Electrolyte homeostasis is fundamental to normal physiology, and imbalances can lead to life-threatening emergencies. As medication experts, pharmacists are critical in preventing, identifying, and managing electrolyte disorders, which are often caused or exacerbated by drug therapy. This quiz for PharmD students will test your knowledge of the pathophysiology, clinical presentation, and complex pharmacologic management of common and critical electrolyte abnormalities.
1. Which electrolyte is the primary determinant of plasma osmolality and is the most abundant cation in the extracellular fluid?
- Potassium
- Calcium
- Magnesium
- Sodium
Answer: Sodium
2. A patient with a serum sodium level of 122 mEq/L is diagnosed with hyponatremia. If this condition developed chronically, rapid correction carries a risk of:
- Cerebral edema
- Osmotic demyelination syndrome
- A hypertensive crisis
- Acute kidney injury
Answer: Osmotic demyelination syndrome
3. The treatment for a patient with hypovolemic hyponatremia primarily involves:
- Free water restriction.
- Administration of isotonic crystalloids (e.g., 0.9% NaCl).
- A vasopressin receptor antagonist like tolvaptan.
- A loop diuretic.
Answer: Administration of isotonic crystalloids (e.g., 0.9% NaCl).
4. A patient with a serum sodium of 160 mEq/L is diagnosed with hypernatremia. This condition represents a deficit of:
- Total body sodium.
- Total body potassium.
- Free water.
- Serum albumin.
Answer: Free water.
5. Which of the following is the most abundant intracellular cation, playing a critical role in the cardiac action potential and neuromuscular function?
- Sodium
- Potassium
- Calcium
- Chloride
Answer: Potassium
6. A patient with a serum potassium of 2.9 mEq/L has hypokalemia. A common cause of this is the use of which class of medication?
- ACE inhibitors
- Potassium-sparing diuretics
- Loop diuretics
- Beta-blockers
Answer: Loop diuretics
7. Peaked T waves on an electrocardiogram (ECG) are a classic sign of which electrolyte abnormality?
- Hypokalemia
- Hyperkalemia
- Hyponatremia
- Hypernatremia
Answer: Hyperkalemia
8. A patient has a serum potassium of 7.0 mEq/L with ECG changes. What is the first-line agent that should be administered immediately to stabilize the cardiac membrane?
- Intravenous insulin and dextrose
- Sodium polystyrene sulfonate
- Intravenous calcium gluconate
- Albuterol nebulization
Answer: Intravenous calcium gluconate
9. Intravenous insulin and dextrose are administered to treat hyperkalemia because this combination:
- Increases the renal excretion of potassium.
- Binds potassium in the gastrointestinal tract.
- Causes an intracellular shift, moving potassium from the blood into the cells.
- Directly antagonizes the effect of potassium on the heart.
Answer: Causes an intracellular shift, moving potassium from the blood into the cells.
10. A general rule for IV potassium repletion states that administering 10 mEq of KCl will typically raise the serum potassium by:
- 1.0 mEq/L
- 0.5 mEq/L
- 0.1 mEq/L
- 2.0 mEq/L
Answer: 0.1 mEq/L
11. The interpretation of a total serum calcium level can be inaccurate if the patient has low levels of which protein?
- Hemoglobin
- Myoglobin
- Albumin
- C-reactive protein
Answer: Albumin
12. A patient presents with perioral numbness, muscle cramping, and a positive Trousseau’s sign (carpopedal spasm). These are classic symptoms of:
- Hypercalcemia
- Hypocalcemia
- Hyperkalemia
- Hypokalemia
Answer: Hypocalcemia
13. A patient with severe, symptomatic hypercalcemia, often due to malignancy, is typically treated with:
- Oral calcium and vitamin D supplements.
- A thiazide diuretic.
- IV hydration with normal saline and a bisphosphonate like zoledronic acid.
- A potassium-sparing diuretic.
Answer: IV hydration with normal saline and a bisphosphonate like zoledronic acid.
14. Which of the following is a critical co-factor for potassium uptake and is essential for the function of the Na+/K+-ATPase pump?
- Sodium
- Chloride
- Phosphate
- Magnesium
Answer: Magnesium
15. A patient has refractory hypokalemia that is not correcting despite aggressive potassium replacement. The pharmacist should recommend checking the level of which other electrolyte?
- Sodium
- Chloride
- Bicarbonate
- Magnesium
Answer: Magnesium
16. Torsades de pointes is a life-threatening ventricular arrhythmia strongly associated with:
- Hypomagnesemia and a prolonged QT interval.
- Hypermagnesemia.
- Hyperphosphatemia.
- Hypophosphatemia.
Answer: Hypomagnesemia and a prolonged QT interval.
17. The treatment of choice for a patient with Torsades de pointes is:
- Intravenous calcium chloride.
