NSG 3250 Exam 1 - Adult Health: Fluid and
Electrolyte Balance
Comprehensive Exam 2026
Section 1: Geriatric Population and Dehydration Risk
Question 1:
A nurse is assessing which age group is at highest risk for dehydration. Which population should the
nurse identify as most vulnerable?
A. Infants and toddlers
B. Adolescents
C. Geriatric population
D. Middle-aged adults
ANSWER: C
Rationale:
A. Infants and toddlers are at risk for dehydration but have better physiological mechanisms than the
elderly.
B. Adolescents typically have optimal fluid balance mechanisms and are at lowest risk.
C. CORRECT - The geriatric population is at highest risk for dehydration due to decreased body water
weight, increased adipose tissue, decreased muscle mass, diminished thirst response, and reduced
kidney function.
pmc.ncbi.nlm.nih.gov
D. Middle-aged adults have relatively stable fluid balance mechanisms compared to the elderly.
Question 2:
The nurse understands that the geriatric population is at increased risk for dehydration due to which
physiological changes? (Select all that apply)
A. Increased body water weight
,B. Decreased adipose tissue
C. Decreased muscle mass
D. Increased thirst response
E. Decreased kidney function
ANSWER: C, E
Rationale:
A. Incorrect - Body water weight decreases with age, not increases. Older adults have approximately 10-
15% less total body water than younger adults.
B. Incorrect - Adipose tissue increases with age, not decreases. Fat tissue contains less water than
muscle tissue.
C. CORRECT - Decreased muscle mass occurs with aging, and since muscle contains more water than fat,
this contributes to decreased total body water.
www.healthline.com
D. Incorrect - The thirst response decreases (not increases) with aging, making elderly less likely to
recognize and respond to fluid needs.
E. CORRECT - Decreased kidney function impairs the ability to concentrate urine and conserve water,
increasing dehydration risk.
ctv.veeva.com
Question 3:
When caring for an elderly patient, the nurse recognizes that decreased muscle mass contributes to
dehydration risk because:
A. Muscle tissue holds more water than adipose tissue
B. Muscle tissue requires less oxygen
C. Muscle tissue produces more electrolytes
D. Muscle tissue increases metabolic rate
ANSWER: A
Rationale:
A. CORRECT - Muscle tissue contains approximately 75% water, while adipose tissue contains only about
10-20% water. As muscle mass decreases with age, total body water decreases proportionally.
www.healthline.com
,B. Incorrect - Oxygen requirements are not directly related to fluid balance in this context.
C. Incorrect - Muscle tissue does not produce electrolytes; electrolytes are obtained through diet and
regulated by kidneys.
D. Incorrect - While muscle does affect metabolism, this is not the primary reason for increased
dehydration risk.
Question 4:
A 78-year-old patient is admitted with dehydration. The nurse understands that which factor
contributes MOST significantly to dehydration risk in this population?
A. Increased adipose tissue
B. Blunted thirst response
C. Higher metabolic rate
D. Increased kidney function
ANSWER: B
Rationale:
A. Incorrect - While increased adipose tissue does contribute to lower total body water, it is not the
most significant factor.
B. CORRECT - The blunted (decreased) thirst response is one of the most significant factors contributing
to dehydration in the elderly. Older adults may not feel thirsty even when dehydrated.
www.japi.org
C. Incorrect - Elderly patients typically have decreased (not increased) metabolic rates.
D. Incorrect - Kidney function decreases (not increases) with age, impairing fluid conservation.
Question 5:
The nurse is educating staff about dehydration risk factors in long-term care facilities. Which risk factor
should the nurse emphasize as MOST common?
A. Excessive physical activity
B. Poor oral intake
C. High sodium diet
D. Overhydration
ANSWER: B
, Rationale:
A. Incorrect - Elderly patients in long-term care typically have decreased (not excessive) physical activity.
B. CORRECT - Poor oral intake is the most common risk factor for dehydration in elderly patients,
especially in long-term care settings.
www.mcgill.ca
C. Incorrect - While high sodium can affect fluid balance, it is not the most common cause of
dehydration.
D. Incorrect - Overhydration is the opposite problem and not a risk factor for dehydration.
Section 2: Sodium and Diuresis
Question 6:
The nurse understands that sodium levels decrease with diuresis (urination) because:
A. Sodium is reabsorbed in the collecting duct
B. Sodium is excreted in the urine along with water
C. Sodium production decreases during diuresis
D. Sodium converts to potassium during urination
ANSWER: B
Rationale:
A. Incorrect - While some sodium is reabsorbed, during diuresis more sodium is lost than reabsorbed.
B. CORRECT - During diuresis, sodium is excreted in the urine along with water. Diuretics increase urine
output and sodium excretion, which can lead to hyponatremia.
C. Incorrect - Sodium is not "produced" in the body; it is obtained through diet.
D. Incorrect - Sodium does not convert to potassium; they are separate electrolytes.
Question 7:
A patient receiving furosemide (Lasix) is at risk for which electrolyte imbalance?
