Refeeding Syndrome
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Direct answer
Refeeding syndrome is a potentially fatal shift of electrolytes and fluid that occurs when nutrition is restarted after prolonged starvation or very poor intake. Insulin release on carbohydrate reintroduction drives phosphate, potassium and magnesium into cells, producing hypophosphataemia, hypokalaemia and hypomagnesaemia. Thiamine deficiency can precipitate Wernicke encephalopathy, so prevention rests on risk screening, thiamine before feeding and slow, staged calorie increases.
What you must remember
- Risk features (NICE): BMI below 16, unintentional weight loss over 15 per cent in three to six months, little or no intake for over 10 days, or low potassium, phosphate or magnesium before feeding.
- Mechanism: insulin released after carbohydrate restart drives phosphate, potassium, magnesium and thiamine into cells, lowering their serum levels.
- Hypophosphataemia: the characteristic finding, causing muscle weakness, respiratory failure, haemolysis, rhabdomyolysis and cardiac dysfunction.
- Thiamine: given before any calories and continued during refeeding, because carbohydrate metabolism raises thiamine demand and Wernicke encephalopathy can follow.
- Prevention: start at a reduced energy intake, commonly about 10 kcal per kg per day in high-risk adults, and advance over several days while correcting electrolytes.
- Indian setting: children with severe acute malnutrition, patients with anorexia nervosa or alcohol dependence, and people recovering from prolonged starvation are the typical groups.
Restarting nutrition in a starved patient
A 52-year-old man with alcohol dependence has eaten almost nothing for 12 days and is about to be started on artificial nutrition. His electrolytes must be watched closely because the risk rises as soon as feeding begins.
- Identify risk early: Screen every patient on admission for BMI, weight history, intake and alcohol use, and measure phosphate, potassium and magnesium.
- Give thiamine first: Start thiamine before any calories, and continue it through the feeding period.
- Start low: Begin at a reduced energy intake, and advance over several days rather than meeting full requirements on day one.
- Replace electrolytes: Correct hypophosphataemia, hypokalaemia and hypomagnesaemia before and during feeding, since levels can fall quickly.
- Monitor closely: Check phosphate, potassium, magnesium and fluid balance daily through the first several days of refeeding.
- Watch for complications: Respiratory weakness, heart failure, seizures, delirium or Wernicke signs need urgent review and electrolyte correction.
Where the exam tries to catch you
Refeeding questions test timing: what to give first, how fast to advance and which electrolyte falls.
- Trap: meeting full calorie needs on day one to catch up quickly. Correct: rapid feeding in high-risk patients precipitates refeeding syndrome, so intake rises gradually.
- Trap: giving glucose before thiamine in a malnourished patient. Correct: glucose can precipitate Wernicke encephalopathy in thiamine-deficient patients, so thiamine comes first.
- Trap: assuming normal electrolytes on admission exclude risk. Correct: the starvation history defines risk, and the phosphate fall often appears only after feeding begins.
Frequently asked questions
Which electrolyte abnormality is most characteristic of refeeding syndrome?
Hypophosphataemia is the most characteristic electrolyte abnormality of refeeding syndrome, and it drives the muscle, cardiac and respiratory complications. Hypokalaemia and hypomagnesaemia commonly occur alongside it.
Why is thiamine given before feeding in refeeding syndrome?
Thiamine is given before feeding because carbohydrate restart increases thiamine demand, which can precipitate Wernicke encephalopathy in deficient patients. Thiamine is therefore started before calories and continued throughout refeeding.
What are the NICE high-risk features for refeeding syndrome?
NICE high-risk features for refeeding syndrome include BMI below 16, unintentional weight loss over 15 per cent in three to six months, and little or no nutritional intake for more than 10 days. Low potassium, phosphate or magnesium before feeding also marks high risk.
Why does insulin release cause refeeding syndrome?
Insulin released on carbohydrate reintroduction drives phosphate, potassium, magnesium and thiamine into cells. This intracellular shift lowers serum levels in refeeding syndrome and precipitates the electrolyte disturbances that cause harm.
Where is refeeding syndrome seen in Indian clinical practice?
Refeeding syndrome is seen in children with severe acute malnutrition, in patients with anorexia nervosa or alcohol dependence, and after famine or prolonged illness. Staged feeding protocols, such as the WHO F-75 starting phase for children, reflect this risk.