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Volume Overload

By

James L. Lewis III

, MD, Brookwood Baptist Health and Saint Vincent’s Ascension Health, Birmingham

Last full review/revision Jun 2020| Content last modified Jun 2020
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Volume overload generally refers to expansion of the extracellular fluid (ECF) volume. ECF volume expansion typically occurs in heart failure, kidney failure, nephrotic syndrome, and cirrhosis. Renal sodium retention leads to increased total body sodium content. This increase results in varying degrees of volume overload. Serum sodium concentration can be high, low, or normal in volume-overloaded patients (despite the increased total body sodium content). Treatment involves removal of excess fluid with diuretics or mechanical fluid removal via methods such as dialysis and paracentesis.

An increase in total body sodium is the key pathophysiologic event. It increases osmolality, which triggers compensatory mechanisms that cause water retention. When sufficient fluid accumulates in the ECF (usually >2.5 L), edema Edema Edema is swelling of soft tissues due to increased interstitial fluid. The fluid is predominantly water, but protein and cell-rich fluid can accumulate if there is infection or lymphatic obstruction... read more Edema develops.

Among the most common causes of ECF volume overload are the following:

Symptoms and Signs of Volume Overload

Diagnosis of Volume Overload

  • Clinical evaluation

Diagnosis is mainly clinical. Key features include weight gain and edema. The location and amount of edema are dependent on many factors, including whether the patient has been sitting, lying, or standing recently.

Clinical findings vary significantly depending on the cause and are discussed in detail elsewhere in THE MANUAL.

Treatment of Volume Overload

  • Treatment of cause

Treatment aims to correct the cause. Treatment of heart failure, cirrhosis, kidney failure, and nephrotic syndrome are addressed elsewhere in THE MANUAL, but in general treatment includes diuretics and sometimes mechanical fluid removal via methods such as dialysis Overview of Renal Replacement Therapy Renal replacement therapy (RRT) replaces nonendocrine kidney function in patients with renal failure and is occasionally used for some forms of poisoning. Techniques include continuous hemofiltration... read more and paracentesis.

Dietary sodium intake is restricted. Diuretics are given in heart failure, cirrhosis, renal insufficiency, and nephrotic syndrome.

Daily weights are the best way to follow the progress of therapy for ECF volume overload. The speed of correction of ECF volume overload should be limited to 0.25 to 0.5 kg body weight/day, depending on the degree of volume overload (faster with a copious excess, slower with less excess) and the patient's other medical problems (slower with hypotension and renal insufficiency).

Outpatients should be monitored closely when undergoing active diuresis. When there is more severe organ system dysfunction or multiple organ systems are involved or little progress is being made with oral diuretics, inpatient treatment and monitoring are needed.

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