title: Human herpesvirus-6 infection-associated acute encephalopathy without skin rash.
abstract: BACKGROUND
  Human herpesvirus-6 (HHV-6) is the etiological agent of exanthema subitum-associated encephalopathy, which usually occurs in children younger than 3 years. Brain imaging shows various abnormalities.
  
  
  METHODS
  A previously healthy 4-year-old girl developed acute encephalopathy with clinical features consisting of fever, repetitive seizures, and a disturbance of consciousness. The patient did not show skin rash suggestive of exanthema subitum during the course of her illness. The primary HHV-6 infection was diagnosed based on the absence of IgG against HHV-6 and identification of the virus DNA in the acute phase serum and a significant increase of the anti-HHV-6 IgG titers in the convalescent phase sera. Diffusion-weighted images showed transient high signal intensity in the bilateral periventricular white matter and splenium of the corpus callosum and in the gray matter structures such as the bilateral basal ganglia and thalami. Upon therapy with steroid and γ-globulin, the patient recovered without any neurological deficits.
  
  
  CONCLUSIONS
  Primary HHV-6 infection can cause acute encephalopathy without exanthema subitum. The etiological diagnosis is possible only by examining the blood and cerebrospinal fluid, when the patient shows no skin rash. This condition should be included in the differential diagnosis of acute encephalopathy even in patients older than 3 years.
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa 078-8510, Japan.
authors.forename: Shiho
authors.initials: S
authors.lastname: Yamamoto
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa 078-8510, Japan. Electronic address: satoru5p@asahikawa-med.ac.jp.
authors.forename: Satoru
authors.initials: S
authors.lastname: Takahashi
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa 078-8510, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Tanaka
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa 078-8510, Japan.
authors.forename: Akie
authors.initials: A
authors.lastname: Okayama
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa 078-8510, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Araki
authors.affiliation: Department of Pathology, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
authors.forename: Harutaka
authors.initials: H
authors.lastname: Katano
authors.affiliation: Infectious Disease Surveillance Center, National Institute of Infectious Diseases, Tokyo 162-8640, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Tanaka-Taya
authors.affiliation: Department of Pediatrics, Asahikawa Medical University, Asahikawa 078-8510, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Azuma
mesh_terms: D001927:Brain Diseases / Q000821:virology*; D002675:Child, Preschool; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D018792:Encephalitis, Viral / Q000097:blood / Q000473:pathology* / Q000821:virology*; D005076:Exanthema / Q000821:virology; D005260:Female; D015654:Herpesvirus 6, Human / Q000302:isolation & purification*; D006801:Humans; D019349:Roseolovirus Infections / Q000097:blood / Q000473:pathology* / Q000821:virology*; D012640:Seizures / Q000821:virology
keywords: Diffusion-weighted imaging; Encephalitis; Encephalopathy; Exanthema subitum; Human herpesvirus-6; Magnetic resonance imaging; Periventricular white matter