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Urinary System

Electrolyte Imbalance in Renal Disease Practice Questions

20 free Electrolyte Imbalance in Renal Disease practice questions for the NCLEX Exam. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.

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Question 1 of 20 Medium

What is the most likely mechanism behind hyperkalemia in a patient with advanced chronic kidney disease (CKD)?

  1. A Diuretics drive the kidneys to excrete excess potassium
  2. B Reduced glomerular filtration limits potassium excretion
  3. C Excessive dietary sodium intake drives potassium retention
  4. D Potassium shifts intracellularly, raising the serum level

Correct answer: Reduced glomerular filtration limits potassium excretion

In CKD reduced glomerular filtration and tubular excretion of potassium lead to hyperkalemia.

Question 2 of 20 Medium

What is the likely mechanism of hyperphosphatemia in a patient with acute renal failure?

  1. A Markedly increased renal excretion of phosphate
  2. B Reduced filtration and excretion by damaged kidneys
  3. C Excessive dietary phosphate intake acting alone
  4. D Increased conversion of vitamin D to its active form

Correct answer: Reduced filtration and excretion by damaged kidneys

With renal failure the kidneys cannot filter and excrete phosphate efficiently, leading to phosphate retention (hyperphosphatemia).

Question 3 of 20 Medium

Which electrolyte pair is characteristically abnormal in CKD mineral bone disorder (CKD-MBD)?

  1. A Hypercalcemia and hypophosphatemia
  2. B Hypocalcemia and hyperphosphatemia
  3. C Hypokalemia and hypomagnesemia
  4. D Hypernatremia and hypermagnesemia

Correct answer: Hypocalcemia and hyperphosphatemia

In CKD the impaired phosphate excretion causes hyperphosphatemia, and decreased conversion of vitamin D leads to hypocalcemia.

Question 4 of 20 Hard

What is the most urgent electrolyte-related risk in a dialysis patient with peaked T waves on ECG and high serum potassium levels?

  1. A Hypovolemia from fluid shifts
  2. B Cardiac arrhythmia due to hyperkalemia
  3. C Cerebral edema due to hypernatremia
  4. D Bone demineralization due to hypocalcemia

Correct answer: Cardiac arrhythmia due to hyperkalemia

Hyperkalemia is a life-threatening electrolyte disturbance in renal disease, risking fatal cardiac arrhythmias.

Question 5 of 20 Easy

What is a common contributing mechanism to the development of hyponatremia in a patient with CKD?

  1. A Excessive renal excretion of free water
  2. B Dilutional hyponatremia from fluid retention
  3. C Primary adrenal cortical hyperactivity
  4. D Excessive dietary sodium intake daily

Correct answer: Dilutional hyponatremia from fluid retention

Kidney dysfunction often leads to impaired ability to excrete free water, leading to dilutional hyponatremia.

Question 6 of 20 Medium

What is the correct statement regarding hypermagnesemia in a patient with CKD?

  1. A Renal magnesium excretion is increased in CKD
  2. B Decreased renal clearance accumulates magnesium
  3. C Hypermagnesemia drives increased PTH secretion
  4. D Hypermagnesemia is generally protective in CKD

Correct answer: Decreased renal clearance accumulates magnesium

In CKD, impaired renal excretion causes magnesium retention and hypermagnesemia.

Question 7 of 20 Medium

What would you expect in a patient with advanced CKD related to calcium metabolism?

  1. A Elevated 1,25-dihydroxyvitamin D and hypercalcemia
  2. B Normal vitamin D conversion and normocalcemia
  3. C Decreased 1,25-dihydroxyvitamin D production and hypocalcemia
  4. D Increased gastrointestinal calcium absorption despite kidney failure

Correct answer: Decreased 1,25-dihydroxyvitamin D production and hypocalcemia

Kidneys produce active vitamin D (1,25-OH₂D); in CKD this falls, reducing calcium absorption and causing hypocalcemia.

Question 8 of 20 Hard

Which electrolyte disturbance typically accompanies metabolic acidosis in a patient with acute tubular necrosis (ATN)?

  1. A Hypokalemia from urinary losses
  2. B Hypomagnesemia from poor intake
  3. C Hyperphosphatemia with disturbed calcium-phosphate balance
  4. D Hypernatremia from water depletion

Correct answer: Hyperphosphatemia with disturbed calcium-phosphate balance

With decreased renal excretion and acidosis, potassium shifts out of cells and renal clearance is reduced, producing hyperkalemia.

Question 9 of 20 Medium

Which electrolyte disturbance is most directly linked to vascular calcification in CKD?

  1. A Hypokalemia
  2. B Hypomagnesemia
  3. C Hyperphosphatemia and disturbed calcium-phosphate balance
  4. D Hypernatremia

Correct answer: Hyperphosphatemia and disturbed calcium-phosphate balance

High phosphate, low calcium, and disturbances in mineral metabolism contribute to vascular calcification and morbidity in CKD-MBD.

Question 10 of 20 Easy

What is the best interpretation of a serum phosphate level of 5.8 mg/dL in a patient on chronic dialysis?

  1. A Normal phosphate level for dialysis patients
  2. B Mild hypophosphatemia
  3. C Hyperphosphatemia requiring intervention
  4. D Phosphate level irrelevant in dialysis

Correct answer: Hyperphosphatemia requiring intervention

CKD patients, especially on dialysis, often retain phosphate and levels above ~4.5 mg/dL are considered elevated and merit treatment.

