What is refeeding syndrome?

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From the Guidelines

Refeeding syndrome is a potentially life-threatening condition that occurs when nutrition is reintroduced too quickly after a period of starvation or severe malnutrition, characterized by dangerous shifts in fluids and electrolytes, particularly phosphate, potassium, and magnesium, which can lead to serious complications including heart failure, respiratory failure, seizures, coma, and even death. This syndrome typically develops within the first few days of refeeding when the body rapidly shifts from a catabolic to an anabolic state, causing insulin release that drives electrolytes into cells and depletes circulating levels 1. Patients at highest risk include those with anorexia nervosa, chronic alcoholism, prolonged fasting, uncontrolled diabetes, or those who have undergone prolonged periods without adequate nutrition.

Prevention and Management

Prevention involves careful refeeding with gradual caloric increases, close monitoring of electrolytes, and appropriate supplementation before and during refeeding. The most recent guidelines recommend initiating nutrition support slowly, with 5–10 kcal/kg for the first 24 h, and monitoring serum electrolytes (potassium, magnesium, and phosphorous) both before the initiation of nutrition and at least every frequently for the first 3 days thereafter and longer if electrolyte abnormalities persist 1.

Key Considerations

  • Electrolyte Monitoring and Supplementation: Aggressive electrolyte repletion and cardiorespiratory monitoring are recommended to avoid cardiac dysrhythmias.
  • Thiamine Supplementation: Thiamine (vitamin B1) supplementation of 200-300mg daily is also crucial to prevent Wernicke's encephalopathy.
  • Glycemic Control: Hyperglycemia is common in ICU patients receiving nutritional support, and guidelines recommend a target blood glucose of 140–180 mg/dL (7.8–10 mmol/L) and avoidance of prolonged hypoglycemia.

Conclusion Not Applicable

Instead, focusing on the key aspects of refeeding syndrome:

  • It is a life-threatening condition that requires careful management.
  • The physiological basis lies in the body's adaptation to starvation and the subsequent shift to an anabolic state upon refeeding.
  • Prevention and management strategies are crucial to avoid serious complications.

Given the most recent evidence from 1, the approach to refeeding syndrome should prioritize gradual refeeding, close monitoring, and appropriate supplementation to mitigate risks and improve patient outcomes.

From the Research

Definition of Refeeding Syndrome

Refeeding syndrome (RFS) is a group of clinical findings that occur in severely malnourished individuals undergoing nutritional support, characterized by fluid and electrolyte imbalances, with hypophosphatemia playing a central role 2. It is a potentially lethal complication of refeeding in patients who are severely malnourished from whatever cause 3.

Clinical Manifestations

The clinical manifestations of refeeding syndrome include:

  • Cardiac arrhythmias
  • Multisystem organ dysfunction
  • Death
  • Electrolytic alterations, such as:
    • Hypomagnesemia
    • Hypokalemia
    • Hypophosphatemia
  • Fluid retention
  • Vitamin deficiency
  • Metabolic acidosis 4, 5, 3, 6

Prevention and Treatment

The most effective means of preventing or treating refeeding syndrome are:

  • Recognizing patients at risk
  • Providing adequate electrolyte, vitamin, and micronutrient supplementation
  • Careful fluid resuscitation
  • Cautious and gradual energy restoration
  • Monitoring of critical laboratory indices 2, 5, 3 It is essential to establish an initial caloric amount that will stimulate weight gain from the beginning of treatment, increase its effectiveness while minimizing the risk of refeeding syndrome 6.

Risk Factors

Patients at risk for refeeding syndrome include those with severe malnutrition, anorexia nervosa, and those undergoing enteral or parenteral nutrition 4, 6. Awareness of the risks associated with refeeding syndrome, including significant mortality, appears to be currently insufficient among physicians 6.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Review of the refeeding syndrome.

Nutrition in clinical practice : official publication of the American Society for Parenteral and Enteral Nutrition, 2005

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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