A 51-year-old man with seizures and progressive behavioral changes.

A 51-year-old man was admitted for evaluation of new-onset generalized seizures in the context of progressive and significant behavioral change. His medical history was only notable for previous outbreaks of genital herpes. He took no medications. He had occasional social alcohol use and no illicit drug use but was a 35-pack-year current smoker. The patient had no relevant occupational exposure history but had recently traveled to Panama. Initially, the patient's significant other noticed a progressive flattening of his affect. The patient then started to experience episodes of "passing out" that led to injuries prompting ED visits. He was prescribed antiseizure medications and scheduled for an outpatient workup. However, with progressive gait instability, lethargy, and an increase in frequency of generalized seizures, the patient was admitted for treatment of suspected viral encephalitis. Despite initiation of antimicrobial and antiviral therapy, the patient's level of alertness continued to decline, ultimately leading to intubation for airway protection.