In pediatric dehydration due to diarrhea, which electrolyte imbalance is most commonly observed?

• A. Hypernatremia
• B. Hyperkalemia
• C. Hypokalemia
• D. Hyponatremia

Answer: (C)

Potassium is lost in large amounts in the stool during diarrhea, so as dehydration develops the body becomes potassium-depleted, leading to hypokalemia. This matters because potassium is essential for proper muscle function and heart rhythm; low potassium can cause weakness, cramps, reduced gut motility, and even arrhythmias if severe. While hyponatremia can occur with sodium losses and specific fluid choices, and hyperkalemia can occur in other conditions, the most common electrolyte imbalance seen with diarrheal dehydration in children is low potassium. Rehydration plans should include potassium replacement as soon as it’s safe to do so and urine output is adequate.