,1. A nursing student is reviewing the distribution of body fluids. Which statement accurately
describes the composition of the intracellular fluid (ICF) compartment?
A) High in sodium and chloride; low in potassium
B) High in potassium, magnesium, and phosphate; low in sodium and chloride
C) Equal concentrations of sodium and potassium
D) High in sodium and bicarbonate; low in protein
Correct Answer: High in potassium, magnesium, and phosphate; low in sodium and chloride
Rationale: The ICF is the fluid inside cells and is rich in potassium (K⁺), magnesium (Mg²⁺), and
phosphate. It is low in sodium (Na⁺) and chloride (Cl⁻), which are the primary electrolytes of the
extracellular fluid (ECF). The sodium-potassium pump maintains this concentration difference.
2. A nurse is caring for a patient with a serum sodium level of 118 mEq/L who is exhibiting
confusion and lethargy. What is the priority intervention?
A) Restrict oral fluids to 800 mL/day
B) Prepare to administer a 3% saline bolus
C) Administer IV normal saline at 150 mL/hr
D) Encourage oral intake of salty foods
Correct Answer: Prepare to administer a 3% saline bolus
Rationale: Severe hyponatremia (Na <120 mEq/L) with neurological symptoms is a medical
emergency due to the risk of cerebral edema. Hypertonic saline (3% NaCl) is required to rapidly
increase serum sodium and reduce brain swelling. Fluid restriction is appropriate for
asymptomatic hyponatremia, but not the priority here.
3. Which hormone is primarily responsible for sodium and water retention by the kidneys?
,A) Antidiuretic hormone (ADH)
B) Aldosterone
C) Atrial natriuretic peptide (ANP)
D) Brain natriuretic peptide (BNP)
Correct Answer: Aldosterone
Rationale: Aldosterone, released from the adrenal cortex, promotes sodium and water
reabsorption in the kidneys, increasing blood volume. ADH primarily regulates water
reabsorption alone, while ANP and BNP promote sodium and water excretion.
4. A patient has a serum potassium level of 6.8 mEq/L and ECG changes. Which intervention
should the nurse perform first to stabilize the cardiac membrane?
A) Administer sodium polystyrene sulfonate (Kayexalate)
B) Give IV calcium gluconate
C) Start insulin with dextrose IV
D) Administer IV furosemide
Correct Answer: Give IV calcium gluconate
Rationale: Calcium gluconate is given first to immediately stabilize the cardiac cell membrane
and prevent life-threatening dysrhythmias in hyperkalemia. Other interventions like
insulin/glucose shift potassium into cells, and Kayexalate removes it, but they take longer to act.
5. A patient who is post-thyroidectomy has a serum calcium of 6.5 mg/dL. Which finding would
require immediate intervention?
A) Nausea and vomiting
B) Positive Trousseau's sign
, C) Stridor and laryngospasm
D) Hypoactive bowel sounds
Correct Answer: Stridor and laryngospasm
Rationale: Stridor and laryngospasm indicate severe airway compromise due to hypocalcemia-
induced tetany. This is a life-threatening emergency requiring immediate IV calcium
administration. Trousseau's sign is a classic sign of hypocalcemia but is not immediately life-
threatening.
6. An older adult patient is at higher risk for dehydration. Which physiological change
contributes to this increased risk?
A) Increased total body water percentage
B) Decreased thirst sensation and decreased GFR
C) Increased glomerular filtration rate (GFR)
D) Enhanced renal concentrating ability
Correct Answer: Decreased thirst sensation and decreased glomerular filtration rate (GFR)
Rationale: Older adults have a decreased total body water, blunted thirst response, and
decreased GFR, all of which increase the risk of fluid volume deficits. These age-related changes
make older adults particularly vulnerable to dehydration.
7. Which electrolyte imbalance is a hallmark of refeeding syndrome?
A) Hyperphosphatemia
B) Hypophosphatemia
C) Hyperkalemia
D) Hypermagnesemia
describes the composition of the intracellular fluid (ICF) compartment?
