Delayed onset of post-rabies vaccination encephalitis

Area of Science:

• Neurology
• Immunology
• Vaccinology

Background:

• Rabies vaccination is crucial for preventing a fatal viral disease.
• Adverse neurological events following vaccination are rare but documented.
• Understanding vaccine-induced neurological complications is vital for patient safety.

Observation:

• A 31-year-old veterinarian presented with seizures, left hemiparesis, memory loss, and behavioral changes.
• Symptoms appeared 5 months post-intensive antirabies vaccination, a notably long incubation period.
• Neuroimaging revealed a contrast-enhancing frontal lobe mass with callosal extension.

Findings:

• Brain biopsy confirmed primary demyelination predominantly in white matter.
• The observed lesions were characteristic of demyelinating encephalomyelitis associated with certain rabies vaccines.
• While hemiplegia showed improvement, persistent seizures and cognitive deficits were noted.

Implications:

• This case underscores the possibility of delayed-onset demyelinating encephalomyelitis after rabies vaccination.
• The extended incubation period challenges typical timelines for vaccine-related adverse events.
• Further research into the immunopathogenesis of vaccine-induced demyelination is warranted.