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Everything You Need to Know for Fluid and Electrolytes NCLEX Questions

Reviewing all the information you’ve learned in nursing school really is a daunting task when you’re trying to prepare for the NCLEX exam. Information overload can quickly overwhelm you, especially when you aren’t sure where to start. This is why we suggest going section by section as it helps you digest and retain information much better than hopping around to various areas each day. 

For this article, we’re going to focus on the area of fluid and electrolytes. We created some fluid and electrolytes NCLEX questions with a detailed study guide to help you focus on this specific area of nursing knowledge. 

We’ll begin by breaking down fluid and electrolyte basics, ranges, and how to treat imbalances. Then we’ll finish with some fluid and electrolytes NCLEX questions to challenge you as well as get you in a state of confidence to take on the NCLEX exam.

What’s the Role of Fluid and Electrolytes in the Body?

Fluids and electrolytes play a vital role in your body’s homeostasis and functioning. When fluid volumes get too high or too low, the electrolyte levels in the body become unbalanced. This can lead to too much or too little of these important minerals. 

It’s imperative electrolytes stay within normal ranges as they act as tiny messengers within the body, helping organs, cells, and nerves communicate with one another through their positive or negative electrical charge. Levels that are too high or too low can have drastic effects on the body’s ability to function properly. 

For fluid and electrolytes NCLEX questions, remember the following regarding the role of electrolytes:

  • Remove waste from cells
  • Bring nutrients into cells
  • Ensure the heart, muscles, and nerves are working smoothly
  • Balance fluid and pH levels

Electrolytes can be found in foods or drinks. So when you become dehydrated or overhydrated, your body’s electrolyte levels are also affected. In addition, things like vomiting, diarrhea, and certain medications can also alter electrolyte levels. When the body is in a state of homeostasis, it does a fantastic job of keeping electrolytes in a therapeutic range.

Fluid and Electrolyte Imbalances Study Guide

Nurse swapping out patient's fluids

Now that you’ve reviewed the role of fluids and electrolytes in the body, let’s dig into fluid volumes and each individual electrolyte. We designed this section to be used as a study guide for fluid and electrolytes NCLEX questions. We’ll touch on everything you need to know for each area. 

Remember that imbalances must be carefully monitored to avoid serious complications that can result. Fluid and electrolyte levels can be either too high or too low and each is treated very differently.


Hypervolemia is often called fluid volume excess or overload because the volume of fluid in the blood plasma increases. When untreated it can cause congestive heart failure, renal failure, premenstrual syndrome (PMS), or hepatic failure.

  • Symptoms: Rapid weight gain, edema of arms and legs, shortness of breath, abdominal swelling, and jugular venous distention
  • Causes: Hypernatremia or excess sodium
  • Nursing management: Fluid or sodium-restricted diet or diuretic, monitor the patient’s intake and output, vital signs, and assess for edema


Hypovolemia is a fluid deficiency in the body. When untreated it can lead to decreased cardiac output, hypovolemic shock, organ failure, and even death.

  • Symptoms: Dizziness, thirst, decreased blood pressure and mean arterial pressure (MAP), weight loss, syncope, and increased heart rate
  • Causes: Hemorrhage, vomiting, diarrhea, or dehydration 
  • Nursing management: Monitor vital signs and MAP, increase fluid intake orally or with IV fluids, and understand that blood products may be necessary depending on the cause


Sodium reflects changes in fluid status. A blood sodium level that’s too high is called hypernatremia and a level that’s too low is called hyponatremia.

Sodium level normal range: 135-145 mEq/L


  • Symptoms: Thirst, dry mucous membranes, edema, confusion, and hyperreflexia
  • Causes: Increased sodium levels, excessive heat, Cushing’s syndrome, diaphoresis, diarrhea, or dehydration
  • Nursing management: Monitor vital signs, monitor edema, and IV fluids


  • Symptoms: Muscle weakness, neurological deficits, seizure, or headache
  • Causes: Renal failure, heart failure, Addison’s disease, hypothyroidism, or cirrhosis
  • Nursing management: IV sodium, fluid restrictions, seizure precautions, and treat the underlying condition


Potassium stimulates muscle contractions and brain activity. A blood potassium level that’s too high is called hyperkalemia and a level that’s too low is called hypokalemia.

Potassium level normal range: 3.7-5.2 mEq/L


  • Symptoms: Muscle weakness, paralysis, cardiac arrhythmias, and hyperreflexia
  • Causes: Renal disease, burns, metabolic acidosis, or medication side effect
  • Nursing management: Dialysis, cardiac assessments, medication, reduced potassium diet


  • Symptoms: Hypoventilation, palpitations, rhabdomyolysis, and cramping
  • Causes: Laxatives, corticosteroids, diabetic ketoacidosis 
  • Nursing management: Vital signs, respiratory and cardiac assessments, potassium supplement and increase foods rich in potassium 


Calcium plays an important role in bone and tooth health as well as muscle contractility. A blood calcium level that’s too high is called hypercalcemia and a level that’s too low is called hypocalcemia.

Calcium level normal range: 8.5-10.6 mg/dL


  • Symptoms: Hyperparathyroidism, multiple myeloma, breast cancer, and vitamin D toxicity
  • Causes: Paresthesia, ileus, constipation, and bone pain
  • Nursing management: Low calcium diet, hemodialysis, and prevent falls


  • Symptoms: Bronchospasm, muscle aches, arrhythmias, and tetany
  • Causes: Vitamin D deficiency, hypoparathyroidism, eating disorders, and pancreatitis
  • Nursing management: Monitor vital signs, respiratory, and cardiac status


Magnesium is important for heart and neuron function. A blood magnesium level that’s too high is called hypermagnesemia and a level that’s too low is called hypomagnesemia.

