Viral encephalitides

Viral encephalitides are the result of brain parenchymal infection by a number of different viruses, many of which have similar presentations and imaging features. Specific diagnosis often requires PCR.

For viral infection of the meninges, please refer to the general article on viral meningitis, and, for a broad view on the curriculum of infections of the central nervous system, refer to CNS infectious diseases.

Pathology

The most common causes are :

  • herpes simplex virus (most commonly diagnosed cause )
  • varicella zoster virus (most common associated virus in one series )
  • enterovirus
  • influenza A virus
  • cytomegalovirus (especially in immunocompromised patients)
Etiology

Although there are very many examples, some of the more common and/or important entities include :