**2. Objectives and methods**

We extracted the clinical records of the 105 patients diagnosed with acute viral encephalitis/ encephalopathy in 2002―2012 from the medical records of St. Mary's Hospital, Kurume

© 2013 Shoji et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

City. Our hospital is located in southwestern Japan and provides emergency medical care for approximately 500,000 local residents. The diagnostic criteria for each viral agent in the patients' clinical charts were, in principle, dependent on polymerase chain reaction (PCR) positivity in cerebrospinal fluid (CSF) or serologic four fold increases in pair sera or CSFs. HSE was diagnosed by clinical symptoms, CSF, magnetic resonance imaging (MRI), electro‐ encephalogram (EEG), and virologic tests such as herpes simplex virus (HSV) PCR in CSF and enzyme immunoassay (EIA) IgG IgM antibodies. VZV-associated encephalitis was mainly diagnosed by characteristic skin eruptions. JE in Japan is seen from August to Sep‐ tember. The diagnosis of JE is established by complement fixation (CF) or hemagglutination inhibition (HI) test in pair sera, or PCR for JE virus. FluE is defined as persistent conscious‐ ness impairment over 24 hours following an influenza infection; delirium or convulsive seiz‐ ures due to high fever and metabolic disorders are excluded (Japanese guidlines for FluE, 2009).The clinical forms of FluE are divided into the status epilepticus type, thalamic type, acute necrotizing encephalopathy, hemorrhagic shock and encephalopathy, Reye syndrome, and others in which no CSF pleocytosis, high concentration of IL-6 and negative PCR in CSF for influenza virus are usually observed. Non-herpetic limbic encephalitis is identified by MRI findings in bilateral limbic systems and negative HSV PCR or EIA antibodies (Ichiyama T, 2008, Shoji et al, 2012). As for anti-N-methyl-D-aspartate receptor (anti-NMDAR) ence‐ phalitis or encephalopathy, ovarian teratoma is usually found, except for pedriatric cases (Dalmau et al, 2007, 2011). Patients with viral-related acute disseminated encephalomyelitis (ADEM) were diagnosed as having disseminated neurologic lesions following suspected vi‐ ral infections.

but the EIA IgG for HSV showed a significant increase, and his MRI DW revealed high in‐ tensities in the right limbic regions (Fig.2). Four patients with VZV-associated encephalitis were diagnosed by the characteristic skin eruptions. Of CMV, EBV, and HHV-6 associated with encephalitis or encephalopathy, the case of a one-year-old girl with probable HHV-6 encephalopathy was identified (Fig. 3). She was admitted to our hospital with a high fever, tonic seizures, and consciousness impairment. Although apparent clinical symptoms of ex‐ anthem subitum were not observed, her serum FA IgG titer in the recovery stage showed a

Acute Viral Encephalitis/Encephalopathy in an Emergency Hospital in Japan: A Retrospective Study of 105 Cases...

HSE 2 1 1 2 2 1 0 0 3 2 14

JE 0 0 1 0 0 1 0 0 0 2 4

FluE 3 0 1 4 2 3 0 7 0 0 20

Mumps encephalitis 0 1 0 0 0 1 0 0 0 1 3

Rotavirus encephalopathy 0 0 0 0 0 0 0 1 0 0 1

NHALE, Anti-NMDARE 1 1 1 0 0 0 1 4 0 2 10

Viral-related ADEM 1 1 0 1 2 2 1 0 2 2 12

Viral encephalitis 4 7 10 3 3 5 0 2 1 1 36

Total 11 11 14 13 10 13 2 15 6 10 105

HSE=herpes simplex encephalitis, HHV-6=human herpesvirus-6, JE=Japanese encephalitis, FluE=influenza encephalop‐ athy, NHALE=non-herpetic limbic encephalitis, anti-NMDARE=anti--N-methyl-D-aspartate receptor encephalitis,

**Table 1.** Acute viral encephalitis/encephalopathy, St. Mary's Hospital, Kurume, Fukuoka, Japan, 2002 - 2011 (n=105)

Four cases of JE were recognized, with one case from September 2005, one from September 2007 and two from September and October 2011, respectively (Fig.4). The patients' ages and genders were 79 years/F, 93/F, 76/M, and 69/M, and the mean age was 79.3 years. One patient died one month after admission, and the other three patients suffered from severe sequelae. The 69-yearold man was found after having fallen in September 2011, and was admitted to our hospital. He was initially diagnosed as having had a stroke due to the onset of an acute right hemiparesis, but his CSF and MRI findings suggested JE, and the diagnosis was serologically confirmed by a sig‐ nificant increase in JE virus in the acute and convalescent sera. For all four JE cases, steroid pulse

**2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 Total**

http://dx.doi.org/10.5772/54605

45

0 0 0 3 1 0 0 1 0 0 5

high titer of 1280x for HHV-6.

H. zoster, HHV-6

encephalitis/encephalopathy

ADEM=acute disseminated encephalomyelitis

therapy was performed, but the effects were minimal.
