All the More Reason to Get a Flu Shot: An Instance of Acute Hemorrhagic Leukoencephalitis in a Patient With Influenza A

Acute hemorrhagic leukoencephalitis (AHLE) is a rare demyelinating disease of the central nervous system that typically follows a viral or bacterial respiratory infection. We report the first described case of AHLE following influenza A (H3N2) in an otherwise healthy 15-year-old girl with no relevant past medical history who initially presented to the emergency department (ED) by emergency medical services (EMS) with decorticate posturing and right gaze deviation after being found unresponsive at home. Subsequent testing for Influenza A H3N2 via viral polymerase chain reaction (PCR) was positive. Clinical correlation and brain MRI confirmed AHLE. At follow-up three months after discharge, she was found to have intellectual functioning in the extremely low range and she still had deficits in motor skills eight months after discharge. While the patient was reportedly up-to-date on her routine scheduled childhood vaccinations, she had not received her annual influenza vaccination that year. Pediatric infectious disease physicians and neurologists should consider the diagnosis of AHLE in unvaccinated, previously healthy patients with new and rapid onset of neurological symptoms following influenza infection.