Student MCQs – Fluids and Electrolytes

Which of the following signs is most indicative of dehydration in infants?

• A) Increased urine output

• B) Dry mouth and tongue

• C) Weight gain

• D) Increased tear production

Confirmation: Options B is correct because these signs often occur due to decreased extracellular fluids.

Explanation:

Option A is incorrect because increased urine output is indicative of increased renal perfusion and 

Option C is incorrect because weight gain is indicative of excess extracellular fluid.

Option D is incorrect because decreased tear production is what is indicative of dehydration.

Which of the following assessment methods is commonly used to evaluate dehydration in children?

• A) Checking for a fever

• B) Monitoring blood pressure

• C) Observing skin turgor

• D) Measuring respiratory rate

Option C is correct because when a person is dehydrated they tend to have decreased skin turgor as decreased ECF leads to decreased elasticity. 

Option B is also correct because decreased blood pressure can be due to decreased blood volume. 

Explanation:

Option A is incorrect because a fever is not indicative of dehydration. 

Option D is incorrect because respiratory rate is not one of the factors assessed when measuring the degree of dehydration. 

Which of the following signs is most indicative of dehydration in infants?

• A) Increased urine output

• B) Dry mouth and tongue

• C) Weight gain

• D) Increased tear production

Confirmation: Options B is correct because these signs often occur due to decreased extracellular fluids.

Explanation:

Option A is incorrect because increased urine output is indicative of increased renal perfusion and 

Option C is incorrect because weight gain is indicative of excess extracellular fluid.

Option D is incorrect because decreased tear production is what is indicative of dehydration.

Which of the following assessment methods is commonly used to evaluate dehydration in children?

• A) Checking for a fever

• B) Monitoring blood pressure

• C) Observing skin turgor

• D) Measuring respiratory rate

Option C is correct because when a person is dehydrated they tend to have decreased skin turgor as decreased ECF leads to decreased elasticity. 

Option B is also correct because decreased blood pressure can be due to decreased blood volume. 

Explanation:

Option A is incorrect because a fever is not indicative of dehydration. 

Option D is incorrect because respiratory rate is not one of the factors assessed when measuring the degree of dehydration. 

Which of the following ions is most critical to monitor due to its potential to cause dangerous cardiac arrhythmias in patients with renal failure? 

1. Sodium (Na⁺) 

2. Calcium (Ca²⁺) 

3. Potassium (K⁺) 

4. Chloride (Cl⁻)

Potassium is the most likely intracellular electrolyte to cause arrhythmia in hyperkalemia, so that is correct. Also, the other electrolytes above are not considered intracellular.

Calcium can also cause arrhythmias but is an extracellular ion. Sodium imbalances would be more likely to cause CNS effects.

Which ion imbalance can affect neuromuscular function and cardiovascular health in patients with renal dysfunction? 

1. Phosphate (PO₄³⁻) 

2. Magnesium (Mg²⁺) 

3. Bicarbonate (HCO₃⁻) 

4. Sulfate (SO₄²⁻)

Only magnesium and phosphate are intracellular ions. 

Magnesium deficiency may manifest as neuromuscular excitability and is associated with ventricular arrhythmias. Hypermagnesemia slows neuromuscular activity and impairs cardiovascular function, with initial signs being conduction defects and bradycardia. Therefore, magnesium is the correct answer.

Phosphate is important for skeletal growth and hypophosphatemia would negatively impact bone growth and maintenance, leading to disorders such as rickets.

Bicarbonate is extracellular and more associated with pH imbalances. I can’t find much information about sulfate as an ion in the body so I don’t think that is correct.

 

What are the electrolyte changes expected in the loss of bile versus small bowel versus diarrhea?

1. Loss of bile: Hyponatremia, hypokalemia, and metabolic acidosis 

2. Loss of small bowel: Hypernatremia, hypokalemia, and metabolic alkalosis 

3. Diarrhea: Hyponatremia, hypokalemia, and metabolic acidosis 

4. Loss of small bowel: Hyponatremia, hyperkalemia, and metabolic alkalosis

 

1. This one is incorrect because bile contains a lot of acid in comparison to bicarbonate which would result in a metabolic alkalosis when lost.

2. This one is incorrect because there is sodium content in small bowel fluid which, when lost, would result in hyponatremia. In addition there are greater bicarbonate levels in small bowel fluid than acid levels which would result in a metabolic acidosis when lost.

3. This one is correct because diarrhea has sodium, potassium, and bicarbonate concentrations that would cause hyponatremia, hypokalemia, and a metabolic acidosis when lost. 

4. This is incorrect because small bowel fluid contains potassium which would result in hypokalemia when lost.

What are the expected electrolyte changes in loss of bile versus small bowel versus diarrhea?

