Commonly confused in nursing
Hypokalemia vs Hyperkalemia
A potassium of 3.0 and a potassium of 6.5 both trigger lethal dysrhythmias, but the ECG patterns, symptoms, and emergency interventions are mirror opposites. Picking the wrong correction on the NCLEX means choosing the action that kills the patient.
Which One Is It?
1 / 4 · score 0The finding: Prominent U waves
Side-by-side comparison
Side-by-side2 compared
Focus
Dimension
Hypokalemia (< 3.5)
Hyperkalemia (> 5.0)
Pathophysiology & risk
- Loop / thiazide diuretics
- Vomiting, NG suction
- Alkalosis
- insulin administration
- Renal failure
- K⁺-sparing diuretics (spironolactone)
- Crush injury
- acidosis
- transfusion
Signs & symptoms
- Muscle weakness
- Leg cramps
- Hyporeflexia
- ↓ GI motility, ileus
- Muscle weakness
- Muscle twitching, paresthesias
- Ascending flaccid paralysis
- Intestinal cramping, diarrhea
Diagnostics & labs
- Serum K⁺ < 3.5
- flat/inverted T waves
- ★Prominent U waves
- ST depression
- ★Tall peaked T waves (early)
- Serum K⁺ >5.0
- widened QRS, loss of P
Nursing priorities
- Continuous telemetry
- Check Mg²⁺: low Mg blocks K⁺ repletion
- KCl is a vesicant — check IV site
- Continuous telemetry
- Recheck K⁺ 1 hr post-treatment
- Watch rebound hypokalemia after insulin
Treatment / meds
- ★IV KCl ≤10 mEq/hr peripheral
- never IV push
- Always use an infusion pump
- ★IV calcium gluconate first
- Insulin + dextrose, bicarb
- K⁺ binders, dialysis
Patient teaching
- Eat K⁺-rich foods (bananas, potatoes)
- Restrict K⁺-rich foods
- read labels
- Avoid salt substitutes (contain KCl)
Red flags — escalate
- PVCs, V-tach, V-fib
- Potentiates digoxin toxicity
- Bradycardia, heart block, asystole
- Risk spikes when K⁺ > 6.5
Complications
- Cardiac arrest (V-fib)
- paralytic ileus
- Sine-wave QRS pattern
- Cardiac arrest (asystole)
Pathophysiology & risk
Hypokalemia (< 3.5)
- Loop / thiazide diuretics
- Vomiting, NG suction
- Alkalosis
- insulin administration
Hyperkalemia (> 5.0)
- Renal failure
- K⁺-sparing diuretics (spironolactone)
- Crush injury
- acidosis
- transfusion
Signs & symptoms
Hypokalemia (< 3.5)
- Muscle weakness
- Leg cramps
- Hyporeflexia
- ↓ GI motility, ileus
Hyperkalemia (> 5.0)
- Muscle weakness
- Muscle twitching, paresthesias
- Ascending flaccid paralysis
- Intestinal cramping, diarrhea
Diagnostics & labs
Hypokalemia (< 3.5)
- Serum K⁺ < 3.5
- flat/inverted T waves
- ★Prominent U waves
- ST depression
Hyperkalemia (> 5.0)
- ★Tall peaked T waves (early)
- Serum K⁺ >5.0
- widened QRS, loss of P
Nursing priorities
Hypokalemia (< 3.5)
- Continuous telemetry
- Check Mg²⁺: low Mg blocks K⁺ repletion
- KCl is a vesicant — check IV site
Hyperkalemia (> 5.0)
- Continuous telemetry
- Recheck K⁺ 1 hr post-treatment
- Watch rebound hypokalemia after insulin
Treatment / meds
Hypokalemia (< 3.5)
- ★IV KCl ≤10 mEq/hr peripheral
- never IV push
- Always use an infusion pump
Hyperkalemia (> 5.0)
- ★IV calcium gluconate first
- Insulin + dextrose, bicarb
- K⁺ binders, dialysis
Patient teaching
Hypokalemia (< 3.5)
- Eat K⁺-rich foods (bananas, potatoes)
Hyperkalemia (> 5.0)
- Restrict K⁺-rich foods
- read labels
- Avoid salt substitutes (contain KCl)
Red flags — escalate
Hypokalemia (< 3.5)
- PVCs, V-tach, V-fib
- Potentiates digoxin toxicity
Hyperkalemia (> 5.0)
- Bradycardia, heart block, asystole
- Risk spikes when K⁺ > 6.5
Complications
Hypokalemia (< 3.5)
- Cardiac arrest (V-fib)
- paralytic ileus
Hyperkalemia (> 5.0)
- Sine-wave QRS pattern
- Cardiac arrest (asystole)
★ marks the fact that sets a column apart.
Clinical Pearl
Flat T = low K⁺; peaked T = high K⁺ — the T wave mirrors the potassium level.
Play this as a game — free
Drill Hypokalemia vs Hyperkalemia in Swipe Right & Speed Sort. Free to start, no card required.
More commonly confused pairs
Keep going
- GuideHypo vs Hyper: How to Tell Electrolyte Symptoms Apart With One RuleCalcium and magnesium are the brakes: low means hyperexcitable (tingling, tetany, seizures), high means suppressed (weakness, hyporeflexia, lethargy). Potassium sets the resting potential and both directions end in weakness, so the ECG decides. Sodium is water and acts on the brain. The whole chart, derived.
- GuideThe Conditions Nursing Students Always Mix Up (Quiz Yourself)DKA vs HHS, Crohn's vs UC, the potassium ECG changes — the look-alike pairs that cost the most exam points. Take the 8-question discrimination quiz, then drill all 20 pairs free.
- SubjectFluid, Electrolyte & Acid-BaseFluid balance, electrolyte imbalances, IV therapy, and acid-base disorders.
- ComparisonPotassium Imbalance: Hypokalemia vs Hyperkalemia — ECG, Symptoms, InterventionsA potassium of 3.0 and a potassium of 6.5 both trigger lethal dysrhythmias, but the ECG patterns, symptoms, and emergency interventions are mirror opposites. Picking the wrong…
- QuizNursing study gamesSort look-alike conditions and drugs against the clock — the fast way to stop mixing them up.
- TopicHyperkalemiaA potassium of 6.8 mEq/L with peaked T waves means the heart could stop in minutes. The treatment sequence you choose — and the order you choose it in — determines whether it does.