An 89-year-old woman was admitted to hospital with new-onset confusion. Her daughter had noticed that she had become increasingly forgetful over the past week and now was no longer orientated to time and place. Her medical history was significant for hypertension, for which she took bendroflumethiazide. On examination, Urine test showed Na 114 mmol/L, K 3.8 mmol/L, Urea 6.8 mmol/L, Creatinine 98 µmol/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.
On neurological examination, 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 Na level of 138 mmol/L. What was the probable cause of the woman’s initial confusion? Why has the patient deteriorated? Source: 100 Cases in Acute Medicine *This case is from…