1. Loss of bile: Hypokalemia; Small bowel: Hypernatremia; Diarrhea: Hypocalcemia

2. Loss of bile: Hypochloremia; Small bowel: Hyponatremia; Diarrhea: Hyperkalemia

3. Loss of bile: Hypokalemia; Small bowel: Hyponatremia; Diarrhea: Hypokalemia

4. Loss of bile: Hypernatremia; Small bowel: Hypokalemia; Diarrhea: Hypercalcemia

1. Incorrect: loss of small bowel fluids would cause hyponatremia. Did not discuss calcium changes with diarrhea.

2. Incorrect: diarrhea would result in hypokalemia

3. Correct: these electrolyte disturbances would be seen in the loss of the corresponding fluids.

4. Incorrect: loss of bile would cause hyponatremia. Did not discuss calcium changes with diarrhea.

Which intracellular ion's abnormal levels can lead to significant cardiovascular complications in patients with renal dysfunction?

a. Sodium

b. Potassium

c. Calcium

d. Chloride

Correct Answer: b. Potassium 

Option B is correct because potassium plays a crucial role in regulating heart function and rhythm. Hypokalemia could result in arrhythmias and increased workload on the heart. Hyperkalemia could result in bradycardia or in severe cases, cardiac arrest. The kidney plays a critical role in regulating, metabolizing, and excreting potassium which makes monitoring it in kidney dysfunction very important. 

While monitoring all electrolytes are important for overall health in sick individuals, options A, C, and D are incorrect in this scenario. 

Option A is incorrect because sodium does not have as much of a direct effect on cardiac rhythm. It is more important for regulating fluid balance and blood pressure. 

Option C is incorrect because while it plays an important part in electrical conduction and muscle contraction, it has less of an effect on cardiac arrhythmias for renal patients. 

Option D is incorrect because chloride does not have any direct impacts on cardiovascular health. Chloride is monitored for electrolyte imbalances and acid-base status

Which intracellular ion's imbalance is most likely to cause metabolic acidosis in patients with renal failure?

a. Magnesium

b. Phosphate

c. Potassium

d. Calcium

Correct Answer: b. Phosphate 

Option B is correct because the kidneys play a critical role in metabolising and excreting waste, and phosphate is a key intracellular ion that regulates acid-base status. Phosphate helps create normal pH levels in the body. An accumulation of phosphate due to renal dysfunction can result in an increased concentration of H+ ions, leading to metabolic acidosis. 

Option A is incorrect because magnesium is more related to muscle function in the body rather than acid-base status. 

Option C is incorrect because potassium causes cardiac complications rather than acid-base complications 

Option D is incorrect because calcium imbalances are more related to bone disease rather than acid-base status

Which electrolyte imbalance is commonly seen with bile loss?

• A) Hyperkalemia

• B) Hypokalemia

• C) Hypermagnesemia

• D) Hyponatremia

• A) Hyperkalemia - Incorrect, this is the opposite of what happens

• B) Hypokalemia - Correct, we lose potassium with bile loss because potassium binds to bile salt

• C) Hypermagnesemia - Incorrect, no significant changes in magnesium when there's bile loss 

• D) Hyponatremia - Incorrect, bile is a small volume so when there's a loss of it sodium levels aren't greatly affected

What is a common electrolyte change seen in diarrhea?

• A) Hypochloremia

• B) Hypocalcemia

• C) Hyperkalemia

• D) Hypercalcemia

• ypochloremia - Correct, 

• B) Hypocalcemia - Incorrect, usually due to malabsorption 

• C) Hyperkalemia - Incorrect, hypokalemia is seen with diarrhea

• D) Hypercalcemia - Incorrect, calcium levels are more likely to decrease or are unaffected

Which electrolyte imbalance is most commonly associated with small bowel loss?

• A) Hypernatremia

• B) Hyponatremia

• C) Hyperkalemia

• D) Hypokalemia

Correct Answer: B. Hyponatremia

Confirmation: Hyponatremia is the correct answer as the patient is losing fluid with small bowel loss, implying they are losing electrolytes. Sodium is quite high in the small bowel, 130-140 mEq/L compared to diarrhea's 50-60 mEq/L and similar to bile's 130-145 mEq/L. Compared to other biological fluid losses, small bowel fluid has high sodium concentrations, implying that a loss would likely result in hyponatremia. (Pediatric slides on electrolyte content of various biological fluids)

Explanation: Option is A and C of hypernatremia and hyperkalemia is incorrect as losing fluid would not increase electrolytes here. Option D is incorrect here as the small bowel electrolyte concentration is only 4-6 mEq/L, When compared to diarrhea(40-50 mEq/L) and other biological fluids, the potassium concentration is actually quite low in small bowel fluid.

