A 72-year-old man was brought to the emergency department by his daughter. She reported that he had nausea, vomiting, and confusion and had been unwell for the last few days. He had hypertension and heart failure for the previous ten years and was on ACE-inhibitor, beta-blocker and thiazide diuretic.
At triage, the patient’s vital signs were usual: blood pressure 110 over 70 mmHg, heart rate 95/min, respiratory 15/min, temperature 36.1°C and SpO2 100% on room air. He appeared lethargic and walked with an unsteady gait. He had no focal neurological deficit. He had a normal skin turgor and no edema. Postural BP revealed mild orthostatic hypotension. The lab results showed a serum sodium concentration of 115 mEq/L.