This document provides information about community acquired bacterial meningitis in adults. It discusses the changing epidemiology, pathogens, pathogenesis, diagnosis, and treatment guidelines. The key points are: 1) Since the introduction of vaccines for H. influenzae and S. pneumoniae, there has been a 90% reduction in H. influenzae infections and the median age of meningitis cases has increased to 39 years old. 2) Common pathogens include S. pneumoniae, N. meningitidis, Listeria monocytogenes, and gram-negative bacilli. Mortality is highest in those over 65. 3) Treatment guidelines recommend dexamethasone be administered with the first dose of antibiotics to

1. COMMUNITY ACQUIRED
BACTERIAL MENINGITIS
IN ADULTS
Julie Hoffman, M.D.
Department of ID
Jacobi Medical Center

2. Acute Meningitis
 Meningitis-inflammation of the meninges, identified by
abnormal WBCs in CSF
 Clinically defined as syndrome characterized the onset
of meningeal symptoms over the course of hours to up
to several days .HA is a prominent early symptom
followed by confusion and coma.
 Blurs into chronic meningitis( onset weeks to months)
and encephalitis which is distinguished by decreased
mentation with minimal meningeal signs.

3. Differential Diagnosis of Acute
Meningitis
 Infectious
 Virus-nonpolio enterovirus,arbovirus,herpesvirus, LCM virus,
HIV, adenovirus, influenza
 Richettsia
 Bacteria-H influ, N mening, S pneum, Listeria, E coli, Strep agal,
propionobacteria,staph, enterococcus, Klebs, Salmonella,
Norcardia, Strep pyogenes, MTB,
 Spirochetes
 Protozoa/helminths-
naegleria/angiotrongylus/strongyloides/baylisascaris
 Other infectious syndromes-parameningeal
focus/IE/postinfectious/postvaccination
 Noninfectious-tumors/medications/SLE/seizures/migraine

4. CHANGING EPIDEMIOLOGY
 Since the introduction of H.influenza(1990) and
Streptococcus pneumonia conjugate vaccine
(PCV7)(2000) decreased frequency and peak
incidence has shifted from children<5 to adults
median age 39. Highest case fatality rates among
ages >65
 90% reduction in incidence of invasive H
influenza infection.

5. icaac/idsa 2008 abstact g-761
Impact of PCV7
 CDC study- compared rates of IPD(invasive pneumococcal disease) reported
to 8 US sites participating in Active BacterialCore Surveillance from 1998-
1999 and 2006
 Decreased incidence from 24.4 to 13.5/ 100,000(45%)
 IPD due to vaccine serotypes declined 15.5 to 1.3/100000
 Nonvaccine serotypes increased 6.1to 7.7/100,000.Serotype 19A form .8-2.7
 11-15,000 cases of IPD annually in <5 and 9-18,000fewer annually >5.
 10,000 fewer deaths, .170,000 cases of IPD prevented with vaccine since
introduction
 Increase in antibiotic nonsusceptible strains in 2006
 75% of strains serotype 19A

9. CDC PNEUMOCOCCAL serotype
19 A SURVEILLANCE
 Absolute rate increase in children <5 2006
compared to 2000 -12%
 In adults-over 65-5%

10. ICAAC/IDSA 2008 ABSTRACT G-2075
SEROTYPES CAUSING IPD IN
HIGH HIV PREVALENCE POP
 IPD SURVEILLANCE IN 3 NEWARK HOSPITALS(hiv
PREV 2%)-BLOOD/CSF CULTURES 12/07-4/30/08
 41/48 ANALYZED FOR SEROTYPE
 37 ADULTS(MEDIAN AGE 52)AA76%,HISP24%,HIV32%
 31(94%) NONVACCINE SEROTYPE(NVT)-19A (39%)
 9(22%)PCN RESISTANT-19A 7/9


11. Specific Organisms
 Multicenter study in US in 1995 (after H influ
vaccine) frequency of pathogen varied with age.
Reduction of 55% compared with 1985
 Adults less than 60, S pneu. -60%, N.mening-
20%, H influenza -10%,Listeria-6%, GBS -4%
 Over 60, S pneum-70%, Listeria 20%,
GBS/N.meningitis/H influenz-3-4%

