Which electrolyte imbalance is associated with loop diuretic?

Appeared in: NORCET 3 - 2022 (Shift-2)

Explanation

Loop diuretics (e.g., furosemide, bumetanide) act on the thick ascending limb of the loop of Henle.
They inhibit the Na-K-2Cl cotransporter, which prevents the reabsorption of these electrolytes.
This action leads to increased urinary excretion of sodium, chloride, and, most notably, potassium.
The significant loss of potassium in the urine results in hypokalemia, a serum potassium level below 3.5 mEq/L.

Option A: Hyperkalemia (high potassium) is the opposite effect of what loop diuretics cause.
Option C: Hypernatremia (high sodium) is not a typical side effect. Loop diuretics waste sodium, which can lead to hyponatremia (low sodium).
Option D: Hypervolemia means fluid volume excess. Loop diuretics are prescribed specifically to treat hypervolemia by removing excess fluid from the body.

Visual 1: Diagram: A diagram of the nephron highlighting the thick ascending limb of the loop of Henle to show the site of action for loop diuretics.
Visual 2: ECG Strip: An image comparing a normal ECG with one showing the characteristic changes of hypokalemia (flattened T-waves, prominent U-waves, and ST depression).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Electrolyte imbalances caused by loop diuretics as background academic context rather than a clinical decision trigger.
Nurses must closely monitor serum potassium levels in patients receiving loop diuretics, especially in high doses or with long-term therapy.
Patient education is crucial. Patients should be taught to recognize symptoms of hypokalemia (muscle weakness, cramping, palpitations) and to report them immediately.
Dietary counseling is important; encouraging intake of potassium-rich foods like bananas, oranges, potatoes, and spinach can help counteract potassium loss.

How to Approach the Question

First, identify the drug class mentioned in the question: 'loop diuretic'.
Recall the primary mechanism of action for this drug class. Loop diuretics block the Na-K-2Cl cotransporter in the loop of Henle.
Think through the consequences of this mechanism. Blocking this transporter leads to the excretion of sodium, chloride, and potassium.
Connect the increased excretion of potassium to the potential electrolyte imbalances listed in the options.
Increased potassium loss directly leads to 'hypokalemia' (low potassium).
Evaluate the other options to confirm they are incorrect. Hyperkalemia is the opposite effect. Hypernatremia is unlikely as sodium is wasted. Hypervolemia is a condition treated by, not caused by, these diuretics.

Concept Tested & Keywords

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Practise the full NORCET 3 - 2022 (Shift-2)

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