A. Hypernatremia
B. Hyponatremia
C. Hyperkalemia
D. Hypercalcemia
ANSWER: B
Electrolyte Balance
Comprehensive Exam 2026
Section 1: Geriatric Population and Dehydration Risk
Question 1:
A nurse is assessing which age group is at highest risk for dehydration. Which population should the
nurse identify as most vulnerable?
A. Infants and toddlers
B. Adolescents
C. Geriatric population
D. Middle-aged adults
ANSWER: C
Rationale:
A. Infants and toddlers are at risk for dehydration but have better physiological mechanisms than the
elderly.
B. Adolescents typically have optimal fluid balance mechanisms and are at lowest risk.
C. CORRECT - The geriatric population is at highest risk for dehydration due to decreased body water
weight, increased adipose tissue, decreased muscle mass, diminished thirst response, and reduced
kidney function.
pmc.ncbi.nlm.nih.gov
D. Middle-aged adults have relatively stable fluid balance mechanisms compared to the elderly.
Question 2:
The nurse understands that the geriatric population is at increased risk for dehydration due to which
physiological changes? (Select all that apply)
A. Increased body water weight
,B. Decreased adipose tissue
C. Decreased muscle mass
D. Increased thirst response
E. Decreased kidney function
ANSWER: C, E
Rationale:
A. Incorrect - Body water weight decreases with age, not increases. Older adults have approximately 10-
15% less total body water than younger adults.
B. Incorrect - Adipose tissue increases with age, not decreases. Fat tissue contains less water than
muscle tissue.
C. CORRECT - Decreased muscle mass occurs with aging, and since muscle contains more water than fat,
this contributes to decreased total body water.
www.healthline.com
D. Incorrect - The thirst response decreases (not increases) with aging, making elderly less likely to
recognize and respond to fluid needs.
E. CORRECT - Decreased kidney function impairs the ability to concentrate urine and conserve water,
increasing dehydration risk.
ctv.veeva.com
Question 3:
When caring for an elderly patient, the nurse recognizes that decreased muscle mass contributes to
dehydration risk because:
A. Muscle tissue holds more water than adipose tissue
B. Muscle tissue requires less oxygen
C. Muscle tissue produces more electrolytes
D. Muscle tissue increases metabolic rate
ANSWER: A
Rationale:
A. CORRECT - Muscle tissue contains approximately 75% water, while adipose tissue contains only about
10-20% water. As muscle mass decreases with age, total body water decreases proportionally.
www.healthline.com
,B. Incorrect - Oxygen requirements are not directly related to fluid balance in this context.
C. Incorrect - Muscle tissue does not produce electrolytes; electrolytes are obtained through diet and
regulated by kidneys.
D. Incorrect - While muscle does affect metabolism, this is not the primary reason for increased
dehydration risk.
Question 4:
A 78-year-old patient is admitted with dehydration. The nurse understands that which factor
contributes MOST significantly to dehydration risk in this population?
A. Increased adipose tissue
B. Blunted thirst response
C. Higher metabolic rate
D. Increased kidney function
ANSWER: B
Rationale:
A. Incorrect - While increased adipose tissue does contribute to lower total body water, it is not the
most significant factor.
B. CORRECT - The blunted (decreased) thirst response is one of the most significant factors contributing
to dehydration in the elderly. Older adults may not feel thirsty even when dehydrated.
www.japi.org
C. Incorrect - Elderly patients typically have decreased (not increased) metabolic rates.
D. Incorrect - Kidney function decreases (not increases) with age, impairing fluid conservation.
Question 5:
The nurse is educating staff about dehydration risk factors in long-term care facilities. Which risk factor
should the nurse emphasize as MOST common?
A. Excessive physical activity
B. Poor oral intake
C. High sodium diet
D. Overhydration
ANSWER: B
, Rationale:
A. Incorrect - Elderly patients in long-term care typically have decreased (not excessive) physical activity.
B. CORRECT - Poor oral intake is the most common risk factor for dehydration in elderly patients,
especially in long-term care settings.
www.mcgill.ca
C. Incorrect - While high sodium can affect fluid balance, it is not the most common cause of
dehydration.
D. Incorrect - Overhydration is the opposite problem and not a risk factor for dehydration.
Section 2: Sodium and Diuresis
Question 6:
The nurse understands that sodium levels decrease with diuresis (urination) because:
A. Sodium is reabsorbed in the collecting duct
B. Sodium is excreted in the urine along with water
C. Sodium production decreases during diuresis
D. Sodium converts to potassium during urination
ANSWER: B
Rationale:
A. Incorrect - While some sodium is reabsorbed, during diuresis more sodium is lost than reabsorbed.
B. CORRECT - During diuresis, sodium is excreted in the urine along with water. Diuretics increase urine
output and sodium excretion, which can lead to hyponatremia.
C. Incorrect - Sodium is not "produced" in the body; it is obtained through diet.
D. Incorrect - Sodium does not convert to potassium; they are separate electrolytes.
Question 7:
A patient receiving furosemide (Lasix) is at risk for which electrolyte imbalance?
A. Hypernatremia
B. Hyponatremia
C. Hyperkalemia
D. Hypercalcemia
ANSWER: B
