Pediatric Fluid & Electrolytes Practice Exam
(Questions 1–150)
1. A 2-year-old child presents with vomiting and diarrhea for 2 days.
Which type of dehydration is most likely if the child has sunken
eyes, poor skin turgor, and dry mucous membranes?
Hypertonic dehydration
Rationale: Hypertonic dehydration occurs when water loss
exceeds sodium loss, commonly seen with prolonged vomiting or
diarrhea leading to concentrated serum sodium levels.
2. A 6-month-old infant weighing 6 kg has lost 10% of body weight
due to diarrhea. What is the degree of dehydration?
Severe dehydration
Rationale: 10% weight loss in infants corresponds to severe
dehydration. Mild is 3–5%, moderate is 6–9%, and severe is
≥10%.
3. Which of the following is the most accurate indicator of fluid
status in children?
Weight change
Rationale: Weight change is the most reliable indicator as it
reflects actual fluid loss or gain, while vital signs may lag.
4. A child presents with hypernatremia. Which symptom is most
concerning?
Seizures
Rationale: Rapidly developing hypernatremia increases the risk
of cerebral edema and seizures.
5. The primary extracellular cation in pediatric patients is:
Sodium (Na⁺)
, Rationale: Sodium is the major extracellular cation, crucial for
fluid balance and osmotic pressure.
6. Which IV fluid is most appropriate for initial resuscitation in a
child with hypovolemic shock?
0.9% Normal Saline (isotonic)
Rationale: Isotonic saline is preferred for rapid intravascular
volume expansion without causing rapid shifts in cellular water.
7. A neonate develops hyponatremia due to excessive free water
intake. What is the most appropriate treatment?
Slow correction with hypertonic saline
Rationale: Rapid correction of hyponatremia can lead to central
pontine myelinolysis; gradual correction is safest.
8. A child with diarrhea has a serum sodium of 148 mEq/L. What
type of dehydration is this?
Hypertonic dehydration
Rationale: Hypernatremia (Na⁺ >145 mEq/L) indicates hypertonic
dehydration.
9. A 4-year-old child with dehydration presents with lethargy,
tachycardia, and hypotension. Which stage of dehydration is this?
Shock (severe dehydration)
Rationale: Lethargy, hypotension, and tachycardia indicate
compromised perfusion and severe dehydration requiring
immediate intervention.
10. How much fluid does a 10 kg child require in 24 hours using
the Holliday-Segar method?
1000 mL
Rationale: 100 mL/kg for the first 10 kg = 10 × 100 = 1000 mL.
, 11. A child is receiving maintenance IV fluids. Which fluid is
recommended for ongoing maintenance?
0.45% Normal Saline with 5% Dextrose
Rationale: Hypotonic saline with dextrose meets both fluid and
caloric requirements safely in children.
12. Which electrolyte abnormality is most commonly associated
with pyloric stenosis?
Hypochloremic metabolic alkalosis
Rationale: Persistent vomiting leads to loss of H⁺ and Cl⁻, causing
metabolic alkalosis with hypochloremia.
13. A child with nephrotic syndrome develops edema. What
fluid shift is primarily responsible?
Movement of fluid from intravascular to interstitial space
Rationale: Hypoalbuminemia decreases oncotic pressure, leading
to edema.
14. A 3-year-old receives 2 liters of hypotonic IV fluid over 12
hours and develops confusion. What is the likely complication?
Hyponatremia
Rationale: Excessive hypotonic fluids can dilute serum sodium,
leading to hyponatremia and cerebral edema.
15. Which lab value indicates metabolic acidosis in a dehydrated
child?
Low bicarbonate
Rationale: Loss of bicarbonate through diarrhea or renal
dysfunction lowers serum HCO₃⁻, resulting in metabolic acidosis.
16. A child with acute gastroenteritis presents with tachycardia,
dry mucous membranes, and capillary refill of 4 seconds. What is
the next priority?
