Published online by Cambridge University Press: 03 November 2020
This 52-year-old man presented to the emergency room with aggressive behavior and emotional lability progressing over the previous three days. He had completed a three-week course of acyclovir for the treatment of herpes simplex encephalitis (HSE) two weeks prior. Other than residual mild memory difficulties, he was fully functional until his more recent behavioral changes. He was afebrile and his vitals were within normal limits. He was irritable and his attention fluctuated. His exam otherwise unremarkable. MRI of the brain with and without contrast was unremarkable. Laboratory results were significant only for mildly increased CSF protein (100 mg/dl normal range: 15–45 mg/dl). Given the concern of HSE relapse, he was placed on acyclovir again.