lOMoARcPSD|26582732
Electrolyte Imbalances Exam 1 practice questions
chapter 10 rationale part 2 electrolytes
Med surg (Jersey College Nursing School)
Question 1:
What is the primary determinant of extracellular fluid (ECF) volume?
Answer: Sodium (Na+).
Rationale:
Sodium is the most abundant electrolyte in the ECF and plays a critical role in determining ECF volume and osmolality.
Its high concentration and inability to easily cross the plasma membrane contribute to its influence on water
distribution.
Question 2:
What mechanisms regulate sodium levels in the body?
Answer: ADH, thirst, and the renin–angiotensin–aldosterone system.
Rationale:
These mechanisms work together to maintain sodium balance. ADH regulates water retention, thirst drives fluid intake,
and the renin–angiotensin–aldosterone system adjusts sodium reabsorption in the kidneys.
Question 3:
Why is sodium important in muscle contraction and nerve impulse transmission?
Answer: Sodium establishes the electrochemical state necessary for these processes.
Rationale:
Sodium ions play a key role in generating action potentials and maintaining membrane potential, which are essential for
muscle contraction and nerve signal transmission.
Question 4:
How does a loss or gain of sodium typically affect water balance in the body?
Answer: It is usually accompanied by a loss or gain of water. Rationale:
Sodium directly influences water movement due to its osmotic properties. Changes in sodium levels lead to shifts in
water distribution to maintain osmotic equilibrium.
Question 5:
What condition is associated with the oversecretion of antidiuretic hormone (ADH)? Answer:
Syndrome of inappropriate secretion of antidiuretic hormone (SIADH).
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Rationale:
SIADH occurs when excessive ADH is secreted, leading to water retention and dilutional hyponatremia. It is triggered by
factors like brain injury, malignancies, and certain medications.
Question 6:
Which patients are at risk for developing SIADH?
Answer: Older adults, patients with brain tumors or pulmonary malignancies, those on mechanical ventilation, and
individuals taking ssris.
Rationale:
These conditions or treatments can disrupt the regulation of ADH, leading to inappropriate secretion and subsequent
sodium imbalance.
Question 7:
What happens when circulating plasma osmolality decreases?
Answer: ADH is released from the posterior pituitary.
Rationale:
ADH secretion is triggered by a drop in plasma osmolality, blood volume, or blood pressure to conserve water and
restore balance.
Question 8:
How does SIADH affect sodium levels?
Answer: It causes hyponatremia due to water retention and dilution of sodium in the plasma.
Rationale:
The excess ADH promotes water reabsorption in the kidneys, diluting sodium and lowering its concentration in the ECF.
Question 9:
What are the two most common sodium imbalances?
Answer: Sodium deficit (hyponatremia) and sodium excess (hypernatremia).
Rationale:
These imbalances occur when sodium levels fall below or exceed the normal range of 135–145 meq/L, impacting fluid
balance and cellular function.
Question 10:
Why might a patient with acquired immune deficiency syndrome (AIDS) be at risk for sodium
imbalance? Answer: They are at increased risk for SIADH. Rationale:
AIDS-related complications, such as opportunistic infections or malignancies, can affect the regulation of ADH,
predisposing patients to SIADH and associated sodium imbalances.
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, lOMoARcPSD|26582732
Question 11:
How does sodium imbalance contribute to clinical manifestations of neurological symptoms?
Answer: It affects the electrochemical gradients required for neuronal activity.
Rationale:
Sodium imbalances disrupt action potentials and cellular osmolality, leading to neurological symptoms such as
confusion, seizures, and altered mental status.
Sodium Deficit (Hyponatremia)
Question 12:
What is the primary laboratory criterion for diagnosing hyponatremia?
Answer: Serum sodium level less than 135 meq/L. Rationale:
Hyponatremia is defined as a serum sodium level below the normal range, which disrupts fluid and electrolyte balance.
Question 13:
What are common causes of sodium loss leading to hyponatremia?
Answer: Use of diuretics, loss of gastrointestinal (GI) fluids, renal disease, and adrenal insufficiency.
Rationale:
These conditions or interventions can lead to significant sodium loss, resulting in an imbalance.
Question 14:
Which conditions or treatments can lead to a gain of water, causing hyponatremia?
Answer: Excessive administration of D5W, water supplements for hypotonic tube feedings, SIADH, medications like
oxytocin, and psychogenic polydipsia.
Rationale:
Water gain dilutes serum sodium, lowering its concentration and contributing to hyponatremia.
Question 15:
What are typical signs and symptoms of hyponatremia?
