Typical and Atypical Imaging Features of West Nile Neuroinvasive Disease: A Timely Review

Abstract

West Nile virus is the most common arbovirus in the continental United States and one of the most common throughout the world. Less than 1% of West Nile virus infections result in West Nile neuroinvasive disease. Patients characteristically present with meningitis, encephalitis, or acute flaccid myelitis, but they may have a variable clinical course and corresponding imaging manifestations. The radiologist plays an important role in making this often-elusive diagnosis. Understanding the imaging features of typical and atypical West Nile neuroinvasive disease is crucial to making a timely diagnosis, which can help prevent additional, potentially harmful testing or treatment. In this review, the authors summarize their experience with West Nile neuroinvasive disease imaging during a surge of cases at their institution.Learning Objective: To identify the typical and atypical imaging appearances of West Nile virus neuroinvasive disease, to understand the differential diagnosis when a patient presents with typical imaging features of West Nile virus infection, and to recognize the environmental factors responsible for seasonal variations in West Nile virus infections