Listeria rhombencephalitis
General description
Listeria monocytogenes, a gram-positive rod-shaped bacterium, is recognized as a causative agent of bacterial meningitis. This bacterium predominantly affects newborns, the elderly, and immunocompromised patients. Infections can sometimes occur as part of a widespread endemic, transmitted through contaminated foods.
In cases of Listeria infection, the brainstem is frequently involved, including in immunocompetent individuals. Besides the brainstem, the cerebrum and cerebellum may also be affected.
Abscess formation
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Cerebellum
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Brainstem
Listeria infection is an important differential diagnosis in immune competent patients. It is supposed that the listeria infection spreads retrospectively through nasopharynx.
On T2WI , there is central hyperintensity with peripheral low intensity observed. DWI shows homogeneous hyperintensity in the abscess.
Microabscess
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Cerebellum
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Brainstem
In Listeria encephalitis, the brainstem often does not show obvious space-occupying abscesses but is instead typically characterized by high signal changes on T2WI and FLAIR sequences.
Neural degeneration
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CerebrumCerebral white matter
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Internal capsule
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Cerebral peduncle
In Listeria encephalitis, degeneration of nerves along the path of neural innervation originating from the lesion site can often be observed. Typically, this involves the cerebral peduncles and the internal capsule, leading to increased signal intensity along the white matter tracts of the cerebrum on T2WI and FLAIR sequences.