Medical-Surgical Nursing: Fluids and Electrolytes Practice Questions
Test yourself on Fluids and Electrolytes with 12 original NCLEX-RN practice questions. Pick an answer to see instant feedback and a full explanation.
Free original practice questions for study purposes. Open Exam Prep is an independent study resource and is not affiliated with, endorsed by, or sponsored by the makers of NCLEX-RN.
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1. A client has vomiting and diarrhea for 24 hours. Which assessment finding is the highest priority for the nurse to report?
Explanation. Hypotension with a weak, rapid pulse suggests significant fluid volume deficit and possible shock, making it the priority. Thirst and dry mucous membranes can occur with dehydration, but unstable circulation is more urgent.
2. The nurse is reviewing laboratory results for a client taking furosemide. Which value requires the most immediate follow-up?
Explanation. Loop diuretics can cause potassium loss. A potassium level of 2.9 mEq/L is low and can increase the risk for dysrhythmias and muscle weakness. The other listed values are within typical adult reference ranges.
3. A client with hyperkalemia has peaked T waves on the cardiac monitor. Which provider prescription should the nurse anticipate first?
Explanation. With ECG changes from hyperkalemia, IV calcium gluconate is used first to stabilize the cardiac membrane. It does not remove potassium, so additional therapies may follow, but cardiac protection is the immediate priority.
4. A client with heart failure has gained 5 lb in 3 days and has crackles in both lung bases. Which interpretation is most appropriate?
Explanation. Rapid weight gain and lung crackles are classic signs of fluid volume excess, especially in heart failure. Daily weights are sensitive indicators of fluid status because 1 liter of retained fluid weighs about 2.2 lb.
5. A client has a serum sodium level of 124 mEq/L. Which assessment finding is most concerning?
Explanation. Severe hyponatremia can cause neurologic changes because water shifts into brain cells. New confusion, headache, seizures, or decreased level of consciousness require prompt attention.
6. The nurse is caring for a client with suspected hypernatremia. Which history finding best supports this concern?
Explanation. Hypernatremia often reflects water deficit more than excess sodium intake. Limited access to water, fever, heat exposure, or impaired thirst can lead to dehydration and elevated serum sodium.
7. Which clinical manifestation is most consistent with hypocalcemia?
Explanation. Hypocalcemia increases neuromuscular excitability and can cause perioral tingling, muscle cramps, tetany, positive Chvostek sign, or seizures. The other findings do not specifically indicate low calcium.
8. A client with hypercalcemia is prescribed IV normal saline. What is the main reason for this therapy?
Explanation. Hypercalcemia can cause dehydration and reduced kidney perfusion. Isotonic fluids expand volume and support urinary calcium excretion. Other medications may also be used depending on the cause and severity.
9. The nurse is monitoring a client with low magnesium. Which finding is most important to report?
Explanation. Magnesium helps regulate cardiac conduction and neuromuscular function. Hypomagnesemia can cause serious dysrhythmias, tremors, and seizures, so a ventricular rhythm change is the priority.
10. A client is receiving IV fluids for dehydration. Which finding best indicates that therapy is improving fluid volume status?
Explanation. Adequate urine output with improving blood pressure suggests better renal perfusion and intravascular volume. Worsening hypotension, oliguria, or respiratory crackles require reassessment and follow-up.
11. The nurse is teaching a client prescribed spironolactone. Which food choice should the nurse advise the client to discuss with the provider or dietitian?
Explanation. Spironolactone is potassium-sparing, so potassium-containing salt substitutes can raise potassium and increase hyperkalemia risk. The client should follow the prescribed diet and clarify potassium limits with the care team.
12. A client has syndrome of inappropriate antidiuretic hormone secretion (SIADH). Which order should the nurse expect?
Explanation. SIADH causes water retention and dilutional hyponatremia. Fluid restriction is commonly used to reduce free water intake. Severe symptomatic cases may require additional therapies, but unlimited water or hypotonic fluids would worsen dilution.
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FAQ
What fluid and electrolyte topics are highest yield for NCLEX?
Prioritize signs of fluid volume deficit and excess, potassium emergencies, sodium-related neurologic changes, calcium neuromuscular findings, magnesium-related rhythm risk, and common medication links such as loop diuretics and potassium-sparing diuretics.
How should I answer priority questions about electrolytes?
Look first for circulation, airway, neurologic status, and cardiac rhythm clues. Hypotension, ECG changes with potassium abnormalities, seizures, confusion from sodium shifts, and dysrhythmias from magnesium changes usually outrank stable teaching needs.
Which lab patterns should I memorize?
For NCLEX-style practice, know potassium around 3.5 to 5.0 mEq/L, sodium around 135 to 145 mEq/L, calcium around 8.5 to 10.5 mg/dL, and magnesium around 1.7 to 2.2 mg/dL, while also recognizing that clinical symptoms drive priority.