A nurse is caring for a patient who has nephrotic syndrome and is receiving high-dose corticosteroid therapy. For which of the following electrolyte imbalances should the nurse monitor?

Choice A rationale High-dose corticosteroid therapy, such as with prednisone, can cause hypokalemia by increasing potassium excretion in the kidneys. These steroids mimic the action of aldosterone, which promotes sodium reabsorption and potassium excretion in the distal convoluted tubules and collecting ducts. This process leads to increased urinary loss of potassium, potentially causing a serum potassium level below the normal range of 3.5 to 5.0 mEq/L. Choice B rationale Hypermagnesemia is not a typical side effect of corticosteroid therapy. Corticosteroids primarily affect sodium and potassium balance. Hypermagnesemia is more commonly associated with kidney failure or excessive intake of magnesium-containing medications. The kidneys are highly efficient at excreting magnesium, so elevated levels (normal range 1.5 to 2.5 mEq/L) are rare unless renal function is compromised. Choice C rationale Corticosteroid therapy actually increases the excretion of potassium from the body, leading to a decrease in serum potassium levels, not an increase. The mineralocorticoid effects of these drugs cause increased activity of the sodium-potassium pump in renal tubules, leading to the exchange of potassium for sodium, resulting in increased urinary potassium loss and a risk for hypokalemia. Choice D rationale While some electrolyte imbalances can occur, hypomagnesemia is not a primary concern directly linked to high-dose corticosteroid therapy. Corticosteroids' main effect on electrolytes is their mineralocorticoid activity, which primarily targets sodium and potassium regulation. Hypomagnesemia is more commonly associated with conditions like chronic alcoholism, malnutrition, or gastrointestinal losses.