Synopsis
Identify patients vulnerable to refeeding before calories increase, start nutrition and vitamins safely, and detect phosphate, potassium, magnesium, thiamine and fluid complications early.
- Refeeding syndrome is the potentially fatal fluid, electrolyte and vitamin disturbance that follows renewed nutrition after depletion; oral food, supplements, tube feed, PN and intravenous dextrose can all contribute.
- Carbohydrate-driven insulin release shifts phosphate, potassium and magnesium into cells, increases thiamine use and promotes sodium and water retention, impairing cardiac, respiratory and neurological function.
- NICE high risk includes any one of BMI below 16, weight loss above 15% in three to six months, minimal intake beyond ten days, or low pre-feeding potassium, phosphate or magnesium.
- Risk also exists with two or more of BMI below 18.5, weight loss above 10%, little or no intake beyond five days, or alcohol or relevant drug history such as insulin, chemotherapy, antacids or diuretics.
- For high-risk adults, NICE advises starting nutrition at no more than 10 kcal/kg/day, or 5 kcal/kg/day in extreme cases, then increasing gradually over four to seven days.
- Give thiamine immediately before and during early feeding, provide balanced vitamin support, replace potassium, phosphate and magnesium and plan close clinical and biochemical surveillance.
- Pre-feeding electrolyte deficits are generally replaced alongside cautious nutrition rather than using complete normalisation as a reason for prolonged starvation; severe symptomatic abnormalities still require urgent senior management.
- Count every source of energy and fluid, including dextrose infusions, propofol lipid, supplements and medication carriers, and involve clinicians skilled in nutrition support for high-risk care.
Key red flags
Arrhythmia, syncope, chest pain, hypotension or acute heart failure after feeding starts requires immediate monitoring, electrolyte assessment and senior resuscitation support.
Respiratory weakness, increasing oxygen requirement or failure to wean ventilation can result from profound phosphate depletion and needs urgent critical-care evaluation.
Confusion with ophthalmoplegia, ataxia, hypothermia or reduced consciousness should be treated as possible Wernicke encephalopathy without waiting for a thiamine assay.
Seizure, tetany, severe weakness or rhabdomyolysis suggests dangerous electrolyte disturbance requiring rapid monitored correction and investigation of concurrent causes.
Rapid weight gain, peripheral oedema, oliguria or pulmonary crackles signals maladaptive sodium and water retention, especially hazardous in cardiac or renal disease.
Investigation priorities
Classify vulnerability before any meaningful rise in energy delivery.
Management branches
A depleted or recently underfed patient is about to receive additional oral, enteral or parenteral energy.
- Obtain reliable recent intake, weight-loss percentage, BMI, alcohol and medicine history, comorbidity and baseline potassium, phosphate, magnesium, glucose and renal function.
- Identify high or extreme risk using NICE criteria and notify the responsible nutrition-experienced clinician before calories are prescribed.
- Give thiamine and balanced vitamin support immediately before feeding and plan electrolyte replacement, fluid restriction or cardiac monitoring as indicated.
- Write a single prescription covering all calorie and fluid sources, starting intensity, laboratory frequency and named escalation thresholds.