704 - Listeria rhombencephalitis and abscess in an immunocompromised patient

Case Diagnosis: Listeria Rhombencephalitis

Case Description: An 80-year-old female with diabetes mellitus type 2, hypertension, monoclonal gammopathy of undetermined significance presented to the emergency department with altered mental status, lethargy, headache, nausea, vomiting, and right facial droop. The patient was placed on prophylactic antibiotics for possible encephalitis. Imaging of the head showed abnormal enhancement in the right brainstem and right middle cerebellar peduncle compatible with listeria rhombencephalitis and small brain abscess formation. Prior to hospitalization, the patient was independent with ADLs. Patient was discharged to acute inpatient rehabilitation to address functional deficits secondary to right lower and left upper extremity weakness, and dysphagia requiring percutaneous endoscopic gastrostomy tube.

Discussions: Listeria is a facultative intracellular parasite present in the soil and decaying vegetable matter. It is transmitted via oral ingestion. Individuals most at risk for infection include neonates, pregnant women, immunocompromised and older individuals. Clinical manifestations of listeria infections include febrile gastroenteritis, bacteremia and central nervous system (CNS) infection. CNS infection manifestations can range from mild illness with fever and altered mental status, to coma. The most common CNS manifestation is meningoencephalitis that may be either generalized or with focal involvement to the brainstem (rhombencephalitis). Rhombencephalitis is a relatively uncommon manifestation and progression to frank brain abscess is an uncommon complication. Neurological sequelae are an anticipated with listeria CNS infection and can include seizures, hemiparesis, and ataxia. The patient was treated with a combination of ampicillin and Bactrim.

Conclusions: Rhombencephalitis is an uncommon complication of a listeria infection. Older individuals who are immunocompromised are at increased risk for acquiring CNS infection. This case demonstrates the debilitating risk these immunosuppressed individuals carry when exposed to the foodborne pathogen.