Review Question - QID 204324

A 78 year-old woman is brought to the emergency department by her maid, who found her lethargic and less responsive than usual this morning. The maid had been on vacation for the last week and reports that the woman was alert and active previously. The patient has a past medical history of hypertension and early dementia, and her medications include metoprolol and memantine. Her temperature is 36.8 C, blood pressure 94/60 mmHg, heart rate 96/min, and respiratory rate 16/min. Her blood pressure decreases to 84/50 mmHg while standing. She is lethargic and oriented to person and place only. She has dry oral mucosa and decreased skin turgor. Her heart, lung, and abdominal exams are within normal limits and stool guaiac is negative. Initial labs are as follows:
Sodium 124 mEq/L, potassium 3.4 mEq/L, chloride 95 mEq/L, bicarbonate 31 mEq/L, BUN 28 mg/dL, creatinine 1.0 mg/dL, and glucose 120 mg/dL. ...