Disseminated Nocardia in an Immunocompetent Host

Abstract

A 44-year-old man with no medical comorbidities presented with recurrent inferior vena cava thrombosis and several months of fever, headache, and weight loss. Positron emission tomography–computed tomography was performed, which revealed a 1.5-cm fluorodeoxyglucose avid left lung mass and hypermetabolic soft tissue masses in bilateral inguinal regions (Figure 1). He underwent computed tomography–guided biopsy of the lung and left inguinal masses. Histopathology found clumps of filamentous branching bacilli, consistent with Nocardia (Supplemental Figure, available online at http://www.mayoclinicproceedings.org). Broad-range bacterial polymerase chain reaction (16s rRNA detection) returned positive for Nocardia paucivorans. Subsequent brain magnetic resonance imaging exhibited innumerable brain abscesses (Figure 2). Immunodeficiency work-up was performed and was unremarkable. He began therapy with intravenous trimethoprim-sulfamethoxazole, amikacin, and imipenem.Figure 2Abscesses with surrounding vasogenic edema on T2-weighted fluid-attenuated inversion recovery magnetic resonance imaging.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Nocardia is a filamentous, Gram-positive, partially acid-fast bacterium that is ubiquitous in the environment.1Lerner P.I. Nocardiosis.Clin Infect Dis. 1996; 22: 891-903Crossref PubMed Scopus (499) Google Scholar It is capable of disseminating to almost any organ, but it has a predilection for the lungs and brain. It also has a tendency to recur. Disseminated infection is more common in immunocompromised hosts, but approximately one-third of infections occur in patients who are immunocompetent.2Corti M.E. Villafañe-Fioti M.F. Nocardiosis: a review.Int J Infect Dis. 2003; 7: 243-250Abstract Full Text PDF PubMed Scopus (170) Google Scholar, 3Dominguez D.C. Antony S.J. Actinomyces and Nocardia infections in immunocompromised and nonimmunocompromised patients.J Natl Med Assoc. 1999; 91: 35-39PubMed Google Scholar, 4Sorrell T.C. Mitchell D.H. Iredell J.R. Chen S.C.-A. Nocardia species.in: Bennett J.E. Dolin R. Blaser M.J. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Elsevier, Philadelphia, PA2015: 2853-2863Crossref Scopus (16) Google Scholar Treatment for disseminated disease requires induction with intravenous multidrug therapy. Trimethoprim-sulfamethoxazole forms the backbone of induction therapy and is combined with one or both of amikacin and imipenem. Imipenem is required if there is central nervous system involvement. Treatment should be tailored based on susceptibilities, if available. After induction, patients may be transitioned to dual oral therapy with trimethoprim-sulfamethoxazole and either minocycline or amoxicillin-clavulanate. A total of 12 months of therapy is typical for immunocompromised patients and those with central nervous system involvement.4Sorrell T.C. Mitchell D.H. Iredell J.R. Chen S.C.-A. Nocardia species.in: Bennett J.E. Dolin R. Blaser M.J. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Elsevier, Philadelphia, PA2015: 2853-2863Crossref Scopus (16) Google Scholar We acknowledge and thank Julie Guerin, MD, and Ayse Tuba Kendi, MD, for interpreting and providing the images of the brain magnetic resonance imaging and positron emission tomography–computed tomography, respectively.