Listeria rhombencephalitis: report of two cases with early diagnosis and favourable outcome

Early trigeminal nerve involvement in Listeria monocytogenes rhombencephalitis: case series and systematic review

Listeria monocytogenes is associated with rhombencephalitis. However, the exact mechanisms of brainstem invasion remains poorly understood. Here, we demonstrate clinical and radiological data suggesting that Listeria may invade the brainstem via the trigeminal nerve. Three females (41, 64 and 70 years) with culture proven L. monocytogenes bacteremia and rhombencephalitis were investigated in the period of 2014-16. T2-weighted and contrast-enhanced T1-weighted MRI revealed a cerebellopontine abscess in all three patients, including the involvement of the trigeminal nerve root. In two patients, MRI also revealed selective contrast enhancement of the sensory trigeminal tract in the pons and medulla oblongata. Prior to any other neurological symptoms, two patients complained of hypoesthesia and a tingling sensation in the ipsilateral half of the face, consistent with sensory trigeminal nerve dysfunction on that side. In addition, we identified another 120 cases of Listeria rhombencephalitis following a systematic review. Cranial nerves VII, V, IX, and X, respectively, medulla oblongata, cerebellum and pons, were the most frequently involved brain structures. The present clinical and radiological findings corroborate earlier data from animal experiments, indicating that L. monocytogenes may be capable of retrograde intra-axonal migration along the cranial nerves. We suggest that in a subset of patients with rhombencephalitis L. monocytogenes enters the cerebellopontine angle through the trigeminal nerve, invading the brainstem via the sensory trigeminal nuclei.

Rhombencephalitis / brainstem encephalitis

Rhombencephalitis (RE) is a syndrome of multiple causes and multiple outcomes. Most authors now use the terms "rhombencephalitis" and "brainstem encephalitis" interchangeably even though anatomically they are slightly different. The etiologic categories of RE include infections, autoimmune diseases, and paraneoplastic syndromes (PNS). Listeria is the most common cause of infectious RE. Listeria RE primary occurs in healthy young adults. It usually occurs as a biphasic time course with a flu-like syndrome followed by brainstem dysfunction; 75% of patients have a cerebrospinal fluid (CSF) pleocytosis, and almost 100% have an abnormal brain MRI scan. Positive CSF and blood cultures are the most specific for diagnosis. Treatment primarily is with ampicillin. Enterovirus 71 is probably the second most common infectious cause of RE; however, 95% of cases have occurred in the Asian-Pacific region and there is no specific treatment. Herpes simplex virus (HSV) is the third most common infectious cause of RE, and about 80% of cases are caused by HSV1 and 20% by HSV2. About 50% only had involvement of the brainstem whereas the other 50% also had supratentorial involvement of the temporal and frontal lobes. Mortality with acyclovir treatment was 22% versus those not on acyclovir 75%. Epstein-Barr virus (EBV) and human herpesvirus 6 (HHV6) have caused a few cases. The most common autoimmune etiology is Behçet disease. Over 90% of those with Behçet RE had abnormal MRI scans and 94% had a CSF pleocytosis. Treatment is with corticosteroids and immunosuppressive agents, but only 25% have complete recovery. Paraneoplastic causes are the third category of RE. Brain MRIs are usually normal; there is usually a CSF pleocytosis but the protein is usually normal. Often anti-neuronal antibodies can be found. Prognosis is poor and treatment is only partially beneficial. Because Listeria and HSV are the most common treatable acute causes of RE, we recommend empiric therapy with ampicillin and acyclovir for all cases after samples have been obtained from CSF and blood for cultures and the polymerase chain reaction (PCR). Antibiotics can be changed based upon MRI, culture results, PCR results, and antibody studies.

A rare case of brainstem encephalitis by Listeria monocytogenes with isolated mesencephalic localization. Case report and review

We describe a case of brainstem infection by Listeria monocytogenes with right oculomotor palsy and lip drop, facial hypoesthesia, left arm paresthesia, positive blood culture, and sterile liquor in a 63-year-old man. Magnetic resonance imaging revealed an isolated mesencephalic lesion. Localization of this kind accounted for 3% of 111 cases reviewed.