Magnesium level normal range: 1.7-2.2 mg/dL


  • Symptoms: Nausea, vomiting, respiratory paralysis, arrhythmias, and CNS depression
  • Causes: Renal failure or hypothyroidism
  • Nursing management: Dialysis or calcium gluconate, CNS, cardiac, and respiratory assessments


  • Symptoms: Arrhythmias, lethargy, tetany, and tremors
  • Causes: Uncontrolled diabetes, Crohn's disease, severe burns, and hypoparathyroidism
  • Nursing management: Monitor cardiac status, IV fluids, and magnesium supplement


Chloride is responsible for maintaining blood pressure and blood volumes within the body’s cells. A blood chloride level that’s too high is called hyperchloremia and a level that’s too low is called hypochloremia.

Chloride level normal range: 97-107 mEq/L


  • Symptoms: Pitting edema, thirst, Kussmaul’s breathing, dyspnea, tachypnea, and hypertension
  • Causes: Dehydration, renal disease, diabetes, hypernatremia, and hyperparathyroidism
  • Nursing management: Monitor edema, respiratory status, and slowly increase fluid intake


  • Symptoms: Hyponatremia, respiratory depression, increased temperature, and muscle spasms
  • Causes: Hypoventilation, cystic fibrosis, respiratory acidosis, and metabolic alkalosis
  • Nursing management: Monitor respiratory status and chloride supplementation


Phosphate is necessary for building strong teeth and bones. Also, it helps muscle contractility and nerve function. A blood phosphate level that’s too high is called hyperphosphatemia and a level that’s too low is called hypophosphatemia.

Phosphate level normal range: 0.81-1.45 mmol/L


  • Symptoms: Muscle cramping, bone weakness, and severe itching
  • Causes: Diabetic ketoacidosis, hypoparathyroidism, infection, septic shock, and renal disease
  • Nursing management: Dietary restriction of phosphate


  • Symptoms: Weak bones, arrhythmias, respiratory alkalosis, and confusion
  • Causes: Hyperparathyroidism, severe burns, diarrhea, alcoholism, and diuretics
  • Nursing management: Phosphate supplementation and an increase in dietary phosphate

Sample Fluid and Electrolytes NCLEX Questions

Nurse on fluid and electrolyte floor

Now that you have a thorough understanding of how fluids and electrolytes work in the body, let’s apply that knowledge with some practice fluid and electrolytes NCLEX questions. Practice questions are a key way to prepare yourself for the NCLEX exam.

Fluid and Electrolytes NCLEX Question #1

Which of the following symptoms is associated with hyponatremia?

  1. Respiratory crackles
  2. Positive Chvostek's sign and Trousseau's sign
  3. Headache
  4. Increased deep tendon reflexes

Answer: C — Headaches are a symptom of decreased serum sodium levels. Respiratory crackles and a positive Chvostek’s sign or Trousseau’s sign aren’t indicative of hyponatremia. In addition, deep tendon reflexes are depressed, not increased, with hyponatremia due to neurological deficits.

Fluid and Electrolytes NCLEX Question #2

You are the health care provider caring for a patient with hypermagnesemia. Which of the following etiologies isn’t associated with hypermagnesemia?

  1. Cardiac arrhythmias
  2. Digoxin toxicity
  3. Hypothyroidism
  4. Renal failure

Answer: B — Digoxin toxicity is associated with low levels of serum magnesium, not high levels. Cardiac arrhythmias, hypothyroidism, and renal failure are all causes of hypermagnesemia.

Fluid and Electrolytes NCLEX Question #3

What type of solution isn’t appropriate to give a patient experiencing hypovolemia?

  1. Dextrose 5% in 0.45% NaCl 
  2. Colloid solution
  3. Hypotonic solution
  4. Isotonic solution

Answer: B — Colloid solutions generally aren’t used for hypovolemia. Dextrose, hypotonic solutions, and isotonic solutions are used for different types of hypovolemia.

Fluid and Electrolytes NCLEX Question #4

Your patient had an early morning laboratory draw and you have just received the lab results. Which of the following laboratory values is the most concerning to you?

  1. Serum chloride 97 mEq/L
  2. Serum calcium 10.7 mEq/L
  3. Serum sodium 146 mEq/L
  4. Serum magnesium 0.9 mEq/L

Answer: D — While A, B, and C are at the upper or lower end of the normal range, a serum magnesium level this low puts the patient at risk of life-threatening arrhythmias and ECG changes. Therefore, you must prioritize that the magnesium level should be treated immediately.

Develop Good Study Habits Early to Pass the NCLEX Exam

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When you’re studying for fluid and electrolytes NCLEX questions, be sure you’re developing a solid routine rooted in good study habits. One of the best and most enjoyable ways to do this is to join the Daily NCLEX Challenge. We aim to make NCLEX prep something you look forward to, not something you dread.

Our premium version offers a healthy dose of competition where you can compete against your fellow nursing students. Each day as you answer more questions correctly, you move up our leaderboard and get the chance to compete for some fun nursing-related prizes (and bragging rights of course).

But no matter whether you choose the premium or our free version, both come with a complimentary practice question delivered straight to your inbox every day. Make studying for fluid and electrolytes NCLEX questions a breeze with the Daily NCLEX Challenge.

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