A 69-year-old male, body mass index 17.5 kg/m2, is commenced on total parenteral nutrition (TPN) following surgery for a gastric malignancy. Four days later he develops increasing breathlessness and hypotension. Blood results are as follows:

 

Test

Value

Normal Adult Range

Haemoglobin*

109 G/L

115 – 155

White Cell Count*

13.6 x 109 /L

4.0– 11.0

Platelets

178 x 109 /L

150 – 400

Urea*

10.3 mmol/L

3.0– 8.0

Creatinine

84 µmol/L

45– 90

Sodium

145 mmol/L

134 – 146

Potassium*

1.8 mmol/L

3.4– 5.0

Chloride*

115 mmol/L

98– 108

Bicarbonate*

14 mmol/L

22– 32

Calcium (albumin

adjusted)*

1.82 mmol/L

2.15 – 2.6

Albumin*

26 G/L

35– 50

Magnesium*

0.41 mmol/L

0.7– 1.1

Phosphate inorganic*

0.26 mmol/L

0.8– 1.5

Glucose*

18.6 mmol/L

3.0– 5.4
  • What is the likely diagnosis?
  • Give four reasons that support your answer.

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College Answer

Refeeding syndrome (Nutritional recovery syndrome).

  • Clinical history
  • Low PO4
  • Profound hypokalaemia
  • Hypomagnesaemia

Discussion

An underweight elderly gentleman gets TPN after a prolonged period of malnutrition. It does not take a massive cognitive effort to recognise refeeding syndrome, given the hypokalemia and hypophosphataemia.

Refeeding syndrome is discussed in greater detail elsewhere.

Its typical biochemical features are:

  • Hypophosphatemia
  • Hypomagnesemia
  • Hypokalemia

Lesser known abnormalities include:

  • Thiamine depletion
  • Depletion of micronutrients (eg. selenium, copper and zinc)
  • Hypernatremia (with protein-dominant nutritional replacement)
  • Hyponatremia (with carbohydrate-dominant nutritional replacement)

The shortness of breath and hypotension in this case are likely to a combination of low phosphate and fluid overload in the context of myocardial atrophy. Arrhythmia and respiratory muscle weakness cannot be ruled out.

References

Hearing, Stephen D. "Refeeding syndrome." BMJ 328.7445 (2004): 908-909.

Stanga, Z., et al. "Nutrition in clinical practice—the refeeding syndrome: illustrative cases and guidelines for prevention and treatment." European journal of clinical nutrition 62.6 (2008): 687-694.

Kraft, Michael D., Imad F. Btaiche, and Gordon S. Sacks. "Review of the refeeding syndrome." Nutrition in Clinical Practice 20.6 (2005): 625-633.

Khan, Laeeq UR, et al. "Refeeding syndrome: a literature review."Gastroenterology research and practice 2011 (2010).