American Board of Internal Medicine (ABIM) Certification Practice Exam

What can intravenous dextrose-containing fluids exacerbate by promoting insulin release?

1. Hypercalcemia

2. Hypophosphatemia

3. Hyponatremia

4. Hypokalemia

The correct answer is: Hypophosphatemia

Intravenous dextrose-containing fluids can exacerbate hypophosphatemia primarily due to their role in stimulating insulin release. When dextrose is administered, it leads to increased glucose levels in the bloodstream, triggering the pancreas to release insulin. Insulin plays a vital role in cellular metabolism and also influences phosphate metabolism. As insulin facilitates the uptake of glucose into cells, it simultaneously promotes the uptake of phosphate, leading to a decrease in the serum phosphate levels. This can be particularly pronounced in individuals who are already at risk of hypophosphatemia, such as those who are malnourished, experiencing refeeding syndrome, or have other metabolic disturbances. Consequently, the administration of dextrose-containing fluids not only provides carbohydrates but also can inadvertently cause a further drop in serum phosphate levels, resulting in hypophosphatemia. Understanding the physiological relationship between insulin, glucose, and phosphate can help in managing patients receiving intravenous dextrose to avoid complications associated with low phosphate levels.