Which electrolyte imbalance is most commonly associated with loss of bile?

• A) Hyperkalemia

• B) Hypokalemia

• C) Hyperchloremia

• D) Hypochloremia

Correct Answer: D. Hypochloremia

Confirmation: Hypochloremia is the correct answer here as bile has a rather high concentration of chloride ions (95-105 mEq/L) compared to small bowel fluids(40-60 mEq/L) or diarrhea(35-45 mEq/L). Since we are talking about loss of bile, there is a loss of both potassium and chloride. However, bile's potassium levels are comparatively low at 4-6 mEq/L compared to other bodily fluids like saliva(10-20 mEq/L) or diarrhea(40-50 mEq/L), so hypochloremia is more likely in bile loss. (Pediatric slides on electrolyte content of various biological fluids)

Explanation: Option A and C are both increases in electrolytes, and in this case where there is bile loss, we would be seeing a decrease in these electrolytes. Option B. is wrong as dicussed earlier, bile has relatively low concentrations of potassium compared to other bodily fluids when compared to chloride concentrations. So while losing a lot of bile may cause hypokalemia, hypochloremia is more likely specific to bile. 

What is an appropriate fluid choice for pediatric patients who are severely dehydrated or in shock?

1. Administering hypotonic saline solution (0.45% NaCl) 

2. Administering isotonic saline solution (0.9% NaCl) 

3. Administering hypertonic saline solution (3% NaCl) 

4. Administering dextrose 5% in water (D5W)

Answer: B. Administering isotonic saline solution (0.9% NaCl)

Confirmation: Option B is correct because in emergent situations, the goal is to restore the ECF with a bolus of isotonic fluids.

Explanation: 

Option A is incorrect because hypotonic solutions can lead to intracellular fluid shifts. 

Option C is incorrect because hypertonic solutions are not appropriate for routine fluid resuscitation. 

Option D is incorrect because D5W acts as a hypotonic solution once dextrose is metabolized, which can lead to intracellular shifts. 

What is the preferred IV maintenance fluid for a neonate?

a) 0.9% sodium chloride solution 

b) 5% dextrose in water (D5W) 

c) 5% dextrose in 0.45% sodium chloride solution (D5 1/2 NS) 

d) Lactated Ringer's solution

Option C is correct for most neonates in order to provide energy and electrolytes, normal saline for a neonate is too much sodium and their kidneys are not fully developed enough

Option A is incorrect because normal saline is too much sodium for the neonates underdeveloped kidneys, option B is incorrect because it does not provide essential nutrients like sodium and chlorine (D10W is commonly used in the first 48hrs of neonates life), option D is incorrect because LR contains electrolytes not routinely used for neonate maintenance 

For a child aged 3 years, which IV maintenance fluid is commonly recommended?

a) 0.45% sodium chloride solution (1/2 NS) 

b) 0.9% sodium chloride solution (NS) 

c) 5% dextrose in water (D5W) 

d) 5% dextrose in 0.9% sodium chloride solution (D5 NS)

Option D is correct because by age 3 children have developed kidneys and using normal saline is appropriate, this combination gives energy while also preventing hyponatremia 

Option A is incorrect because it is a hypotonic solution and may cause hyponatremia, option B is incorrect because it does not contain dextrose as a form of energy/carbs, option C is incorrect because it lacks essential nutrients like sodium and chloride, could cause hyponatremia 

1. Which fluid is recommended for initial resuscitation in pediatric patients with severe dehydration or shock?

   • A) Dextrose 5% in water

   • B) Normal saline (0.9% sodium chloride)

   • C) Half-normal saline (0.45% sodium chloride)

   • D) Lactated Ringer's solution

Copilot noted the correct answer is choice B, Normal saline. However, I think both B and D, Lactated Ringer’s solution, would be correct. This is because severe dehydration needs to be initially treated with a bolus of isotonic fluids. LR is technically slightly hypotonic, however it is very close to isotonic so I believe it can still be used.  This can be measured by the osmolarity of the fluid compared to blood. Blood= 280-300 mOsm/L, Normal saline= 308 mOsm/L, LR= 272 mOsm/L.

Option A is incorrect because D5W is too hypotonic to be used as initial fluid resuscitation (253 mOsm/L).

Option C is incorrect because ½ NS is also too hypotonic to be used as fluid resuscitation (154 mOsm/L).

1. What is the initial bolus volume for fluid resuscitation in pediatric patients with severe dehydration or shock?

   • A) 5 mL/kg

   • B) 10 mL/kg

   • C) 20 mL/kg

   • D) 30 mL/kg

The correct answer is C, 20 mL/kg. This is the volume for emergent treatment of dehydration when the patient is hemodynamically unstable (shock) with severe dehydration. It should be given over 30-60 minutes and then corrective and maintenance therapy can be initiated.

