title: Respiratory syncytial virus-related encephalitis: magnetic resonance imaging findings with diffusion-weighted study.
abstract: BACKGROUND
  Respiratory syncytial virus (RSV) is a common pathogen causing acute respiratory infection in children. Herein, we describe the incidence and clinical and magnetic resonance imaging (MRI) findings of RSV-related encephalitis, a major neurological complication of RSV infection.
  
  
  METHODS
  We retrospectively reviewed the medical records and imaging findings of the patients over the past 7 years who are admitted to our medical center and are tested positive for RSV-RNA by reverse transcriptase PCR. In total, 3,856 patients were diagnosed with RSV bronchiolitis, and 28 of them underwent brain MRI for the evaluation of neurologic symptoms; 8 of these 28 patients had positive imaging findings. Five of these 8 patients were excluded because of non-RSV-related pathologies, such as subdural hemorrhage, brain volume loss due to status epilepticus, periventricular leukomalacia, preexisting ventriculomegaly, and hypoxic brain injury.
  
  
  RESULTS
  The incidence of RSV-related encephalitis was as follows: 3/3,856 (0.08 %) of the patients are positive for RSV RNA, 3/28 (10.7 %) of the patient underwent brain MRI for neurological symptom, and 3/8 (37.5 %) of patients revealed abnormal MR findings. The imaging findings were suggestive of patterns of rhombenmesencephalitis, encephalitis with acute disseminated encephalomyelitis, and limbic encephalitis. They demonstrated no diffusion abnormality on diffusion-weighted image and symptom improvement on the follow-up study.
  
  
  CONCLUSIONS
  Encephalitis with RSV bronchiolitis occurs rarely. However, on brain MRI performed upon suspicion of neurologic involvement, RSV encephalitis is not infrequently observed among the abnormal MR findings and may mimic other viral and limbic encephalitis. Physicians should be aware of this entity to ensure proper diagnosis and neurologic care of RSV-positive patients.
authors: Department of Radiology, Korea University Guro Hospital, Korea University College of Medicine, 97 Gurodong, Guro-gu, Seoul, 172-703, Korea.
authors: Arim
authors: A
authors: Park
authors: Sang-il
authors: SI
authors: Suh
authors: Gyu-Ri
authors: GR
authors: Son
authors: Young Hen
authors: YH
authors: Lee
authors: Hyung Suk
authors: HS
authors: Seo
authors: Baik-Lin
authors: BL
authors: Eun
authors: Nam-Joon
authors: NJ
authors: Lee
authors: Hae-Young
authors: HY
authors: Seol
mesh_terms: D001921:Brain / Q000473:pathology*; D002675:Child, Preschool; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D018792:Encephalitis, Viral / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D018357:Respiratory Syncytial Virus Infections / Q000175:diagnosis* / Q000453:epidemiology*; D018570:Risk Assessment; D012307:Risk Factors