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Refeeding Syndrome

Created: 21/5/2007
Updated: 21/5/2007

Refeeding Syndrome

Gina Tomlin
Chief dietician, John Radcliffe Hospital, Oxford

Focus on refeeding syndrome – ‘feeding the malnourished patient’

The refeeding syndrome is defined as the metabolic abnormalities that occur upon refeeding a person in a starved state (Figure 1).

Metabolic consequences include:

  • Hypophosphataemia
  • Hypokalaemia
  • Hypomagnesaemia
  • Fluid balance abnormalities

The metabolic abnormalities can lead to significant pathophysiological consequences.

Pathophysiological consequences include:

  • Cardiac failure
  • Respiratory failure
  • Neuromuscular failure
  • Renal failure
  • Haematological failure
  • Hepatic failure
  • Gastrointestinal system failure

As thiamine acts as a coenzyme in carbohydrate metabolism, the symptoms of Wernike’s encephalopathy can occur by refeeding carbohydrate to a vitamin B depleted patient.

Figure 1. The Pathogenesis of Refeeding Syndrome


Conversion to glucose as major energy source

Insulin release*

­ cellular glucose uptake, ­ protein synthesis

Intracellular shifts and extracellular depletion of phosphate, potassium and magnesium

Clinical symptoms of refeeding syndrome


* Insulin release stimulates the Na+K+ATPase pump (which requires magnesium as a cofactor). This drives potassium into the cells and sodium moves out. Carbohydrate load and insulin release stimulate phosphate shifts into the cells and phosphate depletion is associated with increased urinary magnesium excretion. These phenomena lead to low extracellular phosphate, magnesium and potassium, and may precipitate the symptoms of refeeding syndrome.

Focus on patients at risk of refeeding syndrome

Patients at risk of refeeding syndrome include:

  • Chronic alcoholics
  • Drug abusers
  • The chronically malnourished (particulary the elderly)
  • Patients with anorexia nervosa
  • Patients with prolonged nil by mouth or fasting times coupled with depletion or physiological stres.

The risk of an individual patient for refeeding syndrome has been further classified:

Moderate Risk

Patient has one or more of the following:

  1. BMI less than 18.5kg/m2
  2. Unintentional weight loss greater than 10% within the previous 3-6 months
  3. Very little intake for greater than 5 days

High Risk

Patient has one or more of the following:

  1. BMI less than 16kg/m2
  2. Unintentional weight loss greater than 15% within the previous 3-6 months
  3. Very little nutritional intake for greater than 10 days
  4. Low levels of potassium, phosphate or magnesium prior to feeding

Or patient has two or more of the following:

  1. BMI less than 18.5kg/m2
  2. Unintentional weight loss greater than 10% within the previous 3-6 months
  3. Those with very little intake for greater than 5 days
  4. A history of alcohol abuse or drugs including insulin, chemotherapy, antacids or diuretics

Severely High Risk

Patient has both of the following

  1. BMI less than 14
  2. Negligible intake for greater than 15 days

Focus on how to start feeding patients at risk of refeeding syndrome

The overall aim is to start refeeding slowly, supplement thiamine and aggressively replace any electrolyte disturbances. ESPEN guidelines (2006) recommend starting enteral nutrition early (<24hrs post admission to ICU) in those haemodynamically stable and who have a functioning gastrointestinal tract. Parenteral nutrition should be started if unable to meet nutritional requirements via the enteral route (Figure 2).

Figure 2. Example of a refeeding syndrome flow chart

Determine level of re-feeding risk
Check baseline potassium, calcium, phosphate and magnesium levels
Replete electrolytes as indicated

Replete thiamine

Start feeding at 20 kcal/kg Moderate Risk

Start feeding at 10kcals/kg High Risk

Start feeding at 5kcal/kg  Severely High Risk

Do not wait for electrolyte blood level to be within normal range before slowly starting feeding

Repeat potassium, magnesium, calcium and phosphate levels 6-12hrs after initiation of feeding

Replace electrolytes as required. If patient requires more than 2 electrolyte replacements check urinary (24hour collection) magnesium, phosphate and potassium. Inform Dietician to alter feed rate as required

Monitor potassium, magnesium, phosphate and calcium daily for 1st 3 days or until levels within normal ranges, then 3 times a week for 2 weeks

MONITORING the severely at risk – Restore circulatory volume and monitor fluid balance and overall clinical status closely. Monitor cardiac rhythm continually in these patients and any other who develop cardiac arrhythmias (NICE 2006)

Key References

Soloman S, Kirby D.
The Refeeding syndrome: A review.
Journal of parenteral and enteral nutrition. 1990; 14(1): 90-97.

Brooks MJ, Melnick, G.
The refeeding syndrome: an approach to understanding its complications and preventing its occurrence.
Pharmacotherapy 1995; 15: 713-26.

Crook M, Hally V, Panteli J.
The importance of the refeeding syndrome.
Nutrition 2001. 17. 632-7.

Hearing SD. Refeeding syndrome.
BMJ 2004; 328: 908-9.

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