Severe invasive Listeria monocytogenes rhombencephalitis mimicking facial neuritis in a healthy middle-aged man: a case report and literature review

Abstract

Neurolisteriosis is a foodborne infection of the central nervous system that is easily misdiagnosed, especially in healthy adults with atypical symptoms. A 50-year-old man presented with a 3-day history of distortion of the oral commissure. Facial neuritis was diagnosed and treated with intravenous dexamethasone. His condition deteriorated rapidly, and he presented with a slow pharyngeal reflex, stiff neck, and signs of peripheral facial paralysis. Brain magnetic resonance imaging revealed multiple ring-enhanced foci in the brainstem. Routine and biochemical cerebrospinal fluid (CSF) analyses showed increased white blood cells and microproteins. Blood culture and high-throughput genome sequencing revealed Listeria monocytogenes DNA in the CSF. Ampicillin, amikacin, and meropenem were administered, and the patient was transferred from the intensive care unit to a standard medical ward after 2 months. The patient could walk and eat normally; however, he required intermittent mechanical ventilation at 11 months after discharge. Although L. monocytogenes meningitis is rare in healthy immunocompetent adults, it must be considered as a differential diagnosis, especially in adults whose conditions do not improve with cephalosporin antibiotic administration. L. monocytogenes rhombencephalitis mimics facial neuritis and develops quickly. Prompt diagnosis is essential for rapid initiation of antibiotic therapy to achieve the best outcome.

Keywords: Bell’s palsy; Listeria monocytogenes; case report; facial paralysis; meningoencephalitis; neurolisteriosis.

Figure 1.

Computed tomography (CT), magnetic resonance imaging (MRI), and blood culture results. (a) Head CT showing no apparent abnormality after admission. (b) The patient’s condition worsened; however, head CT re-examination showed no apparent abnormality on the third day after admission. (c) T1-weighted image (WI) showing low-signal midbrain lesions (arrow). (d) T2-WI showing a hyperintense dorsal pontine lesion (arrow). (e) Diffusion WI showing no abnormal signal in the midbrain. (f) A high apparent diffusion coefficient was observed in the midbrain lesions (arrow). (g) Fluid-attenuated inversion recovery sequence showing hyperintense lesions (arrow) in the dorsal lower pons. (h–k) Gadolinium-enhanced MRI showing multiple ring-enhanced lesions in the (h) left midbrain (arrow), (i) medulla oblongata, (j) dorsal upper medulla oblongata (arrow), and (k) dorsal lower pons (arrow). (l) Listeria monocytogenes was cultured from peripheral blood. The tryptone soy blood agar plate produced round bacterial colonies with neat edges and central uplifting; the surfaces were smooth and whitish gray.