title: Intracranial abscess due to Mycobacterium avium complex in an immunocompetent host: a case report.
abstract: BACKGROUND
  Mycobacterium avium complex (MAC) is a ubiquitous pathogen, widely distributed in the environment including water, soil and animals. It is an uncommonly encountered clinical pathogen; primarily causing pulmonary infections in patients with underlying lung disease or disseminated disease in immunocompromised hosts. Sporadically, extra-pulmonary infections have been documented including involvement of the liver, spleen, skin, soft tissue and lymph nodes. Central nervous system (CNS) infections due to MAC are exceedingly rare and carry a poor prognosis. Additionally, such infections are largely reported in patients infected with HIV. Herein we report the first case of intracranial abscess due to MAC in an immunocompetent man with a normal CD4 count and negative HIV status.
  
  
  METHODS
  A previously healthy 40-year-old male presented to us with progressively worsening CNS symptoms. The patient's presentation was uncharacteristic of MAC infection in immunocompetent hosts, as he developed subacute, progressive symptoms that included severe frontal headaches, left eyelid swelling, blurry vision, and diplopia, without any pulmonary or systemic manifestations. Neuroimaging revealed multiple ring-enhancing lesions, which required neurosurgical intervention. MAC was the only pathogen that grew from intraoperative tissue cultures. The patient was subsequently treated with a 12-month regimen consisting of Clarithromycin, Ethambutol, and Rifampin, with successful clinical resolution.
  
  
  CONCLUSIONS
  Our findings indicate that it is important to consider rare infections such as MAC in immunocompetent patients, regardless of atypical symptoms. Despite the severity of this infection, with timely diagnosis effective treatment is available.
authors.affiliation: Department of Internal Medicine, Mercer University School of Medicine, 707 Pine Street, Macon, GA, 31201, USA. mu.chowdhary@gmail.com.
authors.forename: Mudit
authors.initials: M
authors.lastname: Chowdhary
authors.affiliation: Department of Pediatrics, Mercer University School of Medicine, Macon, GA, USA. narsinghani.umesh@navicenthealth.org.
authors.forename: Umesh
authors.initials: U
authors.lastname: Narsinghani
authors.affiliation: Department of Internal Medicine, Mercer University School of Medicine, 707 Pine Street, Macon, GA, 31201, USA. kumar_ra@mercer.edu.|Department of Infectious Diseases, Mercer University School of Medicine, Macon, GA, USA. kumar_ra@mercer.edu.
authors.forename: Ritu A
authors.initials: RA
authors.lastname: Kumar
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D001922:Brain Abscess / Q000175:diagnosis* / Q000188:drug therapy; D017291:Clarithromycin / Q000627:therapeutic use; D003937:Diagnosis, Differential; D004359:Drug Therapy, Combination; D004977:Ethambutol / Q000627:therapeutic use; D006801:Humans; D008297:Male; D015269:Mycobacterium avium Complex / Q000302:isolation & purification*; D015270:Mycobacterium avium-intracellulare Infection / Q000175:diagnosis* / Q000188:drug therapy; D012293:Rifampin / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D004977:Ethambutol; D017291:Clarithromycin; D012293:Rifampin