LISTERIA BACTEREMIA PRESENTING WITH CEREBRAL ABSCESS AND ENDOCARDITIS IN AN ELDERLY PATIENT WITH CHRONIC IMMUNE THROMBOCYTOPENIA

Abstract

TOPIC: Cardiovascular Disease TYPE: Medical Student/Resident Case Reports INTRODUCTION: Listeria monocytogenes, an intracellular gram-positive bacillus, is a ubiquitous foodborne pathogen that causes Listeriosis. Its clinical spectrum ranges from mild, self-limiting gastroenteritis in immunocompetent individuals to severe, life-threatening, invasive disease affecting persons at the extremes of age, pregnant women, and individuals with cell-mediated immunodeficiencies. Central nervous system involvement by is common – presenting as meningitis, meningoencephalitis or, less frequently, rhombencephalitis. Listerial brain abscesses are rare. Moreover, only 5-8% of these infections are complicated by infective endocarditis (IE). CASE PRESENTATION: A 70-year-old Caucasian man with chronic immune thrombocytopenia (ITP) presented to the ED with acute onset of altered mental status and right-sided weakness. He was afebrile, with no heart murmurs or peripheral stigmata of IE. Neurologic exam findings included disorientation, expressive aphasia, and right-sided hemiparesis. Laboratory findings were unremarkable except for leukocytosis and hyponatremia. Brain MRI showed an irregular rim-enhancing lesion in the left frontal lobe with surrounding edema and midline shift. The lesion was excised with adjacent necrotic tissue and frozen sections were highly suspicious for a high-grade glial neoplasm. He was started empirically on vancomycin, ceftriaxone and metronidazole. Eventually, the organism was identified as Listeria monocytogenes from two sets of blood cultures; hence, antibiotics were de-escalated to ampicillin and gentamicin. Transesophageal echocardiography (TEE) showed mitral valve vegetation. The patient developed fever on day 4; by day 6, he began to defervesce and showed improvement in mental status. On day 9, he was discharged to the inpatient rehabilitation center to complete a total of 6 weeks on IV ampicillin and IV gentamicin. Pathology of the brain mass was subsequently reported as listerial brain abscess with no evidence of malignancy. DISCUSSION: Chronic treatment with high-dose oral glucocorticoids and pre-existing ITP have been independently implicated as predisposing factors in listerial brain abscess. There is a propensity to misdiagnose listerial brain abscess as an intracranial neoplasm due to similar clinical/imaging findings, especially when fever is absent at presentation. In addition, Listeria monocytogenes is an atypical cause of IE. Our patient had no pre-existing structural or valvular heart disease, but he satisfied two major diagnostic criteria for IE – two separate positive blood cultures of Listeria monocytogenes and a TEE demonstrating mitral valve vegetation. CONCLUSIONS: A high index of suspicion is necessary for early recognition and successful treatment of listerial brain abscess and listerial endocarditis in high-risk patients. REFERENCE #1: Tiri B, Priante G, Saraca LM, Martella LA, Cappanera S, Francisci D. Listeria monocytogenes brain abscess: controversial issues for the treatment—two cases and literature review. Case Rep Infect Dis. 2018;2018(6549496):1-9. REFERENCE #2: Hohmann EL, Portnoy DA. Listeria monocytogenes infections. In: Jameson JL, Kasper DL, Longo DL, Fauci AS, Hauser SL, Loscalzo J, eds. Harrison's Principles of Internal Medicine. 20th ed. New York, NY: McGraw-Hill Education; 2018:1100-1102. REFERENCE #3: Garcia-Granja PE, Lopez J, Vilacosta I, Olmos C, Sarria C, Roman JAS. Infective endocarditis due to Listeria monocytogenes: a report of 4 patients. Cardiol. 2016;69(7):699–709. DISCLOSURES: No relevant relationships by Nili Gujadhur, source=Web Response no disclosure on file for Vanessa Karimi; No relevant relationships by Olushola Ogunleye, source=Web Response