A) High in sodium and chloride; low in potassium
B) High in potassium, magnesium, and phosphate; low in sodium and chloride
C) Equal concentrations of sodium and potassium
D) High in sodium and bicarbonate; low in protein
Correct Answer: High in potassium, magnesium, and phosphate; low in sodium and chloride
Rationale: The ICF is the fluid inside cells and is rich in potassium (K⁺), magnesium (Mg²⁺), and
phosphate. It is low in sodium (Na⁺) and chloride (Cl⁻), which are the primary electrolytes of the
extracellular fluid (ECF). The sodium-potassium pump maintains this concentration difference.
2. A nurse is caring for a patient with a serum sodium level of 118 mEq/L who is exhibiting
confusion and lethargy. What is the priority intervention?
A) Restrict oral fluids to 800 mL/day
B) Prepare to administer a 3% saline bolus
C) Administer IV normal saline at 150 mL/hr
D) Encourage oral intake of salty foods
Correct Answer: Prepare to administer a 3% saline bolus
Rationale: Severe hyponatremia (Na <120 mEq/L) with neurological symptoms is a medical
emergency due to the risk of cerebral edema. Hypertonic saline (3% NaCl) is required to rapidly
increase serum sodium and reduce brain swelling. Fluid restriction is appropriate for
asymptomatic hyponatremia, but not the priority here.
3. Which hormone is primarily responsible for sodium and water retention by the kidneys?
,A) Antidiuretic hormone (ADH)
B) Aldosterone
C) Atrial natriuretic peptide (ANP)
D) Brain natriuretic peptide (BNP)
Correct Answer: Aldosterone
Rationale: Aldosterone, released from the adrenal cortex, promotes sodium and water
reabsorption in the kidneys, increasing blood volume. ADH primarily regulates water
reabsorption alone, while ANP and BNP promote sodium and water excretion.
4. A patient has a serum potassium level of 6.8 mEq/L and ECG changes. Which intervention
should the nurse perform first to stabilize the cardiac membrane?
A) Administer sodium polystyrene sulfonate (Kayexalate)
B) Give IV calcium gluconate
C) Start insulin with dextrose IV
D) Administer IV furosemide
Correct Answer: Give IV calcium gluconate
Rationale: Calcium gluconate is given first to immediately stabilize the cardiac cell membrane
and prevent life-threatening dysrhythmias in hyperkalemia. Other interventions like
insulin/glucose shift potassium into cells, and Kayexalate removes it, but they take longer to act.
5. A patient who is post-thyroidectomy has a serum calcium of 6.5 mg/dL. Which finding would
require immediate intervention?
A) Nausea and vomiting
B) Positive Trousseau's sign
, C) Stridor and laryngospasm
D) Hypoactive bowel sounds
Correct Answer: Stridor and laryngospasm
Rationale: Stridor and laryngospasm indicate severe airway compromise due to hypocalcemia-
induced tetany. This is a life-threatening emergency requiring immediate IV calcium
administration. Trousseau's sign is a classic sign of hypocalcemia but is not immediately life-
threatening.
6. An older adult patient is at higher risk for dehydration. Which physiological change
contributes to this increased risk?
A) Increased total body water percentage
B) Decreased thirst sensation and decreased GFR
C) Increased glomerular filtration rate (GFR)
D) Enhanced renal concentrating ability
Correct Answer: Decreased thirst sensation and decreased glomerular filtration rate (GFR)
Rationale: Older adults have a decreased total body water, blunted thirst response, and
decreased GFR, all of which increase the risk of fluid volume deficits. These age-related changes
make older adults particularly vulnerable to dehydration.
7. Which electrolyte imbalance is a hallmark of refeeding syndrome?
A) Hyperphosphatemia
B) Hypophosphatemia
C) Hyperkalemia
D) Hypermagnesemia
