What is the role of herpes viruses in the etiology of viral meningitis?

Updated: Jul 17, 2018
  • Author: Cordia Wan, MD; Chief Editor: Niranjan N Singh, MBBS, MD, DM, FAHS, FAANEM  more...
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Herpes simplex virus (HSV)-1, HSV-2, varicella-zoster virus (VZV), Ebstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpesvirus-6 collectively cause approximately 4% of cases of viral meningitis, with HSV-2 being the most common offender. The viruses may attack at any time of the year.

Meningitis caused by these viruses is often self-limited. When associated with encephalitis, however, the mortality rate can be high. Early treatment with acyclovir can significantly reduce morbidity.

HSV-1 remains the most common cause of sporadic encephalitis, while HSV-2 infections of CNS mostly are restricted to aseptic meningitis.

HSV-2 genital infection may precede meningitis; sexual contact with actively infected individuals is one of the known risk factors.

In one review, however, only 3 of 23 patients with HSV-2 meningitis had a history of prior genital herpes or had genital lesions noted at the time of presentation. [7] Maternal-fetal transmission of HSV-2 can occur, leading to significant systemic sequelae, including infantile septicemia and death.

EBV, HSV-1, and especially HSV-2 have been associated with Mollaret meningitis, a rare, benign, recurrent meningitis that resolves spontaneously. Mollaret cells (activated monocytes with an atypical appearance of enlarged, bilobed nuclei and amorphous cytoplasm) are found in the CSF usually on the first day of symptoms. Herpesvirus-6, EBV, and the human immunodeficiency virus (HIV; which is not a member of the herpes family) have also been implicated. These viruses are all known to remain latent within the nervous system.

CMV infections occur mostly in immunocompromised hosts. CMV may cause subacute encephalitis in patients with AIDS. Congenital CMV, which is a much more serious form of infection, has significant associated morbidity and mortality.

Childhood or adult chickenpox infections by VZV rarely are complicated by meningitis. Adult zoster involving any dermatome may lead to meningitis or meningoencephalitis.

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