Which electrolyte disturbance is commonly associated with cerebral dysfunction in children?

• A. Hyponatremia or hypernatremia
• B. Hyperkalemia
• C. Hypophosphatemia
• D. Hypomagnesemia

Answer: (A)

Sodium imbalances are the most common electrolyte disturbances linked to brain dysfunction in children because sodium sets the osmolality of the extracellular fluid that surrounds brain cells. When sodium is too low (hyponatremia), water shifts into brain tissue, causing cerebral edema, increased intracranial pressure, and neurologic symptoms such as irritability, vomiting, seizures, and even coma. When sodium is too high (hypernatremia), brain cells lose water and shrink, which can irritate or injure neural tissue and also produce confusion, seizures, or coma, especially with rapid changes. The brain’s sensitivity to shifts in osmolality makes hyponatremia or hypernatremia the typical culprits in pediatric cerebral dysfunction.

Hyperkalemia mainly affects cardiac and neuromuscular function rather than brain function directly. Hypophosphatemia can cause weakness and respiratory or metabolic problems due to impaired energy production, not a primary cerebral dysfunction. Hypomagnesemia can contribute to neuromuscular irritability and seizures in some cases, but it is less commonly the direct cause of cerebral dysfunction in children compared with sodium disturbances.