Nursing BS 231 Pathophysiology Exam 7 | Portage Learning | 2026/2027
Nursing BS 231 Pathophysiology Exam 7
Portage Learning | 2026/2027 Academic Year | 100% Correct Answers | Verified Update
Section 1: Fluid and Electrolyte Imbalances (Q1-Q12)
Q1: A 68-year-old patient with heart failure presents with weight gain of 4 kg over 3 days, jugular venous
distension, bilateral pitting edema, and crackles on auscultation. The nurse identifies these findings as
consistent with which fluid imbalance?
A. Hypervolemia [CORRECT]
B. Hypovolemia
C. Third-spacing
D. Isotonic dehydration
Correct Answer: A
Rationale: Hypervolemia is characterized by excessive fluid retention in the intravascular and interstitial compartments,
leading to weight gain, JVD, pitting edema, and pulmonary crackles from fluid accumulation in the lungs. This patient has
classic signs of fluid overload secondary to heart failure. Hypovolemia would present with weight loss, flat neck veins, and
dry mucous membranes. Third-spacing involves fluid shifting into the interstitial or transcellular space, not the intravascular
compartment. Isotonic dehydration involves proportional loss of water and sodium, which presents differently.
Q2: A nurse is caring for a patient with severe vomiting and diarrhea for the past 48 hours. The patient
has dry mucous membranes, decreased skin turgor, orthostatic hypotension, and a weak, thready pulse.
Which intravenous fluid is the priority initial intervention for this patient?
A. 0.9% sodium chloride (normal saline) [CORRECT]
B. Dextrose 5% in water (D5W)
C. 0.45% sodium chloride (half-normal saline)
D. Lactated Ringer solution
Correct Answer: A
Rationale: This patient demonstrates hypovolemia from significant gastrointestinal fluid losses. The priority intervention is
rapid volume expansion with an isotonic crystalloid solution. 0.9% sodium chloride is isotonic and remains in the
intravascular space, effectively restoring circulating volume. D5W is hypotonic and distributes throughout total body water,
making it ineffective for acute volume replacement. Half-normal saline is hypotonic and would not remain in the
intravascular compartment. While Lactated Ringer can also be used, 0.9% sodium chloride is the standard initial choice for
hypovolemic patients without specific electrolyte abnormalities.
Q3: A 55-year-old patient with chronic kidney disease has a serum sodium level of 152 mEq/L. The
patient is confused and thirsty. Which pathophysiological mechanism best explains why this patient is at
risk for hypernatremia?
A. Impaired renal concentrating ability and decreased thirst response [CORRECT]
B. Excessive aldosterone secretion causing sodium retention
C. Increased ADH secretion leading to water retention
D. Syndrome of inappropriate antidiuretic hormone (SIADH)
Correct Answer: A
Rationale: In chronic kidney disease, the kidneys lose their ability to concentrate urine and conserve water effectively. This
impairs the renal mechanism for maintaining sodium balance. Additionally, aging and certain neurological conditions can
Verified Update | 100% Correct Answers Page 1
, Nursing BS 231 Pathophysiology Exam 7 | Portage Learning | 2026/2027
diminish the thirst response, reducing compensatory water intake. While excessive aldosterone (Conn syndrome) causes
sodium retention, this patient has CKD as the primary issue, not primary adrenal dysfunction. Increased ADH and SIADH
both cause water retention leading to hyponatremia, not hypernatremia. The combination of impaired renal water
conservation and inadequate fluid intake creates the hypernatremic state.
Q4: A postoperative patient who has been receiving 0.45% sodium chloride at 125 mL/hr for 36 hours
develops a headache, confusion, nausea, and muscle weakness. Serum sodium is 125 mEq/L. Which
nursing intervention is the highest priority?
A. Slowly infuse 3% hypertonic saline as prescribed [CORRECT]
B. Administer furosemide (Lasix) intravenously
C. Restrict free water and increase sodium intake orally
D. Discontinue IV fluids and administer D5W
Correct Answer: A
Rationale: This patient has developed symptomatic hyponatremia (Na 125 mEq/L with neurological symptoms), which is a
medical emergency. The highest priority is to carefully raise the serum sodium with hypertonic saline (3% NaCl) to prevent
cerebral edema and herniation. The correction must be slow (no more than 8-10 mEq/L in 24 hours) to avoid osmotic
demyelination syndrome (central pontine myelinolysis). Furosemide is used for hypervolemic hyponatremia, not this scenario.
Simple fluid restriction is appropriate for mild asymptomatic hyponatremia. Administering D5W would further dilute serum
sodium and worsen the condition.
