International outbreaks of listerial infections have become more frequent in recent years. Listeria monocytogenes, which usually contaminates food, can cause potentially fatal infections. Listerial cerebritis is a rare disease that is encountered mostly in immunocompromised or elderly patients. However, listerial brainstem encephalitis (mesenrhombencephalitis or rhombencephalitis) is found in persons who were formerly in good health, and recognizing this disease, particularly at its early stages, is challenging. Listerial brainstem encephalitis has high mortality, and serious sequelae are frequently reported in survivors. Early recognition and correct diagnosis, as well as the timely use of appropriate antibiotics, can reduce the severity of listerial infections. The trigeminal nerve is proposed as a pathway through which L. monocytogenes reaches the brainstem after entering damaged oropharyngeal mucosa or periodontal tissues. This review introduces the clinical manifestations, pathology, magnetic resonance imaging (MRI) findings, diagnosis, and treatment of listerial brainstem encephalitis. Moreover, it proposes that L. monocytogenes may also invade the brainstem along the vagus nerve after it infects enteric neurons in the walls of the gastrointestinal tract.
Keywords: Listeria monocytogenes; MRI; brainstem encephalitis; vagus nerve.