What are typical signs of hyponatremia?

• A. Nausea and fatigue
• B. Seizures only in severe cases
• C. Confusion, lethargy, seizures in severe cases; may present with nausea and fatigue
• D. Hypernatremia is common

Answer: (C)

Hyponatremia lowers plasma sodium, which lowers serum osmolality and causes water to move into brain cells. That brain swelling leads to symptoms that range from mild and nonspecific to severe and life-threatening, depending on how fast the sodium drops.

Early signs are often nonspecific, like nausea and fatigue. As hyponatremia becomes more significant or develops quickly, mental status changes such as confusion and lethargy appear. In the most severe cases, seizures can occur due to rapid brain edema. This combination—confusion, lethargy, seizures in severe cases; may present with nausea and fatigue—best captures the range of typical signs across severity levels.

Hypernatremia is not a sign of hyponatremia; it describes the opposite condition (high sodium). The other options are incomplete because they either omit the neurological symptoms or misstate the condition.