uk-fficm MCQ (SBA): Refeeding Syndrome

A 50-year-old woman on ICU has been receiving enteral nutrition via a nasogastric tube for 5 days. She has been receiving 1500 kcal/day. She develops diarrhoea, confusion, hypophosphataemia (0.35 mmol/L), hypokalaemia (2.8 mmol/L), and hypomagnesaemia (0.5 mmol/L). She was malnourished on admission with a BMI of 16. What is the most likely diagnosis?