Problem:
A 60-year-old man presents with sleep disturbance and talking to himself at night for the past week. The patient believes that he is blessed with special powers and sent by God to help humankind. His history is significant for 2 similar episodes in his teens and depression in his 30s. His treatment history shows a poor response to lithium and valproate. He is prescribed another antiepileptic medication and told to follow up in 4 weeks. Within a week, his symptoms improve, but he starts complaining of nausea, dizziness, fatigue, and increased lethargy. Which of the following is the most likely cause of this patient's symptoms? A. Hyponatremia B. Hypocalcemia C. Hypernatremia D. Hypomagnesemia