Seven cases were found and reviewed in addition to our case. There were 3 males and 5 females. Median age was 55.5 years (Range 37 to 70). The most common indication for rituximab was B-cell lymphoma. Time from rituximab infusion to presentation ranged from 1 to 24 weeks. The most common initial complaints were fever and altered mental status, followed by weakness. Brain MRI demonstrated bilateral thalamic hyperintensities in four patients. In all cases CSF analysis revealed mild lymphocytic pleocytosis with elevated protein, positive WNV polymerase chain reaction, and negative WNV antibody. Treatment consisted of supportive care in six cases, intravenous immunoglobulin (IVIG) plus corticosteroids in one, and WNV-specific IVIG in one. Six cases were fatal, with the other two demonstrating partial recovery, including our case. Of the two cases with improvement, one was treated with IVIG.

WNVND is a rare and serious infection when associated with rituximab therapy. Diagnosis is complicated by absent or delayed development of antibodies. As the differential diagnosis for altered mental status in the setting of immunosuppression is broad, the presence of bilateral thalamic involvement should be a clue to consider WNVND. Prognosis is poor. There is insufficient evidence to recommend the use of corticosteroids or IVIG.