Fluid and Electrolyte Review: NCLEX Priorities
Hyponatremia, hypernatremia, hyperkalemia, hypokalemia, hypocalcemia: signs, causes, treatment.
Electrolyte imbalances are NCLEX staples. Quick reference of the most-tested.
Hyponatremia (<135)
Causes: SIADH, diuretics, HF, cirrhosis, water intoxication. Signs: confusion, seizures. Correct slowly (no more than 8-12 mEq/24h, risk of central pontine myelinolysis).
Hypernatremia (>145)
Causes: dehydration, DI. Signs: thirst, lethargy. Replace water slowly.
Hyperkalemia (>5)
Causes: renal failure, ACE/ARB, K-sparing. Signs: peaked T waves, then wide QRS. Treatment: calcium gluconate (cardiac protection), insulin + D50, albuterol, kayexalate or patiromer, dialysis in severe.
Hypokalemia (<3.5)
Causes: diuretics, vomiting, diarrhea. Signs: muscle weakness, U waves, arrhythmias. Replace orally or IV (never push).
Hypocalcemia (<8.5)
Causes: hypoparathyroidism, vitamin D deficiency, pancreatitis. Signs: Chvostek's (facial twitch), Trousseau's (carpal spasm). Calcium gluconate IV in severe.
Frequently asked
K+ over 6.5 with ECG changes, first?
Calcium gluconate IV for cardiac membrane stabilization. Then drive K+ in (insulin+D50, albuterol). Then remove (kayexalate, dialysis).
Why correct hyponatremia slowly?
Rapid correction → central pontine myelinolysis. Limit to 8-12 mEq/24h.
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