12. Meningitis Mortality by Pathogen

13. Pneumococcal meningitis mortality
by age

15. Mortality and development

17. PATHOGENSIS

22. TREATMENT GUIDELINES

23. NEJM 12/31/01 345:24:1727

25. Head CT prior to LP
 Risk of herniation after LP varies among studies
 Study from 1959-129 patients with increased ICP- 1.2% with
papilledema/12% without herniated after LP
 LP results in small transient decreases in CSF pressure throught subarachnoid
space as a result of removal of fluid and continued leakage.
 Herniation may occur in space occupying inflammatory
lesions(empyema/abscess/toxo),tumor, hemorrage esp rapidly expanding.
Also with meningitis with inc ICP with cerebral edema, thrombosis of sagital
sinus, occlusion of villi. Herniation may also occur without LP
 1995-1999, 301 adults (>16)with clinically suspected meningitis presenting to
Yale ED prospectively evaluated to identify clinical and lab features that
would predict CT abnormalities.
 235(78%) had CT before LP

26. CT before LP
 96/235 had none of these risks
 3/96 had abnormal CT findings but no
herniation.
 4/235 had mass effect and no LP performed
 LP delayed average of two hours in group
undergoing CT
 Even with normal CT, clinical signs suggestive
of high ICP should caution against LP

31. Introduction
 Unfavorable neurological outcomes not
completely the result of inadequate treatment
with antibiotics. CSF cultures are sterile within
24-48 hours after starting antibiotics. In animal
studies, pneumococcal and gram
negative(meningococcus/H flu) induce
meningitis and death. Steroids reduce both csf
inflammation and neurologic sequelae in some
infections.

32. Dexamethsone in adults with
meningitis
 Radomized placebo controlled double blind multicenter study with 301
patients from Netherlands,Austria,Germany,Belgium,Denmark
 Patients> 17 with suspected meningitis randomized to receive dexa 10 mg q 6
x4 days or placebo given 15-20 minutes before antibiotics
 8 weeks after enrollment, percentage of patients with unfavorable
outcome(15%vs 25%)and death(7%and 15%) was significantly lower in the
dexa group.
 Patients with pneumococcal meningitis , more significant benefit with
unfavorable outcome (26%vs52%) and death (14%vs 34%)
 No benefit with other pathogens
 Greatest benefit with moderate to severe GCS score
 All pneumococcal isolates susceptible to Pen

35. IDSA recommendations
 Dexamethasone >15mg/kg q6h fpr 2-4 days with the
first dose 10-20 minutes before or with the first dose of
anibiotics
 Continue if csf gram stain with gram pos diplococci or
cultures positive for pneumococcus
 Do not use in patients who have already received
antibiotics
 Unknown benefit with resistant pneumococcus.
 Dexa decreases vanco penetration

36. Csf diagnostic tests
 Opening pressure->200mm
 Pleocytosis-.1000 ( range <100,>10,000)
 Nuetraphilic predominance(10% lymphocytic)
 Serum glucose/csf glucose <.4
 Elevated protein
 Csf culture positive 70-85% without antibiotics

37. Csf diagnostic tests
Gram Stain
 Gram stain-accurate id of organism-60-90%
 Dependent on concentration of bacteria and
organism-S pneum-90% cases, h.infl-86%, n
mening- 75%,gram neg-50%,listeria-30%
 20% lower with prior antibiotics
 False positive-contaminated with skin fragment

38. Csf diagnostic tests
latex agglutination
 Most useful in patients treated with antibiotics
and whose gram stain and culture are negative
 901 csf bacterial antigen tests performed over
37 months-no modification of therapy in 22/26
positives
 344 csf specimens-10 true pos( pos culture)-3
false neg/2 false pos. no change in management

39. Lab testing to distinguish viral from
bacterial etiology
 PCR more sensitive than viral culture-sens 86-
100%,specificity 92-100%
 CRP- high negative predictive value – normal
without meningitis

40. Treatment

42. Synergy of Vancomycin and
Ceftriaxome in experimental
meningitis

43. Antibiotics and release of LTA and
TA

44. Rifampin and treatment of
pneumococcal meningitis
 AAC 2003-Gerber et al
 Rabbits with pneumococcal experimental
meningitis treated with rifampin followed by
ceftriaxone.
 Significant decrease in LTA and neuronal
apoptosis on autopsy.

45. Duration of treatment