Introduction: Central nervous system infections caused by Listeria monocytogenes usually manifest in the form of meningitis or meningoencephalitis, and are more common among immunosuppressed patients. Brainstem encephalitis (rhombencephalitis) is less common and fatal if not recognized and treated early.
Case report: We describe the case of a 40-year-old, immunocompetent male patient, who presented with initial symptoms of high fever and productive cough. Signs of brainstem involvement appeared later. A magnetic resonance imaging of the brain revealed a lesion of inflammatory appearance in the right medulla oblongata, and the cerebrospinal fluid test showed mononuclear pleocytosis. Blood and cerebrospinal fluid cultures were negative. He presented with a significant improvement with the start of ceftriaxone and subsequent association of corticosteroids, until he developed respiratory failure and died. The third blood cultures grew after his death and they were positive for L. monocytogenes. An autopsy was carried out, which showed necrotizing inflammation, with gram-positive bacilli in the brainstem and the cerebellum.
Conclusions: A fatal delay in the diagnosis occurred, mainly because of the favorable clinical response to ceftriaxone and corticosteroids. This case reminds us that a febrile clinical presentation with brainstem involvement must generate the suspicion of a Listeria infection, and therefore ampicillin must be a part of the empirical treatment.