A 58-year-old female develops acute-onset confusion and lethargy three days after undergoing abdominal surgery. Her serum sodium is 118 mEq/L. She is euvolemic, without signs of fluid overload or dehydration. What is the most appropriate initial management?

The correct answer to the question "A 58-year-old female develops acute-onset confusion and lethargy three days after undergoing abdominal surgery. Her serum sodium is 118 mEq/L. She is euvolemic, without signs of fluid overload or dehydration. What is the most appropriate initial management?" is Option B: Infusion of 3% hypertonic saline.

The other options — A) Fluid restriction to 800 mL/day, C) Administration of oral sodium chloride tablets, D) Initiation of intravenous normal saline at 125 mL/hr — are incorrect for this USMLE Exam Prep question. As explained above: Severe symptomatic hyponatremia (Na < 120 mEq/L with neurological symptoms) requires cautious and slow correction with 3% hypertonic saline to prevent further neurological complications like cerebral…