ABSTRACT
Viral infections of the central nervous system (CNS) often present a diagnostic dilemma. The number of causative agents is vast, much greater than a century ago, when the established etiologies of CNS infections were mainly limited to rabies virus and polio virus. The physical findings of CNS infection are often nonspecific, and initial laboratory results may provide few additional clues as to the etiology. Molecular diagnostic testing has dramatically improved the ability to detect viral CNS infections, but requires expertise in the attributes and limitations of these techniques. Even discriminating infectious from noninfectious causes may be challenging, as metabolic, autoimmune, neoplastic, toxic, and endocrinologic entities may mimic meningitis or encephalitis. CNS infections represent syndromes where close collaboration between clinicians and laboratorians is crucial in providing a rapid diagnostic evaluation and an appropriate interpretation of results.
