Clinical and economic importance of applying the guidelines for the diagnosis of viral encephalitis

Viral encephalitis are diseases with complex diagnostic problems, because symptoms are similar to those of flu syndrome and they will resolve in about a week. Brain involvement and prognosis depend on pathogen and patient immunity. In 2008, the American Society of Infectious Diseases has approved guidelines to guide clinician to an appropriate diagnostic evaluation: clinician should ask specific tests, without resorting to a general request (eg. neurotropic viruses), reducing time and costs of etiologic diagnosis. The guidelines set out methods and the proper timing to execute tests for each virus, indicating when to integrate molecular research with antibody research to avoid false negative results, and how to interpret results. During the period September 2007 - August 2009, microbiology laboratory of San Martino hospital in Genoa has analyzed 300 cerebrospinalis liquor from Liguria with a clinical diagnosis of suspected viral encephalitis.The search for viruses HSV1, HSV2,VZV, EBV,CMV, HHV6,Adenovirus, Enterovirus and JCV was performed by real time PCR. Only 51 liquor were positive (16 HSV1, 5 HSV2, 4 VZV, 17 EBV, 2 CMV, 2 HHV6, 1 Adenovirus, 4 Enterovirus and 4 JCV with 4 coinfection). This study confirms that the percentage of encephalitis with a recognized etiologic agent remains very low, despite the increase in positivity in the last two years.This confirms the importance of applying the guidelines to improve the diagnosis of viral encephalitis.