A Man with Abnormal Behaviors, Confusion, and Seizure

The patient had discontinued medications and recently experienced a seizure. He had previously received prescriptions for lithium, propranolol, bupropion, clonazepam, buspirone, and gabapentin. Notable findings included a normal thyroid exam, along with persistent tachycardia, ketonuria, and leukocytosis. Brain imaging, electroencephalography, and cerebrospinal fluid studies were unrevealing. Testing identified thyrotoxicosis, with suppressed thyroid-stimulating hormone and a free T4 level of 3.7 ng/dL (reference range, 0.9–1.8).