- Intravenous magnesium sulfate.
- Intravenous sodium bicarbonate.
- Intravenous potassium phosphate.
Answer: Intravenous magnesium sulfate.
18. A patient with chronic kidney disease is at high risk for which electrolyte abnormality due to decreased excretion?
- Hypophosphatemia
- Hyperphosphatemia
- Hypokalemia
- Hyponatremia
Answer: Hyperphosphatemia
19. In the inpatient setting, hyperphosphatemia is often treated with:
- Oral phosphate supplements.
- Intravenous phosphate.
- Phosphate binders, such as sevelamer or calcium acetate.
- A high-phosphorus diet.
Answer: Phosphate binders, such as sevelamer or calcium acetate.
20. Refeeding syndrome, which can occur when a severely malnourished patient begins to receive nutrition, is characterized by a rapid and severe drop in which electrolyte?
- Sodium
- Chloride
- Calcium
- Phosphate
Answer: Phosphate
21. Which of the following medications is a common cause of drug-induced hyponatremia, especially in the elderly?
- Amlodipine
- Atorvastatin
- Furosemide
- A selective serotonin reuptake inhibitor (SSRI)
Answer: A selective serotonin reuptake inhibitor (SSRI)
22. Rapid IV push administration of potassium chloride is contraindicated because of the risk of:
- Severe pain at the infusion site.
- Fatal cardiac arrest.
- A hypertensive crisis.
- Anaphylaxis.
Answer: Fatal cardiac arrest.
23. Which class of antihypertensive drugs has a primary side effect of hyperkalemia?
- Calcium channel blockers
- Thiazide diuretics
- ACE inhibitors and ARBs
- Loop diuretics
Answer: ACE inhibitors and ARBs
24. The corrected calcium equation is used to:
- Estimate the physiologically active calcium level in patients with abnormal albumin levels.
- Calculate the dose of IV calcium needed.
- Determine the patient’s risk for kidney stones.
- Predict the patient’s response to bisphosphonate therapy.
Answer: Estimate the physiologically active calcium level in patients with abnormal albumin levels.
25. A pharmacist’s key role in managing electrolyte disorders includes:
- Recommending appropriate repletion or corrective therapies.
- Identifying drug-induced electrolyte imbalances.
- Counseling patients on dietary sources of electrolytes.
- All of the above.
Answer: All of the above.
26. A patient with diabetic ketoacidosis (DKA) presents with a normal or high serum potassium level, but their total body potassium is:
- Also high.
- Normal.
- Severely depleted.
- Not affected.
Answer: Severely depleted.
27. Why must potassium be repleted in a DKA patient before starting an insulin infusion if they are hypokalemic?
- Insulin will cause a further intracellular shift of potassium, worsening the hypokalemia.
- Insulin is inactivated by low potassium levels.
- Dextrose is required to activate the potassium.
- It is a hospital policy with no clinical reason.
Answer: Insulin will cause a further intracellular shift of potassium, worsening the hypokalemia.
28. A patient taking the potassium-sparing diuretic spironolactone should be counseled to avoid:
- High-sodium foods.
- Excessive intake of high-potassium foods or salt substitutes (potassium chloride).
- Dairy products.
- Grapefruit juice.
Answer: Excessive intake of high-potassium foods or salt substitutes (potassium chloride).
29. The pharmacist’s knowledge of __________ is critical for preparing safe and accurate intravenous electrolyte infusions.
- Marketing
- Sterile compounding and compatibility
- Pharmacy law
- Human resources
Answer: Sterile compounding and compatibility
30. Which of the following can cause hypomagnesemia?
- Chronic alcohol use.
- Diarrhea.
- Use of loop diuretics or PPIs.
- All of the above.
Answer: All of the above.
31. A patient with a critically low phosphate level (e.g., < 1 mg/dL) may experience which severe complication?
- Respiratory muscle weakness and heart failure.
- Hypertension.
- Seizures.
- A skin rash.
Answer: Respiratory muscle weakness and heart failure.
32. The maximum recommended infusion rate for peripheral IV potassium chloride is generally:
- 5 mEq/hour
- 10 mEq/hour
- 20 mEq/hour
- 40 mEq/hour
Answer: 10 mEq/hour
33. In a patient with hypervolemic hyponatremia (e.g., due to heart failure or cirrhosis), the treatment involves:
- Aggressive IV hydration with normal saline.
- Fluid and sodium restriction, often with a loop diuretic.
- A high-sodium diet.
- Administration of a colloid solution like albumin.
Answer: Fluid and sodium restriction, often with a loop diuretic.
34. The use of a “smart pump” drug library for electrolyte infusions is a safety technology designed to:
- Prevent dosing and infusion rate errors.
- Order the electrolyte from the pharmacy.
