title: BK virus encephalitis in an immunocompetent patient.
abstract: OBJECTIVE
  To describe a previously healthy patient now suffering from monophasic encephalitis caused by a primary infection with BK virus and to discuss possible risk factors for developing BK virus encephalitis.
  
  
  METHODS
  Case report.
  
  
  METHODS
  Referral hospital.
  
  
  METHODS
  The patient was examined on referral.
  
  
  METHODS
  The main diagnostic tests performed were serology, polymerase chain reaction on cerebrospinal fluid samples, and cranial magnetic resonance imaging.
  
  
  RESULTS
  During the course of the patient's encephalitis, an IgM titer developed against polyomavirus, followed by anti-polyomavirus IgG. Wild-type BK virus was demonstrated in cerebrospinal fluid samples. Cranial magnetic resonance imaging showed diffuse reversible white matter changes most prominent on T2-weighted images.
  
  
  CONCLUSIONS
  We conclude that diagnostic tests for BK, a human polyomavirus, should be included in the screening program for encephalitogenic pathogens.
authors.affiliation: Department of Neurology, Klinikum Grosshadern, Munich, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Voltz
authors.forename: G
authors.initials: G
authors.lastname: Jäger
authors.forename: K
authors.initials: K
authors.lastname: Seelos
authors.forename: L
authors.initials: L
authors.lastname: Fuhry
authors.forename: R
authors.initials: R
authors.lastname: Hohlfeld
mesh_terms: D000328:Adult; D001739:BK Virus; D001921:Brain / Q000473:pathology; D002555:Cerebrospinal Fluid / Q000821:virology; D018792:Encephalitis, Viral / Q000175:diagnosis / Q000821:virology*; D006801:Humans; D007121:Immunocompetence; D008297:Male; D016133:Polymerase Chain Reaction; D027601:Polyomavirus Infections / Q000175:diagnosis; D012698:Serologic Tests; D014412:Tumor Virus Infections / Q000175:diagnosis