Electroencephalography Findings in Adult Patients with West Nile Virus--Associated Meningitis and Meningoencephalitis

Abstract

Eighteen adult patients with serologically confirmed West Nile virus (WNV)-associated meningitis or meningoencephalitis were admitted to our hospital during the 2000 West Nile fever outbreak in Israel. Thirteen of the patients had a more severe and prolonged clinical course, and an electroencephalogram (EEG) was, therefore, requested. A specific EEG pattern was seen in 8 patients, consisting of generalized slowing, which was more prominent over the anterior regions. Generalized slowing that was prominent over the temporal area was seen in 2 patients, and intermittent slowing over the temporal region was seen in 1 patient. Two patients had normal EEG findings. We suggest that WNV meningoencephalitis should be considered in the differential diagnosis of meningitis or meningoencephalitis with a prolonged clinical course and anteriorly predominant slowing on an EEG.

Viral encephalitis: Neuropsychiatric and neurobehavioral aspects

“…Given the critical role of the first two of these areas in frontally-mediated neurobehavioral domains such as executive function, comportment, and motivation [73][74][75][76][77][78], WNV-CNS may result in deficits reflective of injuries to frontal-subcortical circuits that serve these neurobehavioral functions. The electroencephalographic findings reported by Gandelman-Marton et al [72] are consistent with this suggestion, showing a pattern of frontal greater than temporal, parietal, or occipital abnormalities. In patients who fail to recover fully from WNV-CNS involving these areas, a pattern suggestive of predominantly subcortical neurologic disorder, or a frank subcortical dementia, would be a possible outcome.…”

“…Electroencephalographic studies suggest that WNV-CNS that produces meningoencephalitis may produce electrographic seizures, focal sharp waves, and diffuse irregular slow waves [36•], and may affect frontal regions more so than temporal, parietal, or occipital areas [72]. Multiple studies of patients with WNV-CNS with acute flaccid paralysis report electromyographic and nerve conduction studies consistent with axonopathy suggestive of injury to anterior horn cells [35,49,57,62].…”

Neuro-Intensive Care of Patients with Acute CNS Infections

“…EEG abnormalities have been reported in approximately 60 to 90% of patients with WNV encephalitis. The most common finding is the presence of diffuse irregular slow waves, although it has been suggested that the presence of anteriorly predominant slowing may suggest the diagnosis [79]. Triphasic slow waves, generally considered more characteristic of metabolic encephalopathies, have also been reported in WNV encephalitis [80].…”

Manifestations of West Nile neuroinvasive disease

“…Seizures have been infrequently associated with WNE; electroencephalographic patterns are generally characterized by diffuse, non-specific slow-wave abnormalities, though an anterior predominance of slow waves has been suggested as characteristic [81]. Increased intracranial pressure and cerebral edema are infrequently reported.…”