Hypervolemia (Fluid Overload)

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What is hypervolemia (fluid overload)?

Hypervolemia is a fluid imbalance. In general, the hypervolemia definition is having too much fluid in the body. Other names for it include fluid overload and volume overload.

Everyone has a certain amount of fluid—or water—in the body. Most of it is intracellular fluid (ICF), which is inside cells. A portion of it is extracellular fluid (ECF), which is outside cells. ECF is fluid in the blood and lymph, between the cells, surrounding the brain and spinal cord, inside muscles and tissues, and everywhere else there is space outside of cells. In hypervolemia, there is too much ECF filling up body cavities and all the spaces between cells. This results in symptoms such as swelling, rapid weight gain, high blood pressure, and shortness of breath.

Fluid overload happens when the body can’t get rid of excess water or holds on to too much water. The issue underneath this is having too much sodium in the body. Sodium triggers the body to retain water in order to dilute it.

Retaining water can be a normal thing when it’s mild. Many people experience minor swelling from eating salty foods. Women may also have problems with water retention during their menstrual cycle. When you’re healthy, the body handles this by rebalancing sodium and water. It excretes the excess sodium and water follows it. However, certain medical conditions can hinder this process. These include kidney disease, congestive heart failure, and liver disease. Having these conditions puts you at risk of developing fluid overload.

Hypervolemia treatment tries to correct the underlying disease process when possible. Strategies to reduce sodium intake and boost fluid output are generally part of treatment. This includes using diuretics to increase urination and dialysis when the kidneys aren’t able to handle the job.

Left untreated, fluid overload can cause serious complications, including worsening heart, kidney and lung function. Contact your doctor right away if you have an underlying medical condition that can cause fluid overload and experience symptoms consistent with hypervolemia.

What are the symptoms of hypervolemia (fluid overload)?

Hypervolemia symptoms are the result of too much fluid in the body. This puts stress on organs and tissues as the fluid expands around them and in them in the spaces between the cells.

Common symptoms of hypervolemia (fluid overload)

Hypervolemia causes the following common symptoms:

  • Edema, which is swelling in the feet, legs, hands, arms or face
  • Rapid weight gain

Fluid overload is a serious condition that can lead to complications. Seek medical care promptly if you experience symptoms and are at risk of developing fluid overload. If you have symptoms and have never been diagnosed with one of the underlying conditions, testing will be necessary to understand the cause of fluid overload.

What causes hypervolemia (fluid overload)?

Fluid overload happens when the body can’t balance sodium and water levels. Too much sodium leads to water retention to try to dilute it. If the body can’t eliminate it, fluid overload occurs. The kidneys have the main job of reabsorbing or excreting sodium and fluid, depending on the body’s needs. Certain medical conditions make it difficult for the kidneys to keep the balance between sodium and water including:

  • Congestive heart failure (CHF), which is the leading cause of fluid overload in the United States. In CHF, the heart can’t pump blood effectively to the kidneys. Without enough blood to filter, the kidneys can’t do their job as well as they should.
  • Kidney failure, which is advanced kidney disease. The kidneys are usually able to keep doing their job with sodium and water until the end stages of kidney disease. Fluid overload is usually rare in earlier stages of kidney disease.
  • Liver cirrhosis, which is permanent liver damage that can lead to liver failure. The liver acts as a filter for blood to remove toxins. With cirrhosis, it can’t filter blood properly. This sends a signal to the kidneys that make them think they need to increase blood pressure to get more blood to the liver. The kidneys start holding on to sodium and water in an attempt to do this. Fluid can also leak out of blood vessels in the liver into the abdomen, causing ascites.

Mild fluid overload can also occur after surgery, during PMS (premenstrual syndrome), and during pregnancy.

What are the risk factors for hypervolemia (fluid overload)?

Hypervolemia is a condition that develops secondarily to another medical condition. Having one of these underlying conditions puts you at risk of fluid overload. Taking in too much salt and water can increase the risk even more.

Reducing your risk of hypervolemia (fluid overload)

If you are at risk of developing fluid overload, your doctor may recommend a low-salt diet. In some cases, you may also need to limit the amount of fluid you drink in a day. However, this can be a fine balance. Talk with your doctor to understand the best way to avoid fluid overload in your circumstances.

How is hypervolemia (fluid overload) treated?

If possible, doctors will treat the underlying problem that is causing fluid overload. This generally includes using diuretics to increase fluid loss through urination. If the kidneys aren’t functioning enough to do this, dialysis can remove excess fluid mechanically. Limiting sodium intake will make it easier to get rid of excess fluid.

What are the potential complications of hypervolemia (fluid overload)?

The complications of fluid overload affect every organ system in the body and can be quite serious. Potential complications include:

  • Cerebral edema, which is fluid on the brain. This increases pressure on the brain and can lead to loss of cognitive abilities, confusion, delirium, seizures and coma.
  • GI edema, which is fluid in the gut wall. This can prevent the digestive system from absorbing nutrients and lead to paralysis of the muscles that keep the digestive tract moving.
  • Myocardial edema, which is fluid on the heart. This makes it difficult for the heart to contract and pump blood.
  • Pulmonary edema, which is fluid in the lungs. This makes it harder for the lungs to exchange oxygen and carbon dioxide.
  • Skin and musculoskeletal edema, which is swelling of the skin and muscle tissues. This can lead to poor wound healing and pressure sores.

Fluid overload can also cause more damage to the organs involved in the underlying condition, including the heart, kidneys and liver.

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Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2020 Dec 1
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