[Listeria rhombencephalitis. Neuroradiological findings]

Rhombencephalitis due to listeria monocytogenes is an uncommon and serious form of brainstem infection. The disease has a characteristic biphasic course: a nonspecific prodrome of headache, nausea or vomiting, and fever lasting for a several days is followed by progressive asymmetrical cranial-nerve palsies. We report two cases of Listeria monocytogenes rhombencephalitis. The first case is a previously healthy 20 year-old-man who developed fever, headache, nausea and vomiting, followed by numbness in left trigeminal nerve. The second case is an immunosuppressed 77 year-old-man, who developed sudden left hemiparesis, followed by fever and severe brainstem dysfunction with ophthalmoplegia and dysphagia. In both cases, a brain magnetic resonance imaging (MRI) scan, showed increased intensity on T2-weighted lesions in the brainstem that enhanced after contrast on T1-weighted sequences. Both patients had a favorable outcome with full clinical recovery. We conclude that MRI aids in the early detection of parenchymal infections, therefore, MRI is crucial for early diagnosis and is very useful for follow-up examinations.