Q5: A patient with end-stage renal disease missed a dialysis session and now has muscle weakness,
peaked T waves on ECG, and serum potassium of 7.2 mEq/L. Which of the following is the most critical
first intervention?
A. Administer intravenous calcium gluconate [CORRECT]
B. Administer regular insulin with D50 intravenously
C. Administer sodium polystyrene sulfonate (Kayexalate) orally
D. Prepare the patient for emergency hemodialysis
Correct Answer: A
Rationale: In severe hyperkalemia (K 7.2 mEq/L) with ECG changes (peaked T waves), the most critical first intervention is
IV calcium gluconate, which stabilizes cardiac cell membranes and prevents life-threatening arrhythmias. Calcium does not
lower the potassium level but buys time by protecting the heart. Insulin with D50 shifts potassium intracellularly and is the
second step. Kayexalate is a slow-acting exchange resin that takes hours to work. Emergency hemodialysis is definitive but
takes time to initiate. The ABC (Airway, Breathing, Circulation) priority makes cardiac membrane stabilization the first
action before lowering potassium.
Q6: A patient with a serum calcium level of 6.8 mg/dL presents with tetany, positive Trousseau and
Chvostek signs, and laryngospasm. Which underlying pathophysiological mechanism is most likely
responsible for these clinical manifestations?
A. Decreased excitability threshold of nerve and muscle cells due to low extracellular calcium
[CORRECT]
B. Increased parathyroid hormone secretion causing bone resorption
C. Excessive vitamin D activation leading to gastrointestinal calcium absorption
D. Elevated serum phosphate directly depressing neuronal function
Correct Answer: A
Rationale: Hypocalcemia (Ca 6.8 mg/dL, normal 8.5-10.5 mg/dL) lowers the excitability threshold of nerve and muscle cell
membranes, causing spontaneous depolarization and hyperexcitability. This manifests as tetany, positive Trousseau sign
(carpal spasm after blood pressure cuff inflation), positive Chvostek sign (facial muscle twitch on facial nerve tap), and
potentially life-threatening laryngospasm. Increased PTH would be a compensatory response to hypocalcemia, not the cause.
Excessive vitamin D causes hypercalcemia, not hypocalcemia. While elevated phosphate can contribute to hypocalcemia by
Verified Update | 100% Correct Answers Page 2
Nursing BS 231 Pathophysiology Exam 7
Portage Learning | 2026/2027 Academic Year | 100% Correct Answers | Verified Update
Section 1: Fluid and Electrolyte Imbalances (Q1-Q12)
Q1: A 68-year-old patient with heart failure presents with weight gain of 4 kg over 3 days, jugular venous
distension, bilateral pitting edema, and crackles on auscultation. The nurse identifies these findings as
consistent with which fluid imbalance?
A. Hypervolemia [CORRECT]
B. Hypovolemia
C. Third-spacing
D. Isotonic dehydration
Correct Answer: A
Rationale: Hypervolemia is characterized by excessive fluid retention in the intravascular and interstitial compartments,
leading to weight gain, JVD, pitting edema, and pulmonary crackles from fluid accumulation in the lungs. This patient has
classic signs of fluid overload secondary to heart failure. Hypovolemia would present with weight loss, flat neck veins, and
dry mucous membranes. Third-spacing involves fluid shifting into the interstitial or transcellular space, not the intravascular
compartment. Isotonic dehydration involves proportional loss of water and sodium, which presents differently.
Q2: A nurse is caring for a patient with severe vomiting and diarrhea for the past 48 hours. The patient
has dry mucous membranes, decreased skin turgor, orthostatic hypotension, and a weak, thready pulse.
Which intravenous fluid is the priority initial intervention for this patient?
A. 0.9% sodium chloride (normal saline) [CORRECT]
B. Dextrose 5% in water (D5W)
C. 0.45% sodium chloride (half-normal saline)
D. Lactated Ringer solution
Correct Answer: A
Rationale: This patient demonstrates hypovolemia from significant gastrointestinal fluid losses. The priority intervention is
rapid volume expansion with an isotonic crystalloid solution. 0.9% sodium chloride is isotonic and remains in the
intravascular space, effectively restoring circulating volume. D5W is hypotonic and distributes throughout total body water,
making it ineffective for acute volume replacement. Half-normal saline is hypotonic and would not remain in the
intravascular compartment. While Lactated Ringer can also be used, 0.9% sodium chloride is the standard initial choice for
hypovolemic patients without specific electrolyte abnormalities.
