Edema in Patients with Eating Disorders and Severe Malnutrition

By Kristin Anderson, MD

Edema in Eating Disorder Recovery

Edema occurs when excess fluid accumulates in the body, causing tissues to swell. This phenomenon tends to affect individuals more often during the refeeding process of eating disorder treatment, although it can happen at other times. In extreme cases, edema can be highly distressing as it can cause rapid weight gain and a great deal of physical and mental discomfort.

Edema formation occurs as a response to many physiologic changes that take place during the refeeding process, as discussed below. Reassurance and therapeutic support are vital when caring for patients with eating disorders who are experiencing edema. Medical professionals can take steps to both prevent and manage edema, putting each patient on a safe path to a long-term recovery.

Forms of Edema

Edema can occur for a number of reasons and under different circumstances, including due to refeeding, Pseudo-Bartter Syndrome, co-occuring with refeeding syndrome and due to low albumin levels.

Refeeding Edema

Individuals with malnutrition undergoing refeeding are at risk for refeeding edema, which occurs during the refeeding process of eating disorder treatment. Fluid retention primarily occurs in the lower extremities, due to this being the most gravity-dependent part of the body. Please note that any edema that occurs during refeeding is not necessarily related to refeeding syndrome. Rather, all patients who are receiving nutritional rehabilitation are at risk for refeeding edema:

  • Carbohydrate intake increases as an individual starts to refeed, leading to a release of insulin.
  • Increased insulin secretion causes the kidneys to retain salt and water. Salt and excess fluids are reabsorbed.
  • With excess salt and fluid retention, swelling may appear in the most gravity-dependent parts of the body. If the individual sits down, the buttocks may swell. If the individual is sleeping on their back, the bottom area of the body will swell.
  • This condition will normalize with time, but it can be uncomfortable, lasting days or weeks.
  • The weight gain and visible changes in body size associated with fluid retention can be particularly distressing for patients during this phase since many fear weight gain, suffer from body image concerns or have body dysmorphia.

To alleviate discomfort, the providers may recommend that patients elevate their legs or use compression stockings, in more severe cases, during refeeding. While edema is uncomfortable, it is not fatal.

Fortunately, this type of edema will resolve with continued management of refeeding. The body will adjust to both the changes in insulin secretion and salt and fluid retention, stabilizing itself over time.

PseudoBartter Syndrome

Individuals with a history of purging behavior, individuals with low serum albumin and/or individuals who spend a significant amount of the day standing are at risk for PseudoBartter Syndrome.

  1. Purging leads to intravascular depletion (reduced blood volume), increasing the risk for syncope and reducing the blood flow to the kidneys.
  2. Reduced blood flow to the kidneys ultimately stimulate the adrenal glands to increase production of a hormone called aldosterone.
  3. Aldosterone causes the kidneys to retain salt and water, helping to maintain blood pressure and intravascular volume. This is great as it helps to reduce risk of syncope but this is not so great during the refeeding process or if patients receive IV fluids.
  4. The salt and water retention due to aldosterone can be quite aggressive.

Treatment for this condition first includes cessation of purging, normalization of serum potassium values, and normalization of intravascular volume. Spironolactone, a medication to block the effects of aldosterone, can be utilized, and sometimes a second diuretic is warranted to combat aggressive weight trends.

This condition can cause a large amount of emotional distress after an individual stops a long-standing pattern of purging. In fact, the edema may be so upsetting that the individual may question recovery and want to start purging again. Patients need to be reassured that pseudoBartter syndrome is part of the healing process and that the edema will resolve with appropriate treatment and time.

Providers should check blood and urine tests frequently and administer spironolactone and additional diuretics as needed. Patients should be aware that this process can often take weeks. Patients who engage in frequent purging should seek medically supervised refeeding with eating disorder treatment experts.

Edema with Refeeding Syndrome

Individuals with anorexia nervosa, avoidant restrictive food intake disorder (ARFID) or malnutrition from other causes are all at risk for edema with refeeding syndrome. Individuals with severe eating disorders or malnutrition who are undergoing refeeding can experience edema as part of refeeding syndrome, a serious and potentially fatal complication that can occur during nutritional rehabilitation. The biggest risk factor for refeeding syndrome is malnutrition, with low BMI conferring a significant risk. Development of hypophosphatemia is a necessary step in the development of refeeding syndrome, although refeeding hypophosphatemia and refeeding syndrome are not the same entity.

Refeeding syndrome occurs in significantly malnourished patients when they are given a diet of increasing calories orally, by nasogastric (NG) tube or intravenously, and electrolytes are not adequately monitored. Carbohydrate ingestion causes insulin release, which causes cellular uptake of phosphorous and other electrolytes. Cellular dysfunction can develop with adequate phosphorous, due to reduced production of ATP, ultimately leading to organ dysfunction. Compromised cardiovascular status can lead to congestive heart failure, causing edema formation.

Once refeeding syndrome is observed, it requires immediate medical intervention. At ACUTE, providers keep a close eye on all patients to ensure adequate phosphorous stores are present; providers constantly monitor each patient’s heart health, electrolytes, especially phosphorous levels, and more. To reduce the risk of refeeding syndrome, all care providers initiating nutritional rehabilitation should do so in an inpatient medical setting that specializes in preventing, identifying and managing refeeding syndrome. As concerning as this condition is, the development of refeeding syndrome is predictable and the best treatment for refeeding syndrome is prevention.

Edema Due to Low Albumin Levels

Individuals with an underlying inflammatory state are at risk for edema due to low albumin levels. Albumin is a key protein circulating in the blood stream that is made in the liver. Albumin is required to prevent fluid from leaking out of blood vessels.  When albumin drops to a low level (hypoalbuminemia), fluid can leak out of blood vessels and into body tissues, resulting in edema. Inflammation causes a decrease in albumin levels through various mechanisms. The risk for hypoalbuminemia is not increased when individuals are engaging in eating disorder behaviors and, contrary to popular belief, malnutrition does not seem to increase the risk of hypoalbuminemia.  Rather, when hypoalbuminemia is identified, it should prompt one to look for other medical conditions. Detection of hypoalbuminemia at ACUTE often results in additional medical tests.

Management of hypoalbuminemia includes the following:

  • Treatment of the underlying inflammatory condition(s), if diagnosed
  • Managing associated complications such as edema
  • Optimizing nutritional status in all patients with this condition

The discomfort and weight gain associated with edema can cause a great deal of physical and medical anguish for those in eating disorder recovery. Most medical providers are not trained to identify and treat edema associated with refeeding syndrome and the other medical conditions listed above. This unfortunate reality underscores the need for severely underweight patients to begin the refeeding process in an inpatient medical setting capable of treating the most serious eating disorders.


Last Reviewed: December 2023 by Dennis Gibson, MD, FACP, CEDS

Written by

Kristin Anderson, MD

Dr. Kristin Anderson was born and raised in the great Hawkeye state of Iowa. She received both her bachelors of science in biomedical engineering and her medical doctorate degree from the University…

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