What is the role of potassium and magnesium in seizure threshold?

• A. High potassium and high magnesium cause seizures
• B. Electrolyte abnormalities (low potassium or low magnesium or other imbalances) can lower seizure threshold; correct deficiencies to help reduce risk.
• C. Potassium and magnesium have no effect on seizures
• D. Magnesium only affects seizures

Answer: (B)

Neurons fire more easily when the surrounding electrolyte balance isn’t right, so potassium and magnesium levels help set seizure threshold. Magnesium acts as a natural brake on excitability by blocking NMDA receptors; when magnesium is low, this brake is released, making neurons more prone to abnormal firing and seizures. Potassium helps maintain the resting membrane potential of neurons; too much or too little potassium can disrupt this balance and tilt neurons toward hyperexcitability, especially in the presence of other electrolyte disturbances. Because seizures are more likely when electrolytes are out of balance, any deficiency or imbalance of these ions can lower seizure threshold, and correcting those deficiencies helps reduce seizure risk. The idea that only magnesium matters or that these ions don’t affect seizures isn’t accurate, and while extreme levels can be dangerous, the general principle is that electrolyte stability supports safer neuronal activity.