Answer: Anorexia, nausea, vomiting, headache, lethargy, confusion, muscle cramps, weakness, and seizures.
Rationale:
These symptoms arise from cellular swelling and the impact of sodium imbalance on neuromuscular and brain function.
Question 16:
What key laboratory findings indicate hyponatremia?
Answer: Decreased serum and urine sodium, decreased urine specific gravity, and decreased osmolality.
Rationale:
These findings reflect the body’s impaired ability to retain or properly balance sodium levels.
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, lOMoARcPSD|26582732
Question 17:
Why are patients with heart failure at risk for developing hyponatremia?
Answer: Sodium loss occurs due to hyperglycemia and fluid retention associated with heart failure.
Rationale:
The interplay of fluid shifts and hormonal regulation in heart failure contributes to sodium imbalance.
Question 18:
How might hyponatremia affect cardiovascular parameters?
Answer: It can lead to an increased pulse and decreased blood pressure.
Rationale:
Fluid shifts from hyponatremia can decrease blood volume, resulting in compensatory tachycardia and hypotension.
Sodium Excess (Hypernatremia)
Question 19:
What is the primary laboratory criterion for diagnosing hypernatremia?
Answer: Serum sodium level greater than 145 meq/L. Rationale:
Hypernatremia is defined as a serum sodium level above the normal range, which can occur due to water loss or
excessive sodium gain.
Question 20:
What conditions are associated with fluid deprivation leading to hypernatremia?
Answer: Patients who cannot respond to thirst, hypertonic tube feedings without water, and diabetes insipidus.
Rationale:
Inadequate water intake or loss of free water contributes to a relative excess of sodium in the body.
Question 21:
What are the neurological symptoms commonly seen in hypernatremia?
Answer: Hallucinations, lethargy, restlessness, irritability, and seizures.
Rationale:
Neurological symptoms result from cellular dehydration due to water shifting out of brain cells.
Question 22:
What are common causes of sodium gain leading to hypernatremia?
Answer: Excess corticosteroids, sodium bicarbonate or chloride administration, and saltwater ingestion.
Rationale:
These factors increase sodium levels in the body, leading to hypernatremia.
Downloaded by NELSON KIIRU ()
Electrolyte Imbalances Exam 1 practice questions
chapter 10 rationale part 2 electrolytes
Med surg (Jersey College Nursing School)
Question 1:
What is the primary determinant of extracellular fluid (ECF) volume?
Answer: Sodium (Na+).
Rationale:
Sodium is the most abundant electrolyte in the ECF and plays a critical role in determining ECF volume and osmolality.
Its high concentration and inability to easily cross the plasma membrane contribute to its influence on water
distribution.
Question 2:
What mechanisms regulate sodium levels in the body?
Answer: ADH, thirst, and the renin–angiotensin–aldosterone system.
Rationale:
These mechanisms work together to maintain sodium balance. ADH regulates water retention, thirst drives fluid intake,
and the renin–angiotensin–aldosterone system adjusts sodium reabsorption in the kidneys.
Question 3:
Why is sodium important in muscle contraction and nerve impulse transmission?
Answer: Sodium establishes the electrochemical state necessary for these processes.
Rationale:
Sodium ions play a key role in generating action potentials and maintaining membrane potential, which are essential for
muscle contraction and nerve signal transmission.
Question 4:
How does a loss or gain of sodium typically affect water balance in the body?
Answer: It is usually accompanied by a loss or gain of water. Rationale:
Sodium directly influences water movement due to its osmotic properties. Changes in sodium levels lead to shifts in
water distribution to maintain osmotic equilibrium.
Question 5:
What condition is associated with the oversecretion of antidiuretic hormone (ADH)? Answer:
Syndrome of inappropriate secretion of antidiuretic hormone (SIADH).
Downloaded by NELSON KIIRU ()
, lOMoARcPSD|26582732
Rationale:
SIADH occurs when excessive ADH is secreted, leading to water retention and dilutional hyponatremia. It is triggered by
factors like brain injury, malignancies, and certain medications.
Question 6:
Which patients are at risk for developing SIADH?
Answer: Older adults, patients with brain tumors or pulmonary malignancies, those on mechanical ventilation, and
individuals taking ssris.
Rationale:
These conditions or treatments can disrupt the regulation of ADH, leading to inappropriate secretion and subsequent
sodium imbalance.
Question 7:
What happens when circulating plasma osmolality decreases?
Answer: ADH is released from the posterior pituitary.
