MRCP2-4030
You are presented with a 43-year-old female patient who has been admitted with dehydration and a history of borderline personality disorder, alcohol excess, and three previous upper gastrointestinal bleeds requiring endoscopic intervention. She is currently taking lithium MR 400 mg once daily, omeprazole 40 mg once daily, and thiamine 100 mg twice daily. Upon admission, her renal function and osmolalities were as follows: Na 155 mmol/L, K 4.9 mmol/L, urea 13.0 mmol/L, and creatinine 251 µmol/L. Her plasma osmolality was 329 mmol/kg (275-295 mmol/kg), and urine osmolality was 56 mmol/kg (500-800 mmol/kg). Despite receiving 5% glucose infusions, her renal function has not improved significantly. A water deprivation test with desmopressin was performed, and the pre- and post-desmopressin urine osmolalities were 64 mmol/kg and 72 mmol/kg, respectively. What is the most appropriate treatment for this patient’s likely diagnosis?