Listeria monocytogenes meningitis

Listeria monocytogenes-related central nervous system infections may involve the cerebral parenchyma. Meningitis and meningoencephalitis are the most commonly seen forms and mainly affect immunocompromised patients; however, a less frequent form, rhombencephalitis, can occur in otherwise healthy people. Early treatment with appropriate antibiotic therapy is crucial for this otherwise fatal disorder. However, it is not always possible to rapidly establish the diagnosis because of varying presentations and discrepancies in diagnostic tests.

Diker et al., report 3 cases of listerial infections involving the central nervous system parenchyma, with versatile diagnostic challenges and related possible solutions and radiologic hints to overcome similar issues in the future.

They point out the importance of nonconventional magnetic resonance imaging techniques in the diagnosis, as they detected petechial hemorrhages in the brain parenchyma in all cases, which can be a diagnostic clue ¹⁾.

Paediatric Listeria monocytogenes bacterial meningitis is rare, especially in immuno-competent children, but associated with significant mortality and morbidity and frequent complications.

Patients with L. monocytogenes meningitis rarely develop the complication of symptomatic hydrocephalus.

3 previously healthy Costa Rican children who had Listeria monocytogenes meningitis, . Two of them had initial normal brain computed tomography, but all 3 developed acute hydrocephalus at days 7, 3, and 5, respectively. All required immediate ventriculostomy placement and only 1 of 3 survived. L. monocytogenes should be considered among the etiologies of bacterial meningitis in children who do not respond initially to conventional antimicrobial treatment or who deteriorate rapidly ²⁾.

A previously healthy 35 month-old girl with selective spinal grey matter involvement and demyelination in neurophysiological studies. Despite adequate antibiotic treatment, the case was initially complicated by ventriculitis, hydrocephalus and tonsillar herniation through the foramen magnum, requiring external ventricular drainage and subsequent ventriculoperitoneal shunt insertion. Paucity of movements, hypotonia, areflexia and bladder dysfunction then became evident.

Electromyogram and nerve conduction studies showed acute inflammatory demyelinating polyneuropathy and the patient received intravenous immunoglobulin followed by corticosteroids. MRI scans with contrast revealed extensive whole cord selective grey matter signal changes. She required extensive neurorehabilitation, making gradual (but incomplete) recovery.

Spinal cord involvement is rare in neuro-listeriosis and there no previous paediatric reports of Listeria-related myelitis or demyelinating polyneuropathy. The mechanism behind these presentations is unclear but an auto-immune response to the infection might be considered ³⁾.

Yang et al report a patient with L. monocytogenes meningitis who presented with persistent alteration of consciousness after appropriate antimicrobial therapy. Follow-up brain computed tomography revealed acute hydrocephalus. An Ommaya reservoir was implanted, and daily drainage of the cerebrospinal fluid was performed. The patient improved gradually and his mental status recovered completely 4 days later. This case should remind physicians to be aware of the possible occurrence of hydrocephalus in L. monocytogenes meningitis and that prompt cerebrospinal fluid drainage may achieve a good outcome ⁴⁾.

A case of rhombencephalitis with meningitis in a 36-years-old previously healthy man; neurological signs and symptoms were initially consistent with a diagnosis of Wallenberg syndrome. Analysis of cerebrospinal fluid showed predominantly lymphocytic pleocytosis and elevated protein levels. A CT brain scan was normal. MRI of the brain showed a hypertensive type lesion in T2, in the right pontomedullary region that suggested inflammation. A blood culture grew Listeria monocytogenes. The patient improved and fully recovered with appropriate antibiotic treatment. Listeria monocytogenes is a recognized cause of acute brainstem meningoencephalitis. Differential diagnoses that must be considered are other forms of purulent meningitis, viral meningoencephalitis, granulomatosis infections of the central nervous system and, occasionally, stroke ⁵⁾.