NAPLEX Question of the Week: Nutrition

This week we hit a major topic within nutrition that is critical.

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Nov 14, 2019
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BD is a 68-year-old woman with cancer cachexia. She has lost 10% of her body weight since her diagnosis with colon cancer about 6 months ago. Her cancer treatments are causing severe nausea and vomiting. The physician wants to start parenteral nutrition. The dietitian expresses concern regarding refeeding syndrome. Which electrolyte abnormalities are characteristic of this syndrome? Select all that apply.

a. Hypomagnesemia

b. Hypercalcemia

c. Hypokalemia

d. Hypophosphatemia







Answers with Rationale:

Refeeding syndrome occurs in the setting of chronic malnutrition when a patient is refed with aggressive amounts of dextrose. Although more likely to occur with parenteral feeding, it has also been reported with enteral and oral feedings. In extreme cases, it can be associated with pulmonary and cardiac failure and central nervous system involvement which can be life threatening.

Answer a is correct. Although hypophosphatemia is the hallmark electrolyte abnormality of refeeding syndrome, hypokalemia and hypomagnesemia may also occur as outlined under answer d below.

Answer b is incorrect. Although hypercalcemia is common in patients with cancer, it is not the hallmark of refeeding syndrome.

Answer c is correct.  Although hypophosphatemia is the hallmark electrolyte abnormality of refeeding syndrome, hypokalemia and hypomagnesemia may also occur as outlined under answer d below.

Answer d is correct. With carbohydrate refeeding, phosphorus, magnesium, and potassium, which are primarily intracellular electrolytes, are forced intracellularly by the action of insulin. This leads to lower levels of these electrolytes in the extracellular space, including the blood, where levels are routinely measured. Therefore, hypophosphatemia, hypomagnesemia, and hypokalemia are expected with refeeding. Hypophosphatemia is the hallmark electrolyte abnormality. Phosphorus is important in diaphragm function and in energy metabolism as a component of adenosine triphosphate (ATP). Thus hypophosphatemia can contribute to respiratory failure in severe refeeding syndrome.

See everyone next week!

Dr. B

Go to the profile of Christopher M. Bland

Christopher M. Bland

Clinical Associate Professor, University of Georgia College of Pharmacy

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