Which sign is commonly associated with hypernatremia?

• A. Confusion
• B. Elevated body temperature
• C. Swollen dry tongue
• D. Thirst

Answer: (D)

Hypernatremia raises the concentration of sodium in the blood, increasing plasma osmolality. This activates osmoreceptors in the hypothalamus, triggering the sensation of thirst and prompting the body to conserve water through antidiuretic hormone release. Thirst is the classic signal you’d expect when the body needs to correct a water deficit, making it the most characteristic sign of hypernatremia.

Confusion can occur in severe cases as brain cells shrink from the hyperosmolar state, but it’s a later or less consistent finding. Fever isn’t a defining symptom of hypernatremia, and a swollen dry tongue isn’t typical—dehydration usually causes dryness rather than swelling. So thirst aligns directly with how the body responds to high sodium and fluid imbalance.