EEG in WNV Neuroinvasive Disease

Area of Science:

• Neurology
• Infectious Diseases
• Neurophysiology

Background:

• Neuroinvasive West Nile virus (WNV) is a rare but serious complication of WNV infection, potentially causing meningitis, encephalitis, or paralysis.
• Electroencephalography (EEG) is crucial for detecting nonconvulsive seizures and other abnormalities indicative of cognitive impairment.

Purpose of the Study:

• To characterize specific electroencephalography (EEG) patterns observed in patients with neuroinvasive West Nile virus (WNV) disease.
• To evaluate the utility of EEG in diagnosing and managing WNV neuroinvasive infections.

Main Methods:

• A retrospective chart review of 34 patients with confirmed WNV infection.
• EEG reports were analyzed and categorized based on epileptiform activity, focal slowing, generalized periodic discharges, and frontally predominant generalized rhythmic delta activity.
• Patients with pre-existing EEG abnormalities were excluded.

Main Results:

• Sixty percent of focal EEG abnormalities in the cohort exhibited an anterior predominance, including epileptiform discharges, focal slowing, or frontally predominant generalized rhythmic delta activity.
• Non-epileptiform patterns such as nonspecific slowing and generalized periodic discharges with triphasic morphology were also observed.
• Two patients experienced electrographic seizures, with one originating in the frontocentral region.

Conclusions:

• EEG is valuable in evaluating WNV infections to exclude seizures and other encephalopathic causes.
• While anterior EEG predominance was noted, it may correlate more with encephalopathy than WNV specifically.
• WNV should be considered in patients with encephalitic or meningitic syndromes and abnormal EEG findings, especially with anterior predominant changes.