- Bill for the infusion.
- Document the administration of the dose.
Answer: Prevent dosing and infusion rate errors.
35. A patient receiving Total Parenteral Nutrition (TPN) requires careful daily monitoring and adjustment of:
- Their oral diet.
- Their electrolyte levels.
- Their exercise regimen.
- Their insurance plan.
Answer: Their electrolyte levels.
36. Thiazide diuretics can cause which of the following electrolyte imbalances?
- Hypokalemia, hyponatremia, and hypercalcemia.
- Hyperkalemia, hypernatremia, and hypocalcemia.
- Hypomagnesemia only.
- Hyperphosphatemia only.
Answer: Hypokalemia, hyponatremia, and hypercalcemia.
37. Which of the following is an oral agent used to treat chronic hyperkalemia?
- Patiromer or sodium zirconium cyclosilicate
- Spironolactone
- Lisinopril
- Losartan
Answer: Patiromer or sodium zirconium cyclosilicate
38. The pharmacist’s role in the ICU is critical for electrolyte management because:
- These patients often have fluctuating organ function and fluid status, requiring frequent dose adjustments.
- ICU patients rarely have electrolyte abnormalities.
- Nurses are responsible for all electrolyte management.
- Doses are the same for all ICU patients.
Answer: These patients often have fluctuating organ function and fluid status, requiring frequent dose adjustments.
39. When repleting IV phosphate, it is important to monitor which other electrolyte that can be reciprocally lowered?
- Sodium
- Potassium
- Chloride
- Calcium
Answer: Calcium
40. A patient’s acid-base status can affect electrolyte levels. For example, acidosis tends to cause potassium to move:
- Out of the cells, potentially causing hyperkalemia.
- Into the cells, potentially causing hypokalemia.
- There is no effect.
- Both into and out of the cells equally.
Answer: Out of the cells, potentially causing hyperkalemia.
41. The initial management of a patient with a traumatic brain injury may involve the therapeutic use of which electrolyte solution to reduce intracranial pressure?
- Hypotonic saline
- Hypertonic saline
- Potassium chloride
- Magnesium sulfate
Answer: Hypertonic saline
42. A key leadership role for a critical care pharmacist is to:
- Develop institutional protocols for electrolyte replacement.
- Manage the nursing schedule.
- Perform all blood draws for lab tests.
- Only dispense medications from the central pharmacy.
Answer: Develop institutional protocols for electrolyte replacement.
43. A pharmacist reviewing a patient’s home medication list during a “brown bag” review is a key step in identifying potential causes of:
- Chronic electrolyte disorders.
- Acute traumatic injuries.
- Hospital-acquired infections.
- The need for surgery.
Answer: Chronic electrolyte disorders.
44. A patient taking digoxin is more susceptible to toxicity if they develop:
- Hypokalemia or hypomagnesemia.
- Hyperkalemia.
- Hypercalcemia.
- Both A and C.
Answer: Both A and C.
45. Forging ahead in pharmacy practice means using __________ to proactively identify patients at risk for electrolyte abnormalities.
- A pharmacist’s intuition only.
- Analytics and reporting systems to screen EHR data.
- The pharmacy’s daily sales reports.
- A patient’s physical appearance.
Answer: Analytics and reporting systems to screen EHR data.
46. A patient with severe hypermagnesemia may present with:
- Agitation and tremor.
- Hypertension and tachycardia.
- Loss of deep tendon reflexes, hypotension, and respiratory depression.
- Seizures.
Answer: Loss of deep tendon reflexes, hypotension, and respiratory depression.
47. The antidote for severe, symptomatic hypermagnesemia is:
- IV magnesium sulfate.
- IV potassium chloride.
- IV calcium gluconate.
- IV sodium bicarbonate.
Answer: IV calcium gluconate.
48. Why is it important for a pharmacist to understand the electrolyte content of various IV fluids and admixtures?
- To ensure the patient does not receive an excessive electrolyte load, especially in renal impairment.
- It is only important for billing purposes.
- To be able to recommend the most expensive option.
- It is not an important consideration.
Answer: To ensure the patient does not receive an excessive electrolyte load, especially in renal impairment.
49. An effective interprofessional team approach to managing a patient with complex electrolyte disorders involves:
- The physician making all decisions without input.
- Each profession working in a silo.
- Collaborative communication between the pharmacist, physician, and nurse.
- The pharmacist only communicating with the lab.
Answer: Collaborative communication between the pharmacist, physician, and nurse.
50. The ultimate goal of electrolyte management is to:
- Achieve a perfect number on a lab report.
- Restore normal physiological function and prevent complications from the imbalance.
- Use as many IV drips as possible.
- Discharge the patient from the hospital quickly.
Answer: Restore normal physiological function and prevent complications from the imbalance.
I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.
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