NCLEX Fluid and Electrolyte Balance 1 — Questions and Answers
Question 1: A patient has a serum sodium level of 125 mEq/L. Which condition does this value indicate?
- Hypernatremia
- Hyponatremia (Correct answer)
- Hyperkalemia
- Hypokalemia
Correct answer: Hyponatremia
A serum sodium below 135 mEq/L indicates hyponatremia; normal range is 135–145 mEq/L.
Question 2: Which electrolyte is the primary regulator of extracellular fluid osmolarity?
- Potassium
- Calcium
- Sodium (Correct answer)
- Magnesium
Correct answer: Sodium
Sodium is the dominant cation in extracellular fluid and the main determinant of extracellular osmolarity.
Question 3: A patient receiving furosemide (Lasix) is at greatest risk for which electrolyte imbalance?
- Hypernatremia
- Hypercalcemia
- Hypokalemia (Correct answer)
- Hypermagnesemia
Correct answer: Hypokalemia
Loop diuretics such as furosemide cause significant potassium wasting through the renal tubules.
Question 4: What is the normal serum potassium range?
- 2.5–3.5 mEq/L
- 3.5–5.0 mEq/L (Correct answer)
- 5.0–6.5 mEq/L
- 1.5–2.5 mEq/L
Correct answer: 3.5–5.0 mEq/L
Normal serum potassium is 3.5–5.0 mEq/L; values outside this range cause cardiac and neuromuscular complications.
Question 5: Which clinical finding is most characteristic of fluid volume deficit (dehydration)?
- Bounding pulse
- Increased urine output
- Poor skin turgor (Correct answer)
- Bradycardia
Correct answer: Poor skin turgor
Poor skin turgor (tenting) is a classic sign of dehydration caused by loss of interstitial fluid.
Question 6: A patient with hyperkalemia would most likely display which ECG change?
- Prolonged PR interval only
- Peaked T waves (Correct answer)
- Prominent U waves
- ST-segment depression
Correct answer: Peaked T waves
Peaked (tall, narrow) T waves are the earliest and most characteristic ECG finding in hyperkalemia.
Question 7: Which condition is most likely to cause hypocalcemia?
- Hyperparathyroidism
- Milk-alkali syndrome
- Hypoparathyroidism (Correct answer)
- Prolonged immobility
Correct answer: Hypoparathyroidism
Hypoparathyroidism reduces PTH secretion, decreasing calcium reabsorption from bone and kidney and causing hypocalcemia.
NCLEX Fluid and Electrolyte Balance 1
A patient has a serum sodium level of 125 mEq/L.
Which condition does this value indicate?