A case of herpes simplex encephalitis with periodic lateralized epileptiform discharges

A case of a 50-year-old male with herpes simplex encephalitis was reported. An EEG examination revealed periodic lateralized epileptiform discharges (PLEDs) on the right hemisphere on April 17, 1990. Another EEG performed on April 26 showed PLEDs on the left hemisphere, dominantly on the temporal lobe. On and after May 2, PLEDs have not been detected. SPECT showed hyperperfusion in the right temporal and occipital lobe son April 26. T1 weighted MRI examined on April 18 showed low signal intensity and T2 and proton weighted imagings revealed high signal intensity in the greater part of the right temporal lobe and a similar abnormality in a part of the left temporal lobe. Although the origin of PLEDs is still controversial, these findings suggest that, at least in the case of herpes simplex encephalitis, PLEDs appear in the early progressive stage of the inflammatory lesion.