Rationale:
ADH secretion is triggered by a drop in plasma osmolality, blood volume, or blood pressure to conserve water and
restore balance.
Question 8:
How does SIADH affect sodium levels?
Answer: It causes hyponatremia due to water retention and dilution of sodium in the plasma.
Rationale:
The excess ADH promotes water reabsorption in the kidneys, diluting sodium and lowering its concentration in the ECF.
Question 9:
What are the two most common sodium imbalances?
Answer: Sodium deficit (hyponatremia) and sodium excess (hypernatremia).
Rationale:
These imbalances occur when sodium levels fall below or exceed the normal range of 135–145 meq/L, impacting fluid
balance and cellular function.
Question 10:
Why might a patient with acquired immune deficiency syndrome (AIDS) be at risk for sodium
imbalance? Answer: They are at increased risk for SIADH. Rationale:
AIDS-related complications, such as opportunistic infections or malignancies, can affect the regulation of ADH,
predisposing patients to SIADH and associated sodium imbalances.
Downloaded by NELSON KIIRU ()
, lOMoARcPSD|26582732
Question 11:
How does sodium imbalance contribute to clinical manifestations of neurological symptoms?
Answer: It affects the electrochemical gradients required for neuronal activity.
Rationale:
Sodium imbalances disrupt action potentials and cellular osmolality, leading to neurological symptoms such as
confusion, seizures, and altered mental status.
Sodium Deficit (Hyponatremia)
Question 12:
What is the primary laboratory criterion for diagnosing hyponatremia?
Answer: Serum sodium level less than 135 meq/L. Rationale:
Hyponatremia is defined as a serum sodium level below the normal range, which disrupts fluid and electrolyte balance.
Question 13:
What are common causes of sodium loss leading to hyponatremia?
Answer: Use of diuretics, loss of gastrointestinal (GI) fluids, renal disease, and adrenal insufficiency.
Rationale:
These conditions or interventions can lead to significant sodium loss, resulting in an imbalance.
Question 14:
Which conditions or treatments can lead to a gain of water, causing hyponatremia?
Answer: Excessive administration of D5W, water supplements for hypotonic tube feedings, SIADH, medications like
oxytocin, and psychogenic polydipsia.
Rationale:
Water gain dilutes serum sodium, lowering its concentration and contributing to hyponatremia.
Question 15:
What are typical signs and symptoms of hyponatremia?
Answer: Anorexia, nausea, vomiting, headache, lethargy, confusion, muscle cramps, weakness, and seizures.
Rationale:
These symptoms arise from cellular swelling and the impact of sodium imbalance on neuromuscular and brain function.
Question 16:
What key laboratory findings indicate hyponatremia?
Answer: Decreased serum and urine sodium, decreased urine specific gravity, and decreased osmolality.
Rationale:
These findings reflect the body’s impaired ability to retain or properly balance sodium levels.
Downloaded by NELSON KIIRU ()
, lOMoARcPSD|26582732
Question 17:
Why are patients with heart failure at risk for developing hyponatremia?
Answer: Sodium loss occurs due to hyperglycemia and fluid retention associated with heart failure.
Rationale:
The interplay of fluid shifts and hormonal regulation in heart failure contributes to sodium imbalance.
Question 18:
How might hyponatremia affect cardiovascular parameters?
Answer: It can lead to an increased pulse and decreased blood pressure.
Rationale:
Fluid shifts from hyponatremia can decrease blood volume, resulting in compensatory tachycardia and hypotension.
Sodium Excess (Hypernatremia)
Question 19:
What is the primary laboratory criterion for diagnosing hypernatremia?
Answer: Serum sodium level greater than 145 meq/L. Rationale:
Hypernatremia is defined as a serum sodium level above the normal range, which can occur due to water loss or
excessive sodium gain.
Question 20:
What conditions are associated with fluid deprivation leading to hypernatremia?
Answer: Patients who cannot respond to thirst, hypertonic tube feedings without water, and diabetes insipidus.
Rationale:
Inadequate water intake or loss of free water contributes to a relative excess of sodium in the body.
Question 21:
What are the neurological symptoms commonly seen in hypernatremia?
Answer: Hallucinations, lethargy, restlessness, irritability, and seizures.
Rationale:
Neurological symptoms result from cellular dehydration due to water shifting out of brain cells.
Question 22:
What are common causes of sodium gain leading to hypernatremia?
Answer: Excess corticosteroids, sodium bicarbonate or chloride administration, and saltwater ingestion.
Rationale:
These factors increase sodium levels in the body, leading to hypernatremia.
Downloaded by NELSON KIIRU ()
