Which electrolyte abnormality requires urgent treatment if potassium is high?

• A. Hypokalemia; risk of seizures.
• B. Hyperkalemia; risk of dangerous arrhythmias.
• C. Hyponatremia; risk of confusion.
• D. Hypercalcemia; risk of stones.

Answer: (B)

Elevated potassium directly threatens the heart’s electrical system, so it can rapidly lead to dangerous arrhythmias or even cardiac arrest if not treated right away. That's why this electrolyte abnormality requires urgent action when potassium is high: stabilizing the heart while lowering potassium levels can prevent life-threatening rhythms. In practice, you’d stabilize the myocardium (calcium), move potassium into cells (insulin with glucose, sometimes beta-agonists), and remove excess potassium (diuretics, dialysis, or potassium binders) as appropriate.

The other listed conditions don’t hinge on a dangerous, high-potassium situation. Low potassium has its own risks but not the same urgent potassium-related cardiac threat, low sodium causes neurologic symptoms, and high calcium presents with stones and other issues rather than the acute cardiac risk seen with hyperkalemia.