Electrolyte imbalances are among the most high-yield NCLEX topics every nurse and RN nurse must master. Whether you’re preparing with a nursing bundle or practicing as a registered nurse, knowing the signs, symptoms, and interventions for potassium (K+), sodium (Na+), and calcium (Ca++) disturbances can save lives.
This quick guide breaks it down into a simplified format that’s easy to study, remember, and apply in clinical practice.
🔹 Potassium (K+) Imbalances
Hypokalemia (K+ < 3.5 mEq/L)
Causes: Diuretics, vomiting, diarrhea, NG suction.
Signs:
- Muscle weakness, cramps
- Constipation, decreased bowel sounds
- Weak pulse, arrhythmias (PVCs)
NCLEX Tip: Always monitor EKG and give potassium slowly IV (never push).
Hyperkalemia (K+ > 5.0 mEq/L)
Causes: Renal failure, potassium-sparing diuretics, tissue damage.
Signs:
- Muscle twitching → weakness → paralysis
- Tall peaked T waves on EKG
- Risk for cardiac arrest
Interventions: Kayexalate, insulin + glucose, dialysis if severe.
🔹 Sodium (Na+) Imbalances
Hyponatremia (Na+ < 135 mEq/L)
Causes: SIADH, fluid overload, diuretics.
Signs:
- Confusion, seizures
- Nausea, vomiting
- Weakness, headache
NCLEX Tip: Risk for seizures – implement seizure precautions.
Hypernatremia (Na+ > 145 mEq/L)
Causes: Dehydration, DI, burns.
Signs:
- Thirst, dry mucous membranes
- Restlessness, irritability
- Seizures, coma if severe
Interventions: IV hypotonic fluids, oral fluids.
🔹 Calcium (Ca++) Imbalances
Hypocalcemia (Ca++ < 8.5 mg/dL)
Causes: Hypoparathyroidism, vitamin D deficiency, renal failure.
Signs:
- Muscle cramps, tetany
- Positive Chvostek’s & Trousseau’s signs
- Seizures
NCLEX Tip: Watch for laryngeal spasm → airway emergency.
Hypercalcemia (Ca++ > 10.5 mg/dL)
Causes: Hyperparathyroidism, bone cancer, immobility.
Signs:
- Weakness, fatigue
- Constipation
- Kidney stones
Interventions: Hydration, loop diuretics, bisphosphonates.
🧾 NCLEX Nursing Study Hack
A simple way to remember:
- K+ = Cardiac first (watch EKGs!)
- Na+ = Brain first (watch mental status!)
- Ca++ = Muscles first (watch spasms & weakness!)
This framework is a lifesaver for nursing students studying with a nursing bundle or crash-reviewing before NCLEX exam day.
✅ Final Takeaway for Nurses
Every registered nurse must recognize electrolyte imbalance patterns quickly. For the NCLEX, expect labs, symptoms, and safety interventions. For real-life practice, remember: “Potassium = Pump, Sodium = Neuro, Calcium = Muscles.”
Mastering this guide not only prepares you for the exam but also builds strong clinical reasoning skills as an RN nurse.