edema

Edema is abnormal fluid accumulation in the interstitial space or body cavities due to disruption of fluid balance. It can be localized or generalized and may be pitting or non-pitting. The causes are commonly grouped as increased hydrostatic pressure (eg, congestive heart failure, venous insufficiency), decreased plasma oncotic pressure (eg, nephrotic syndrome, cirrhosis, malnutrition), lymphatic obstruction (lymphedema), and increased capillary permeability (inflammation, infection, certain drugs). Fluid overload from excess sodium and water retention can also contribute.

Clinically, edema presents as swelling of the affected region, often in the legs or ankles, and may be accompanied by weight gain, tight skin, and, with extensive involvement, dyspnea or abdominal distension. Pitting edema leaves a temporary indentation; non-pitting edema occurs with lymphedema or myxedema.

Evaluation includes history and exam, assessment of edema pattern, and targeted tests. Laboratory work may include albumin, liver and kidney function, and thyroid function; natriuretic peptides (BNP) or imaging may be used to assess cardiac causes. Ultrasonography can evaluate venous insufficiency or deep vein thrombosis; imaging for ascites or pleural effusions may be indicated. Lymphatic studies are reserved for suspected primary or secondary lymphedema.

Management focuses on the underlying cause and supportive measures: treating heart failure, liver or kidney disease, or infection; diuretics for volume overload; compression garments and limb elevation for peripheral edema; sodium restriction; and, when appropriate, targeted therapy for lymphedema.