Parenteral nutrition and refeeding syndrome — formative SAQs

SAQ 1 — The malnourished adolescent restarted on feeding (10 marks, 15 minutes)

A 15-year-old girl with anorexia nervosa is admitted for refeeding after six weeks of negligible intake and a 15 per cent weight loss. Her body mass index is 15. On day two of a refeeding regimen the phosphate has fallen, she is oedematous, and her heart rate is rising. [5]

a) Define refeeding syndrome and explain the biochemical mechanism by which restarting carbohydrate drives phosphate, potassium and magnesium into the cell and depletes thiamine. (3 marks) [5] [6]

b) Identify the features in this history that place her at high risk of refeeding syndrome, using the ASPEN consensus risk stratification. (2 marks) [5]

c) Outline the prevention and management you should have instituted before and during refeeding, naming thiamine, conservative starting calories, and the correction and monitoring of phosphate, potassium and magnesium. (3 marks) [5] [6]

d) Explain why she has become oedematous with a rising heart rate, and state the immediate response. (2 marks) [6]

SAQ 2 — The preterm infant with rising conjugated bilirubin (10 marks, 15 minutes)

A baby born at 27 weeks gestation has been on parenteral nutrition for four weeks for an immature gut that tolerates little milk. The lipid has been running at 3 g/kg/day from a soy-based emulsion, there have been two central-line bloodstream infections, and the conjugated bilirubin is now rising. [9]

a) Name the four parenteral streams, and give the infant targets for the glucose infusion rate, the amino acid and the lipid streams, and the energy. (3 marks) [1] [3]

b) What is the likely diagnosis for the rising conjugated bilirubin, and what are the two dominant modifiable drivers? (2 marks) [8] [9]

c) Outline the lipid and sepsis strategy to prevent and treat this condition, including the regional differences in preferred emulsion. (3 marks) [2] [8]

d) State what other diagnosis must be actively excluded in any cholestatic infant, and how. (2 marks) [8]