title: Community-acquired meningitis in older adults: clinical features, etiology, and prognostic factors.
abstract: OBJECTIVE
  To investigate the epidemiology and outcomes of community-acquired meningitis in older adults.
  
  
  METHODS
  Retrospective study.
  
  
  METHODS
  Participants adults in Houston, Texas, with community-acquired meningitis hospitalized between January 1, 2005, and January 1, 2010 (N = 619; n = 54, 8.7%, aged ≥65; n = 565 aged <65).
  
  
  METHODS
  An adverse clinical outcome was defined as a Glasgow Outcome Scale score of 4 or less.
  
  
  RESULTS
  Older adults had higher rates of comorbidities, abnormal neurological and laboratory (serum white blood cell count >12,000/μL, and cerebrospinal fluid protein >100 mg/dL) findings (P < .001), abnormalities on computed tomography and magnetic resonance imaging of the head (P = .002), and adverse clinical outcomes (ACOs) (P < .001). The majority of participants (65.8%) had meningitis of unknown etiology. Bacterial meningitis was an infrequent cause of community-acquired meningitis (7.4%). Of the known causes, bacterial meningitis and West Nile virus were more common in older than younger adults; younger participants more frequently had cryptococcal and viral meningitis. On logistic regression, female sex was predictive of a poor outcome in the older participants (P = .002), whereas abnormal neurological examination (P < .001), fever (P = .01), and a cerebrospinal fluid glucose level less than 45 mg/dL (P = .002) were significant poor prognostic factors in younger participants.
  
  
  CONCLUSIONS
  Most cases of community-acquired meningitis are of unknown origin. Older adults are more likely than younger adults to have bacterial meningitis and West Nile virus infection when a cause can be identified. They also have more neurological abnormalities, laboratory and imaging abnormalities, and adverse clinical outcomes.
authors.affiliation: Department of Internal Medicine, University of Texas Health Science Center, Houston, Texas.
authors.forename: Amy Y
authors.initials: AY
authors.lastname: Wang
authors.forename: Jorge D
authors.initials: JD
authors.lastname: Machicado
authors.forename: Nabil T
authors.initials: NT
authors.lastname: Khoury
authors.forename: Susan H
authors.initials: SH
authors.lastname: Wootton
authors.forename: Lucrecia
authors.initials: L
authors.lastname: Salazar
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Hasbun
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology; D017714:Community-Acquired Infections / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D023261:Glasgow Outcome Scale; D005947:Glucose / Q000134:cerebrospinal fluid; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D016920:Meningitis, Bacterial / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D016919:Meningitis, Cryptococcal / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D008587:Meningitis, Viral / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D008875:Middle Aged; D009460:Neurologic Examination; D011379:Prognosis; D012189:Retrospective Studies; D012737:Sex Factors; D013781:Texas; D014057:Tomography, X-Ray Computed; D014901:West Nile Fever / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology; D055815:Young Adult
chemical_list: D005947:Glucose
keywords: community-acquired; meningitis; older adults