MR Imaging of BK virus encephalitis

Area of Science:

• Neurology
• Infectious Diseases
• Medical Imaging

Background:

• BK virus (BKV) is a polyomavirus typically associated with nephropathy in renal transplant recipients and hemorrhagic cystitis in bone marrow transplant recipients.
• Neurologic manifestations of BKV infection are rare, with encephalitis being an uncommon but serious complication.

Observation:

• A rare case of biopsy-confirmed BK virus encephalitis is presented in an immunocompromised patient.
• The patient also exhibited symptoms of hemorrhagic cystitis, a known urologic complication of BKV.

Findings:

• Magnetic Resonance (MR) imaging revealed widespread T2/fluid-attenuated inversion recovery (FLAIR) hyperintensities and restricted diffusion in the cerebellum, cerebral white matter, and deep gray matter.
• These dramatic imaging findings were observed despite the patient presenting with relatively mild clinical symptoms.

Implications:

• The simultaneous occurrence of urologic abnormalities and neurological deficits in immunocompromised patients warrants consideration for BKV encephalitis.
• This case underscores the importance of neuroimaging in diagnosing rare BKV-related neurological complications.
• Early recognition and diagnosis are crucial for managing BKV encephalitis in at-risk populations.