Case: Investigations
Patient’s laboratory workup was significant for plasma hypoosmolality (224 mOsm/kg), inappropriate urinary concentration for the given plasma osmolality (405 mOsm/kg), and elevated urinary sodium excretion (83 mmol/L) (Table 2). The patient had normal cortisol and thyroid function tests. A CT scan of the head and chest radiographs showed normal findings. Our patient denied any increased water intake. A review of the patient’s home medications revealed that she was prescribed chlorthalidone and carvedilol for hypertension for the past year.