Option A and B are incorrect because the volume is too small to adequately treat a patient with severe dehydration or shock.  

Option D is incorrect because it is too high of a volume to adequately treat severe hydration or shock.

Which of the following is a common sign of dehydration in infants?

1. A) Increased urination

2. B) Dry mouth and tongue

3. C) Excessive sweating

4. D) High energy levels

Correct Answer: B) Dry mouth and tongue

Confirmation: 

• option B is correct because 

Explanation:

• option A is incorrect because dehydration is often seen in those with decrease in urination of less than 1 mL/kg/hr.

• option C is incorrect because when patients  are dehydrated, they sweat less.

• option D is incorrect because dehydration can cause a pediatric patient to be lethargic.

 

What is a reliable method to assess dehydration in children?

1. A) Measuring body temperature

2. B) Checking skin turgor

3. C) Observing sleep patterns

4. D) Monitoring hair growth

Correct Answer: B) Checking skin turgor

Confirmation: 

• option B is correct because the elasticity of the skin is something that providers use as part of the dehydration assessment protocol.

Explanation:

• option A is incorrect because measuring body temperature wasn’t mentioned in the lecture.

• option C is incorrect because sleep patterns can be impacted by various factors and other illnesses, not just the  level of dehydration in children.

• option D is incorrect because the lecture didn’t mention monitoring for hair growth.

Which of the following intracellular ions must be closely monitored in patients with renal failure or renal dysfunction?

1. A) Sodium and Chloride
   B) Potassium and Phosphorus
   C) Calcium and Magnesium
   D) Iron and Zinc

   

Correct Answer: B) Potassium and Phosphorus

Explanation:

• Correct:

  • Potassium (K) and phosphorus (Phos) are intracellular ions that require careful monitoring in renal failure due to impaired excretion. According to the lecture, "Potassium (K) – intracellular" and "Phosphorus (Phos) – intracellular" must be considered when adjusting dosing in renal failure​.

• Incorrect:

  • A) Sodium and Chloride – Both are not intracellular electrolytes​.

  • C) Calcium and Magnesium – While magnesium is intracellular, calcium regulation is more related to phosphorus levels, and phosphorus has a more direct role in renal dysfunction​.

  • D) Iron and Zinc – Not intracellular ions

    

A pediatric patient with chronic kidney disease (CKD) is found to have an abnormal electrolyte panel. Which of the following electrolyte imbalances is most likely?

1. A) Hypokalemia and hypophosphatemia
   B) Hyperkalemia and hyperphosphatemia
   C) Hypernatremia and hypocalcemia
   D) Hypomagnesemia and hypochloremia

 

Correct Answer: B) Hyperkalemia and hyperphosphatemia

Explanation:

• Correct: The lecture states, "Adjust dosing in renal failure," particularly for "Potassium (K) – intracellular" and "Phosphorus (Phos) – intracellular" due to the kidney's inability to excrete them efficiently​.

• Incorrect:

  • A) Hypokalemia and hypophosphatemia – This is backwards. Would be more more common in malnutrition or diuretic overuse, not renal failure​.

  • C) Hypernatremia and hypocalcemia – Sodium is more related to volume status, and calcium imbalances occur indirectly through phosphorus imbalances​.

  • D) Hypomagnesemia and hypochloremia – Magnesium depletion is more associated with diuretic use, and chloride is more relevant to acid-base imbalances​.

What is the most appropriate IV maintenance fluid for a neonate?

 

• A) 0.9% Normal Saline

• B) D5W with 0.2% NaCl 

• C) D5W with 0.45% NaCl

• D) Lactated Ringer's

B is the correct answer as D5W provides provides dextrose for the neonate while the 0.2% NaCl provides an acceptable level for a neonate who has immature kidneys. Higher percentages are more likely to cause further imbalances.

A and C are incorrect as the percentages of NaCl are higher than needed for the neonate. D contains multiple electrolytes in concentrations than are higher than needed for a neonate for reasons discussed previously.

For a child aged 6 years old, which IV maintenance fluid is generally preferred?

 

• A) 0.9% Normal Saline

• B) D10W

• C) D5W with 0.45% NaCl

• D) D5W with 0.2% NaCl

C is correct as it offers dextrose and a balanced concentration of NaCl (0.45%) that is appropriate for maintenance fluid to avoid hypernatremia.

A is incorrect as it offers an isotonic concentration that is greater than needed in this case. B is incorrect as is offers no electrolyte replenishment. D is incorrect as the concentration of 0.2% NaCl is too low, putting the patient at risk of hyponatremia