When preparing for the NCLEX, electrolyte imbalances are one of the most tested topics—and for good reason. Electrolytes like sodium, potassium, calcium, and magnesium play critical roles in nerve conduction, muscle function, hydration, and acid-base balance. Even small fluctuations can lead to life-threatening complications.

In this blog post, we’ll explore the most common electrolyte imbalances, how to identify them, and what interventions every nurse should know. Whether you’re reviewing for the NCLEX or brushing up your clinical skills, this breakdown will give you the edge.

1. Hyponatremia (Low Sodium)

Normal Range: 135–145 mEq/L
Causes:

• Diuretics
• Vomiting/diarrhea
• SIADH
• Excessive water intake

Signs & Symptoms:

• Confusion
• Headache
• Seizures
• Muscle weakness
• Nausea

Nursing Interventions:

• Monitor I&O and daily weights
• Restrict fluids if caused by fluid overload
• Administer hypertonic saline cautiously (3% NaCl)
• Seizure precautions

2. Hypernatremia (High Sodium)

Causes:

• Dehydration
• Excess salt intake
• Diabetes insipidus
• Fever

Signs & Symptoms:

• Thirst
• Dry mucous membranes
• Restlessness
• Seizures
• Elevated temp

Nursing Interventions:

• Administer hypotonic IV fluids (0.45% NaCl)
• Monitor neuro status
• Encourage oral fluids
• Seizure precautions

3. Hypokalemia (Low Potassium)

Normal Range: 3.5–5.0 mEq/L
Causes:

• Diuretics
• Vomiting
• NG suctioning
• Diarrhea

Signs & Symptoms:

• Muscle weakness
• Fatigue
• Dysrhythmias
• Decreased bowel motility

Nursing Interventions:

• Administer oral or IV potassium (never IV push)
• Monitor ECG
• Encourage foods high in potassium (bananas, oranges, spinach)

4. Hyperkalemia (High Potassium)

Causes:

• Renal failure
• Potassium-sparing diuretics
• Acidosis
• Tissue damage

Signs & Symptoms:

• Peaked T waves
• Muscle cramps
• Bradycardia
• Cardiac arrest (severe cases)

Nursing Interventions:

• Administer calcium gluconate, insulin with glucose, or sodium polystyrene sulfonate
• Monitor ECG closely
• Avoid potassium-rich foods

5. Hypocalcemia (Low Calcium)

Normal Range: 8.5–10.5 mg/dL
Causes:

• Hypoparathyroidism
• Vitamin D deficiency
• Renal failure
• Pancreatitis

Signs & Symptoms:

• Tingling in lips/fingers
• Muscle spasms
• Positive Chvostek’s and Trousseau’s signs
• Seizures

Nursing Interventions:

• Administer calcium supplements or IV calcium gluconate
• Vitamin D supplementation
• Seizure precautions

6. Hypercalcemia (High Calcium)

Causes:

• Hyperparathyroidism
• Bone cancer
• Prolonged immobilization

Signs & Symptoms:

• Muscle weakness
• Constipation
• Kidney stones
• Lethargy

Nursing Interventions:

• Encourage fluids
• Administer diuretics
• Monitor cardiac rhythm
• Avoid calcium-rich foods

Quick Tips to Remember:

• Sodium = Neuro (mental status changes)
• Potassium = Cardiac (ECG changes)
• Calcium = Muscles & Nerves (spasms, seizures)
• Magnesium = Calmness (too much = depressed reflexes, too little = hyperreflexia)

Why This Matters for the NCLEX

Electrolyte imbalance scenarios appear often on the NCLEX, especially as select-all-that-apply, priority questions, and case studies. Knowing the causes, symptoms, and nursing interventions helps you stay prepared and confident.

Ready to Level Up Your NCLEX Prep?

At Pathways NCLEX Review, we break down complex topics into easy-to-understand lessons, provide test strategies, and support you every step of the way. Whether you’re preparing for your RN or LVN exam, we’ve got your back.

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