What is the pathophysiology and clinical management of refeeding syndrome?

From the Guidelines

Refeeding syndrome can be prevented by introducing nutrition gradually, starting at about 10 kcal/kg/day, with close monitoring of electrolytes and supplementation of phosphate, potassium, magnesium, and thiamine, as recommended by the most recent guidelines 1. To prevent refeeding syndrome, it is essential to identify patients at high risk, including those with anorexia nervosa, chronic alcoholism, prolonged fasting, or significant weight loss. The syndrome develops due to rapid shifts in fluids and electrolytes, particularly phosphate, potassium, and magnesium, which drop dramatically when carbohydrate intake increases, triggering insulin release. This causes these electrolytes to move from blood into cells, leading to potentially life-threatening complications including heart failure, respiratory failure, seizures, and death.

Key Recommendations

• Start nutrition at a low level, approximately 10 kcal/kg/day, and increase slowly over 4-7 days 1
• Monitor electrolytes closely, including potassium, phosphate, and magnesium, and supplement as needed 1
• Provide thiamine supplementation, 200-300 mg daily, to prevent deficiency 1
• Consider multidisciplinary management involving nutrition specialists, medical providers, and sometimes intensive care for high-risk patients 1

Patient Screening

Patients at high risk of refeeding syndrome should be screened using the following criteria:

• BMI <16 kg/m2
• Unintentional weight loss >15% in 3-6 months
• Little or no intake for >10 days
• Low potassium, phosphate, and magnesium before feeding 1 If two or more of these factors exist, a risk of refeeding syndrome should be considered, and preventive measures should be taken.

From the Research

Definition and Causes of Refeeding Syndrome

• Refeeding syndrome is a potentially lethal complication of refeeding in patients who are severely malnourished from whatever cause 2.
• It occurs when feeding is commenced after a period of starvation, particularly in patients with prolonged periods of poor nutritional intake 3.
• The syndrome is caused by rapid refeeding after a period of under-nutrition, characterized by hypophosphataemia, electrolyte shifts, and metabolic and clinical complications 3.

Risk Factors and Patient Identification

• High-risk patients include the chronically under-nourished and those with little intake for greater than 10 days 3.
• Patients with dysphagia are at particular risk, especially head and neck cancer patients 3.
• A high clinical suspicion is necessary when refeeding any malnourished patient, including those who have had no or very little nutrition for over 5 days 4.

Prevention and Treatment

• Refeeding should commence at 10 kcal/kg per day in patients at risk, and increased slowly 3.
• Thiamine, vitamin B complex, and multi-vitamin supplements should be started with refeeding 3.
• Generous vitamin and electrolyte supplementation may be given while monitoring closely and increasing the calorie intake reasonably rapidly from 10 to 20 kcal/kg/24 hours 4.
• A consensus statement is available, providing guidance from experts in the field on the management of patients at increased risk of refeeding syndrome receiving nutritional therapy 5.

Clinical Complications and Management

• The main clinical problems may relate to hypophosphataemia, hypomagnesaemia, and hypokalaemia with a risk of sudden death 4.
• Thiamine deficiency with the risk of Wernike's encephalopathy/Korsakoff psychosis and sodium/water retention are also potential complications 4.
• If problems do occur, the feed should be slowed to the previous day's amount, reduced further, or rarely stopped while fluid and electrolyte issues are corrected 4.
• Every patient should undergo a risk assessment for refeeding syndrome and stratification before starting nutritional therapy 5.