Patient history: An 89-year-old woman was admitted to the hospital with new-onset confusion. Her daughter had noticed that she had become increasingly forgetful over the past week and was no longer orientated to time and place. Her medical history was significant for hypertension, for which she took bendroflumethiazide. Examination: The patient’s urine dip was normal, and her inflammatory markers were not elevated. Laboratory investigations Sodium: 114 mmol/L Potassium: 3.8 mmol/L Urea: 6.8 mmol/L Creatinine: 98 mmol/L The patient was given 4 L of 0.9% saline over the next 24 hours.
The following morning, she became more confused, drowsy, and dysarthric. When a neurological examination was performed, she had reduced power throughout all muscle groups, and there were increased tone and brisk reflexes in the lower limbs. Her blood tests showed a sodium level of 138 mmol/L. What was the…
