Overview
Refeeding syndrome describes the potentially fatal metabolic disturbances that can occur following refeeding in patients who are malnourished, starved, or stressed due to severe illness. It usually occurs within 4 days of refeeding.
Pathophysiology
In starvation, insulin secretion is decreased due to reduced carbohydrate intake and fat and proteins are catabolised to release energy. This leads to an intracellular loss of electrolytes, particularly phosphate, magnesium, and potassium.
When feeding restarts, the shift from fat and protein to carbohydrate metabolism increases insulin secretion, which stimulates cellular uptake of phosphate and other electrolytes, leading to severe hypophosphataemia, hypokalaemia, and hypomagnesaemia. Phosphate is essential for the formation of ATP and other phosphorylation reactions, leading to cellular dysfunction.
Risk Factors
Patients are deemed at high risk of refeeding syndrome if:
- 1 or more of the following are present:
- BMI less <16 kg/m2
- Unintentional weight loss greater than 15% within the last 3 to 6 months
- Little or no nutritional intake for more than 10 days
- Low levels of potassium, phosphate or magnesium before feeding
- Or 2 or more of the following apply:
- BMI less than 18.5 kg/m2
- Unintentional weight loss greater than 10% within the last 3 to 6 months
- Little or no nutritional intake for more than 5 days
- A history of alcohol abuse or drugs including insulin, chemotherapy, antacids or diuretics
Presentation
Features may include:
- Hypophosphataemia
- Hypokalaemia
- Hypomagnesaemia
- Features of Wernicke-Korsakoff encephalopathy (due to thiamine deficiency)
- Hyperglycaemia – due to abnormal glucose metabolism and reduced insulin secretion
- Cardiac arrhythmia – due to electrolyte imbalances
- Fluid imbalances
- Pulmonary oedema
- Heart failure
Management
In general:
- Initiate feeding at no more than 50% of energy in patients who have eaten little or nothing for more than 5 days, then increase if no refeeding problems are detected on clinical or biochemical testing
- Electrolyte levels are checked once daily for 1 week then at least 3 times in the following week
