From the Research
Listeria monocytogenes encephalitis typically presents with distinctive radiographic findings on brain imaging, including rhombencephalitis, which shows abnormal signal intensity or enhancement in the brainstem, particularly the pons and medulla, as well as the cerebellum on MRI, as reported in the most recent study 1. The key radiographic findings of listeria encephalitis include:
- T2 hyperintensity and contrast enhancement in the brainstem and cerebellum, as seen in 80% and 60% of patients, respectively 2
- Ring-enhancing lesions, which are considered as brain abscess, found in 46% of patients 2
- Multiple small abscesses throughout the brain parenchyma, which may appear as ring-enhancing lesions with surrounding edema
- Meningeal enhancement, reflecting the meningitic component of the infection
- Hydrocephalus, which may develop as a complication These findings reflect Listeria's predilection for the brainstem and cerebellum, which distinguishes it from many other bacterial causes of encephalitis, as noted in a study published in 2020 3. The radiological features of neurolisteriosis have been thoroughly studied, and the most common findings include meningeal enhancement, abscesses or nodular images, hemorrhages, and white-matter images, as reported in a prospective study of 71 cases 4. Early recognition of these radiographic patterns is crucial for prompt initiation of appropriate antibiotic therapy, typically ampicillin with or without gentamicin, as the prognosis is poor if left untreated, with a mortality rate of 20% and neurological sequelae in 68% of patients 2.