Fluid & Electrolyte Q 80

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Joshua is receiving furosemide and Digoxin, which laboratory data would be the most important to assess in planning the care for the client?

  

    A. Sodium level

    B. Magnesium level

    C. Potassium level

    D. Calcium level

    

    

Correct Answer: C. Potassium level

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Diuretics such as furosemide may deplete serum potassium, leading to hypokalemia. When the client is also taking digoxin, the subsequent hypokalemia may potentiate the action of digoxin, placing the client at risk for digoxin toxicity. Most cases of hypokalemia result from gastrointestinal (GI) or renal losses. Renal potassium losses are associated with increased mineralocorticoid-receptor stimulation such as occurs with primary hyperreninism and primary aldosteronism.

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Option A: Diuretic therapy may lead to the loss of other electrolytes such as sodium, but the loss of potassium in association with digoxin therapy is most important. Increased delivery of sodium and/or non-absorbable ions (diuretic therapy, magnesium deficiency, genetic syndromes) to the distal nephron can also result in renal potassium wasting. GI losses are a common cause of hypokalemia with severe or chronic diarrhea being the most common extrarenal cause of hypokalemia.

Option B: Hypomagnesemia generally is associated with poor nutrition, alcoholism, and excessive GI or renal losses, not diuretic therapy. Magnesium homeostasis involves the kidney (primarily through the proximal tubule, the thick ascending loop of Henle, and the distal tubule), small bowel (primarily through the jejunum and ileum), and bone. Hypomagnesemia occurs when something, whether a drug or a disease condition, alters the homeostasis of magnesium.

Option D: Hypocalcemia is usually associated with inadequate vitamin D intake or synthesis, renal failure, or the use of drugs, such as aminoglycosides and corticosteroids. Calcitonin on the other hand lowers levels of calcium. Hypocalcemia is a common cause of tetany and neuromuscular irritability. An alkaline environment lowers calcium levels and induces tetany, whereas an acidic environment is protective.

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