Question 11 of 20 Medium

In renal failure, how can hyponatremia be present despite normal dietary sodium intake?

  1. A Excess aldosterone driving renal sodium loss
  2. B Impaired water excretion diluting serum sodium
  3. C Increased renal sodium excretion via tubules
  4. D Primary adrenal cortical insufficiency

Correct answer: Impaired water excretion diluting serum sodium

Kidney failure often reduces free water excretion, causing dilutional hyponatremia even though sodium amount remains similar.

Question 12 of 20 Hard

What correctly describes potassium handling in CKD?

  1. A A higher GFR always protects against hyperkalemia
  2. B RAAS inhibitors reliably lower serum potassium in CKD
  3. C Declining GFR raises hyperkalemia risk via impaired excretion
  4. D Hypokalemia is more common than hyperkalemia in advanced CKD

Correct answer: Declining GFR raises hyperkalemia risk via impaired excretion

The kidneys are the main route of potassium excretion; as kidney function declines, potassium excretion falls and hyperkalemia becomes more likely.

Question 13 of 20 Medium

What is the underlying reason for a patient with CKD having low serum calcium and elevated PTH (secondary hyperparathyroidism)?

  1. A Excess active vitamin D produced by the kidneys
  2. B Phosphate retention with reduced vitamin D activation
  3. C Over-secretion of calcitonin from the thyroid
  4. D Increased gastrointestinal calcium absorption

Correct answer: Phosphate retention with reduced vitamin D activation

Retained phosphate binds calcium causing hypocalcemia and kidneys cannot activate vitamin D—leading to increased PTH (secondary hyperparathyroidism).

Question 14 of 20 Medium

Which electrolyte disturbance is least characteristic of renal failure?

  1. A Hyperkalemia from impaired potassium excretion
  2. B Hyperphosphatemia from phosphate retention
  3. C Hypocalcemia from low vitamin D activation
  4. D Isolated hypernatremia from increased urinary sodium loss

Correct answer: Isolated hypernatremia from increased urinary sodium loss

In renal failure sodium excretion is reduced (not increased); hypernatremia from increased urinary sodium loss is less common than the other listed imbalances.

Question 15 of 20 Easy

What effect can rising magnesium levels cause in renal failure?

  1. A Increased PTH secretion causing hypercalcemia
  2. B Suppression of PTH secretion causing hypocalcemia
  3. C Increased renal sodium and water retention
  4. D Enhanced urinary excretion of potassium

Correct answer: Suppression of PTH secretion causing hypocalcemia

Hypermagnesemia can suppress PTH secretion leading to hypocalcemia and related effects.

Question 16 of 20 Hard

Which electrolyte patterns are common in acute kidney injury (AKI)?

  1. A Hyperkalemia, hyperphosphatemia, and hypocalcemia
  2. B Hypokalemia, hypophosphatemia, hypernatremia
  3. C Hypercalcemia, hyponatremia, hypermagnesemia
  4. D Hypocalcemia, hypernatremia, hyperkalemia

Correct answer: Hyperkalemia, hyperphosphatemia, and hypocalcemia

AKI reduces excretion of K⁺ and phosphate leading to hyperkalemia and hyperphosphatemia; calcium drops due to phosphate retention and impaired activation of vitamin D.

Question 17 of 20 Medium

What likely electrolyte/metabolic abnormality underlies fatigue, bone pain, and elevated alkaline phosphatase in a patient with CKD?

  1. A Hypokalemia from urinary potassium wasting
  2. B Secondary hyperparathyroidism from hypocalcemia
  3. C Hypermagnesemia driving abnormal bone formation
  4. D Primary hyperaldosteronism with sodium retention

Correct answer: Secondary hyperparathyroidism from hypocalcemia

In CKD mineral bone disorder, hypocalcemia and hyperphosphatemia drive secondary hyperparathyroidism causing bone turnover and elevated bone markers.

Question 18 of 20 Easy

What dietary advice is most appropriate for a patient with CKD and elevated phosphate?

  1. A Increase dairy and meat intake without any restriction
  2. B Restrict high-phosphorus foods and use a phosphate binder
  3. C Ignore phosphate levels as they have no clinical significance
  4. D Increase dietary phosphate intake to stimulate PTH release

Correct answer: Restrict high-phosphorus foods and use a phosphate binder

In CKD where phosphate excretion is impaired, diet restriction plus binders help control hyperphosphatemia and complications.

Question 19 of 20 Medium

What should be the nursing teaching focus for a patient with CKD and high serum potassium on an ACE inhibitor?

  1. A Encourage high-potassium foods
  2. B Avoid potassium‐containing salt substitutes
  3. C No dietary modifications needed
  4. D Stop ACE inhibitor without consulting physician

Correct answer: Avoid potassium‐containing salt substitutes

ACE inhibitors reduce potassium excretion, raising the risk of hyperkalemia; salt substitutes often contain potassium and should be avoided.

Question 20 of 20 Hard

Why might a patient with CKD develop metabolic acidosis along with electrolyte imbalances?

  1. A The kidneys begin to over-excrete hydrogen ions into urine
  2. B Impaired renal acid excretion and bicarbonate regeneration
  3. C Excessive reabsorption of bicarbonate by the renal tubules
  4. D Increased secretion of metabolic acid by the lungs

Correct answer: Impaired renal acid excretion and bicarbonate regeneration

Kidneys failing to excrete hydrogen ions and regenerate bicarbonate leads to metabolic acidosis, which in turn affects electrolyte shifts (e.g., increasing potassium).

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