Influenza B-induced longitudinally extensive transverse myelitis and bithalamic acute disseminated encephalomyelitis

In the COVID-era, other viral pathogens, like influenza B, gain less attention in scientific reporting. However, influenza still is endemic, and rarely affects central nervous system (CNS). Here, we report the case of a 35-year-old male who presented with fever since 1 week, and developed acute ascending flaccid paralysis and urinary retention. The clinical presentation of paraparesis in combination with the inflammation proven by the lumbar puncture, and the MRI full spine, fulfilled the diagnostic criteria of longitudinally extensive transverse myelitis (LETM). In this case, it is most likely based on a post-viral Influenza type B. Additionally, the brain MRI showed a necrotizing encephalopathy bilaterally in the thalamus. Both locations of inflammatory disease were part of one auto-immune-mediated, monophasic CNS disorder: influenza-induced ADEM which is very unique, fortunately with favorable outcome.