Clinical Scenario:
A 3-year-old girl with severe acute malnutrition is admitted with lethargy and poor appetite. Her weight-for-height is −3.8 Z-scores and she has bilateral pedal edema. After initial stabilization, therapeutic feeding is started cautiously.
On the third day, she becomes increasingly weak and tachypnoeic. She develops peripheral edema and a new irregular tachycardia. Blood glucose is normal. Investigations show:
- Phosphate: 0.45 mmol/L
- Potassium: 2.8 mmol/L
- Magnesium: 0.55 mmol/L
She had no significant electrolyte abnormality before feeding was started.
Which of the following best explains her deterioration?
A. Acute heart failure from excessive intravenous fluids
B. Refeeding syndrome
C. Sepsis-induced myocardial dysfunction
D. Vitamin B1 deficiency alone
E. Worsening protein-energy malnutrition
Correct answer & Explanation:
Correct answer: B. Refeeding syndrome
Explanation
This child has refeeding syndrome, a potentially serious complication that can occur when nutrition is restarted in a severely malnourished patient.
During prolonged starvation, insulin levels are low and the body adapts to using fat and protein as energy sources. When carbohydrate-containing nutrition is restarted, insulin secretion rises, driving phosphate, potassium and magnesium into cells for ATP production and cellular metabolism. Consequently, serum concentrations can fall rapidly.
The most characteristic biochemical abnormality is hypophosphatemia. In this child, the marked fall in phosphate, together with hypokalemia and hypomagnesemia after feeding was initiated, strongly supports refeeding syndrome.
The clinical consequences can include:
- Muscle weakness and respiratory failure due to impaired energy production
- Cardiac dysfunction and arrhythmias
- Peripheral edema from sodium and fluid retention
- Neurological manifestations such as confusion or seizures
- In severe cases, cardiac failure and death
Why the timing is important:
The child deteriorates on the third day after nutritional rehabilitation, which is typical of refeeding syndrome. The electrolyte abnormalities were not present before feeding, making the temporal relationship particularly important.
Key postgraduate point:
In a severely malnourished child, nutrition must be restarted cautiously with close monitoring of phosphate, potassium and magnesium, particularly during the early days of nutritional rehabilitation. Refeeding syndrome should be suspected when hypophosphatemia develops after feeding is initiated.
References
da Silva JSV, Seres DS, Sabino K, et al. ASPEN Consensus Recommendations for Refeeding Syndrome. Nutrition in Clinical Practice. 2020;35(2):178–195. This consensus specifically includes pediatric patients and identifies reductions in phosphate, potassium and/or magnesium within 5 days of restarting calories as the basis for diagnosing and grading refeeding syndrome.