(Questions 1–150)
1. A 2-year-old child presents with vomiting and diarrhea for 2 days.
Which type of dehydration is most likely if the child has sunken
eyes, poor skin turgor, and dry mucous membranes?
Hypertonic dehydration
Rationale: Hypertonic dehydration occurs when water loss
exceeds sodium loss, commonly seen with prolonged vomiting or
diarrhea leading to concentrated serum sodium levels.
2. A 6-month-old infant weighing 6 kg has lost 10% of body weight
due to diarrhea. What is the degree of dehydration?
Severe dehydration
Rationale: 10% weight loss in infants corresponds to severe
dehydration. Mild is 3–5%, moderate is 6–9%, and severe is
≥10%.
3. Which of the following is the most accurate indicator of fluid
status in children?
Weight change
Rationale: Weight change is the most reliable indicator as it
reflects actual fluid loss or gain, while vital signs may lag.
4. A child presents with hypernatremia. Which symptom is most
concerning?
Seizures
Rationale: Rapidly developing hypernatremia increases the risk
of cerebral edema and seizures.
5. The primary extracellular cation in pediatric patients is:
Sodium (Na⁺)
, Rationale: Sodium is the major extracellular cation, crucial for
fluid balance and osmotic pressure.
6. Which IV fluid is most appropriate for initial resuscitation in a
child with hypovolemic shock?
0.9% Normal Saline (isotonic)
Rationale: Isotonic saline is preferred for rapid intravascular
volume expansion without causing rapid shifts in cellular water.
7. A neonate develops hyponatremia due to excessive free water
intake. What is the most appropriate treatment?
Slow correction with hypertonic saline
Rationale: Rapid correction of hyponatremia can lead to central
pontine myelinolysis; gradual correction is safest.
8. A child with diarrhea has a serum sodium of 148 mEq/L. What
type of dehydration is this?
Hypertonic dehydration
Rationale: Hypernatremia (Na⁺ >145 mEq/L) indicates hypertonic
dehydration.
9. A 4-year-old child with dehydration presents with lethargy,
tachycardia, and hypotension. Which stage of dehydration is this?
Shock (severe dehydration)
Rationale: Lethargy, hypotension, and tachycardia indicate
compromised perfusion and severe dehydration requiring
immediate intervention.
10. How much fluid does a 10 kg child require in 24 hours using
the Holliday-Segar method?
1000 mL
Rationale: 100 mL/kg for the first 10 kg = 10 × 100 = 1000 mL.
, 11. A child is receiving maintenance IV fluids. Which fluid is
recommended for ongoing maintenance?
0.45% Normal Saline with 5% Dextrose
Rationale: Hypotonic saline with dextrose meets both fluid and
caloric requirements safely in children.
12. Which electrolyte abnormality is most commonly associated
with pyloric stenosis?
Hypochloremic metabolic alkalosis
Rationale: Persistent vomiting leads to loss of H⁺ and Cl⁻, causing
metabolic alkalosis with hypochloremia.
13. A child with nephrotic syndrome develops edema. What
fluid shift is primarily responsible?
Movement of fluid from intravascular to interstitial space
Rationale: Hypoalbuminemia decreases oncotic pressure, leading
to edema.
14. A 3-year-old receives 2 liters of hypotonic IV fluid over 12
hours and develops confusion. What is the likely complication?
Hyponatremia
Rationale: Excessive hypotonic fluids can dilute serum sodium,
leading to hyponatremia and cerebral edema.
15. Which lab value indicates metabolic acidosis in a dehydrated
child?
Low bicarbonate
Rationale: Loss of bicarbonate through diarrhea or renal
dysfunction lowers serum HCO₃⁻, resulting in metabolic acidosis.
16. A child with acute gastroenteritis presents with tachycardia,
dry mucous membranes, and capillary refill of 4 seconds. What is
the next priority?
