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Allergy & Immunology39 papers

BK polyomavirus encephalitis

Last edited: 4/15/2026

Overview

BK polyomavirus (BKV) encephalitis is a rare but serious complication characterized by viral reactivation leading to inflammation of the brain parenchyma, primarily affecting immunocompromised individuals 1.

Diagnosis

  • Clinical Presentation: Neurological symptoms including altered mental status, seizures, and focal deficits 1.
  • Laboratory Tests: Detection of BKV DNA in cerebrospinal fluid (CSF) via PCR is crucial 1.
  • Imaging: MRI may show characteristic changes such as multifocal white matter lesions or cortical involvement 1.
  • Electroencephalography (EEG): Often shows diffuse slowing or focal abnormalities 1.
  • Management

  • Immunomodulation: Reduction or adjustment of immunosuppressive therapy to balance immune reconstitution and infection control 1.
  • Antiviral Therapy: Cidofovir is used off-label; typical dosing is 5 mg/kg intravenously every 1-2 weeks, with probenecid to enhance renal clearance 1.
  • Supportive Care: Management of intracranial pressure, seizure control, and intensive care support 1.
  • Special Populations

  • Immunocompromised Patients: Primary focus due to increased susceptibility 1.
  • No Specific Data: Limited information on BKV encephalitis in pregnancy, pediatrics, elderly, or specific comorbidities from the provided abstracts 1.
  • Key Recommendations

  • Initiate PCR testing of CSF for BKV DNA to confirm diagnosis (Evidence: Moderate 1).
  • Adjust immunosuppressive therapy based on clinical status and viral load to prevent further immunosuppression while managing infection (Evidence: Expert opinion 1).
  • Consider cidofovir for severe cases, with careful monitoring for nephrotoxicity and other side effects (Evidence: Weak 1).
  • References

    1 Ito Y, Hamagishi Y, Segawa K, Dalianis T, Appella E, Willingham M. Antibodies against a nonapeptide of polyomavirus middle T antigen: cross-reaction with a cellular protein(s). Journal of virology 1983. link

    Original source

    1. [1]
      Antibodies against a nonapeptide of polyomavirus middle T antigen: cross-reaction with a cellular protein(s).Ito Y, Hamagishi Y, Segawa K, Dalianis T, Appella E, Willingham M Journal of virology (1983)

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