Background: Listeriosis is a known cause of community acquired bacterial meningitis/meningoencephalitis. It occurs more frequently in neonates, older people and immunocompromised hosts. Rarely, brain abscesses can complicate the course of infection, which poses a difficulty in the management and elevates morbidity and mortality. Myasthenia gravis is an autoimmune disease that often requires immunosuppressive treatment, which increases the risk for invasive infections.
Case description: A 75-year-old myasthenic patient, treated with prednisone and pyridostigmine, was diagnosed with invasive listeriosis. He presented with muscle weakness, dyspnea, hemiparesis and altered mental status. Brain imaging revealed multiple abscesses and blood cultures were positive for Listeria monocytogenes. Despite combination antibiotic therapy, he died 6 weeks after admission.
Systematic review: Ninety-six cases of brain abscesses from 1968 to 2023 were reviewed; the majority of the patients were men, 54 years-old on average, and had at least one risk factor for invasive listeriosis. The mortality exceeded 22%. Blood cultures and CSF/abscess cultures were positive in only 79.2% and 54.6%, respectively. The most common therapeutic approach was a combination regimen that included amoxicillin or ampicillin. Only 8 patients underwent surgery, of which one died.
Conclusion: This case highlights the importance of L. monocytogenes as a cause of brain abscesses in populations at risk, including myasthenic patients. The challenge of diagnosing and treating this condition is aggravated by the paucity of literature and the high mortality rate.
Keywords: Listeria monocytogenes; Listeriosis; brain abscess; meningoencephalitis; myasthenia gravis.