Medisage Academy Quiz!

A 35-year-old woman complains of lightheadedness and palpitations during the day. Symptoms appeared mostly when the sitting position changed to standing. She has a blood pressure of 124/85 mm Hg (lying), 120/80 mm Hg (sitting), and 114/78 mm Hg (standing) and a heart rate of 90 beats/min (lying), 102 beats/min (sitting), and 120 beats/min (standing). Her urine sodium excretion rate is 140 mmol/24 h.