specific effects of diuretics in the three major generalized edema states (heart failure, cirrhosis, and the nephrotic syndrome), the clinical features and diagnosis of the generalized edematous states, and the treatment of refractory edema are discussed separately. (See "Use of diuretics in patients with heart failure" and "Initial therapy of ascites in patients with cirrhosis", section on 'Diuretic therapy' and "Pathophysiology and treatment of edema in patients with the nephrotic syndrome" and "Clinical manifestations and diagnosis of edema in adults" and "Treatment of refractory edema in adults".)
GENERAL PRINCIPLES OF THERAPY
Treatment of edema consists of reversal of the underlying disorder (if possible), dietary sodium restriction (to minimize fluid retention), and, in most patients, diuretic therapy. Before initiating diuretic therapy, it is important to consider the following questions, which apply to all edematous states:
- When must edema be treated?
- What are the consequences of the removal of edema fluid?
- How rapidly should edema fluid be removed?
When must edema be treated? — Pulmonary edema is the only form of edema that is life-threatening and requires immediate therapy. (See "Treatment of acute decompensated heart failure: General considerations".)