Q3: A 55-year-old patient with chronic kidney disease has a serum sodium level of 152 mEq/L. The
patient is confused and thirsty. Which pathophysiological mechanism best explains why this patient is at
risk for hypernatremia?
A. Impaired renal concentrating ability and decreased thirst response [CORRECT]
B. Excessive aldosterone secretion causing sodium retention
C. Increased ADH secretion leading to water retention
D. Syndrome of inappropriate antidiuretic hormone (SIADH)
Correct Answer: A
Rationale: In chronic kidney disease, the kidneys lose their ability to concentrate urine and conserve water effectively. This
impairs the renal mechanism for maintaining sodium balance. Additionally, aging and certain neurological conditions can
Verified Update | 100% Correct Answers Page 1
, Nursing BS 231 Pathophysiology Exam 7 | Portage Learning | 2026/2027
diminish the thirst response, reducing compensatory water intake. While excessive aldosterone (Conn syndrome) causes
sodium retention, this patient has CKD as the primary issue, not primary adrenal dysfunction. Increased ADH and SIADH
both cause water retention leading to hyponatremia, not hypernatremia. The combination of impaired renal water
conservation and inadequate fluid intake creates the hypernatremic state.
Q4: A postoperative patient who has been receiving 0.45% sodium chloride at 125 mL/hr for 36 hours
develops a headache, confusion, nausea, and muscle weakness. Serum sodium is 125 mEq/L. Which
nursing intervention is the highest priority?
A. Slowly infuse 3% hypertonic saline as prescribed [CORRECT]
B. Administer furosemide (Lasix) intravenously
C. Restrict free water and increase sodium intake orally
D. Discontinue IV fluids and administer D5W
Correct Answer: A
Rationale: This patient has developed symptomatic hyponatremia (Na 125 mEq/L with neurological symptoms), which is a
medical emergency. The highest priority is to carefully raise the serum sodium with hypertonic saline (3% NaCl) to prevent
cerebral edema and herniation. The correction must be slow (no more than 8-10 mEq/L in 24 hours) to avoid osmotic
demyelination syndrome (central pontine myelinolysis). Furosemide is used for hypervolemic hyponatremia, not this scenario.
Simple fluid restriction is appropriate for mild asymptomatic hyponatremia. Administering D5W would further dilute serum
sodium and worsen the condition.
Q5: A patient with end-stage renal disease missed a dialysis session and now has muscle weakness,
peaked T waves on ECG, and serum potassium of 7.2 mEq/L. Which of the following is the most critical
first intervention?
A. Administer intravenous calcium gluconate [CORRECT]
B. Administer regular insulin with D50 intravenously
C. Administer sodium polystyrene sulfonate (Kayexalate) orally
D. Prepare the patient for emergency hemodialysis
Correct Answer: A
Rationale: In severe hyperkalemia (K 7.2 mEq/L) with ECG changes (peaked T waves), the most critical first intervention is
IV calcium gluconate, which stabilizes cardiac cell membranes and prevents life-threatening arrhythmias. Calcium does not
lower the potassium level but buys time by protecting the heart. Insulin with D50 shifts potassium intracellularly and is the
second step. Kayexalate is a slow-acting exchange resin that takes hours to work. Emergency hemodialysis is definitive but
takes time to initiate. The ABC (Airway, Breathing, Circulation) priority makes cardiac membrane stabilization the first
action before lowering potassium.
Q6: A patient with a serum calcium level of 6.8 mg/dL presents with tetany, positive Trousseau and
Chvostek signs, and laryngospasm. Which underlying pathophysiological mechanism is most likely
responsible for these clinical manifestations?
A. Decreased excitability threshold of nerve and muscle cells due to low extracellular calcium
[CORRECT]
B. Increased parathyroid hormone secretion causing bone resorption
C. Excessive vitamin D activation leading to gastrointestinal calcium absorption
D. Elevated serum phosphate directly depressing neuronal function
Correct Answer: A
Rationale: Hypocalcemia (Ca 6.8 mg/dL, normal 8.5-10.5 mg/dL) lowers the excitability threshold of nerve and muscle cell
membranes, causing spontaneous depolarization and hyperexcitability. This manifests as tetany, positive Trousseau sign
(carpal spasm after blood pressure cuff inflation), positive Chvostek sign (facial muscle twitch on facial nerve tap), and
potentially life-threatening laryngospasm. Increased PTH would be a compensatory response to hypocalcemia, not the cause.
Excessive vitamin D causes hypercalcemia, not hypocalcemia. While elevated phosphate can contribute to hypocalcemia by
Verified Update | 100% Correct Answers Page 2
