Epileptic negative myoclonus in herpes simplex virus encephalitis

Area of Science:

• Neurology
• Epileptology
• Infectious Diseases

Background:

• Epileptic negative myoclonus (ENM) is a rare seizure semiology characterized by a brief interruption of muscle activity linked to EEG epileptiform discharges.
• Diagnosis requires polygraphic recording (EEG and EMG) during tonic muscle activity.
• ENM has been historically associated with various chronic epilepsy syndromes.

Observation:

• This study reports a unique case of a patient diagnosed with herpes simplex virus encephalitis.
• The patient exhibited diverse seizure types, notably including epileptic negative myoclonus.
• The clinical presentation was complex, involving neurological deficits secondary to viral encephalitis.

Findings:

• The patient with herpes simplex virus encephalitis presented with epileptic negative myoclonus (ENM).
• This case highlights ENM as a potential seizure manifestation in herpes simplex virus encephalitis.
• Acyclovir treatment resulted in marked improvement of the patient's seizures, including ENM.

Implications:

• This case expands the understanding of seizure semiologies associated with herpes simplex virus encephalitis.
• It underscores the importance of considering viral encephalitis in patients presenting with unusual seizure types like ENM.
• The positive response to acyclovir suggests a potential role for antiviral therapy in managing seizures in this context.