Up to age 60:

S. pneumoniae 60%

N. meningitidis 20%

H. influenzae 10%

L. monocytogenes 6%

group B streptococcus 4%

Age 60 and above

S. pneumoniae 70%

L. monocytogenes 20%

group B streptococcus 4%

N. meningitidis 3%

Up to age 60: GNB 33%

Streptococci 9%

Staphylococcus aureus 9%

Coagulase-negative staph 9%

S. pneumoniae, N. meningitidis, and L. monocytogenes 8%

Risk Factors: neurosurgery

head trauma

neurosurgical device

CSF leak

Organism Site of entry Age rangePredisposing

conditions

Neisseria

meningitidisNasopharynx Childhood-mid 20's

Usually none, rarely

complement deficiency

Streptococcus

pneumoniae

Nasopharynx or direct

extension across skull

fracture

All ages

All conditions that

predispose to

pneumococcal

bacteremia

Listeria

monocytogenesGI tract, placenta All ages

Defects in cell mediated

immunity

Coagulase-negative

staphylococcusDermal or foreign body All ages

Surgery and foreign

body, especially

ventricular shunt

Staphylococcus

aureusBacteremia, dermal, or

foreign bodyAll ages

Endocarditis, surgery

and foreign body,

especially ventricular

shunt

Gram negative rods VariousAll ages, especially the

elderly

Advanced medical

illness, neurosurgery

Haemophilus

influenzae Nasopharynx

Adults now, but infants

and children if not

vaccinated

Diminished humoral

immunity

predisposing factors Recent exposure to someone with meningitis

A recent infection (especially respiratory or otic infection)

Recent travel, particularly to endemic meningococcal areas

Injection drug use

Recent head trauma

Otorrhea or rhinorrhea

A progressive petechial or ecchymotic rash

Host problem Organism favored

Frequency of defect

actually leading to

infection

Absence of opsonizing

antibody

S. pneumoniae Common in all age groups

H. influenzaeCommon in very young

children

Asplenia

surgical / functional

S. pneumonia Rare

N. meningitidis Very rare

Complement deficiency N. meningitidis Very rare

Corticosteroid L. monocytogenes Rare

C. neoformans Rare

HIV infection

C. neoformansAbout five percent eventually

get cryptococcal meningitis

S. pneumoniae Common presenting illness

L. monocytogenes Rare

Bacteremia/EndocarditisS. aureus various gram-negative

rodsRare

Basilar skull fractureS. pneumoniae or other oral

floraVery rare

Presenting manifestations

Fever was present in 95%

Neck stiffness was present in 88%

Mental status was altered in 78%

Headache 79%

Neurologic complications:

neurologic deficits 20%

Seizures 15%

Photophobia

Jolt accentuation of headache •sensitivity of 97 %

•specificity of 60 % for the diagnosis of CSF

pleocytosis

•Untreated or delayed treatment “FATAL”

•Markers for bad prognosis:

•Hypotension

•altered mental status

•seizures

• In-hospital mortality 27%

•Neurologic deficit on discharge 9%

CBC-D / BMP

Blood cultures positive in 50 to 75%

•Immunocompromised state.

•History of CNS disease.

•New onset seizure (within one week)

•Papilledema

•Abnormal level of consciousness

•Focal neurologic deficit

•Prior administration of antimicrobials tends to have

minimal effects on the chemistry and cytology

findings

• can reduce the yield of Gram's stain and culture

Opening Pressure

•cell count and differential

•glucose

•protein concentration

• Gram's stain

•Culture & sensitivity

Normal values for CSF analysis

• protein < 50 mg/dL of

•CSF/serum glucose ratio >50%

•WBC < 5 white cells /microL

Glucose (mg/dL) Protein (mg/dL)Total white blood cell count

(cells/µL)

<10* 10-45 >250 50-250 >1000100-

10005-100

More

common

Bacterial

meningitis

Bacterial

meningitis

Bacterial

meningitis

Viral

meningitis

Lyme

diseaseNeurosyphilis

Bacterial

meningitis

Bacterial or

viral

meningitis

Early

bacterial

meningitis

Viral

meningitis

Neurosyphilis

TB meningitis

Less

commonTB meningitis

Fungal

meningitis

Neurosyphilis

Some viral

infections

(such as

mumps)

TB meningitisSome cases

of mumps Encephalitis Encephalitis

•Antibiotic therapy should be initiated

immediately after (LP)

•“if CT scan indicated before LP”, ABx therapy

should be initiated immediately

are obtained

•Antibiotic therapy• Bactericidal

• BBB penetration

•All Abx should be given I.V.

•Empiric drug regimen

•3rd generation cephalosporin:•Ceftriaxone

•Ceftazidime

•Vancomycin

•Ampicillin

•Dexamethasone (0.15 mg/kg every six hours) be given

•Glasgow coma score of 8 to 11

•Therapy for 4 days in pneumococcal meningitis

•I.V.F

Pathogen Antibiotics

S. pneumoniae

•Vancomycin (500 mg Q6h) PLUS

•Ceftriaxone (2 g Q12h) or,

•Cefotaxime (2 g Q4-6h or Q6-8h)

•14 days

N. meningitidis•Penicillin G (4 million units Q4h) for

seven days

H. influenzae•Ceftriaxone (2 g Q12h) or

•Cefotaxime (2 g Q6h)

•7 days

L. monocytogenes•Ampicillin (2 g Q4h)

•Penicillin G (3-4 million U Q4h)

• +Gentamicin (1-2 mg/kg Q8h).

Group B streptococci•Penicillin G (4 million U Q4h)

•2-4 weeks

Enterobacteriaceae

•Ceftriaxone (2 g Q12h) or

•Cefotaxime (2 g Q6-8h) PLUS

•Gentamicin (1-2 mg/kg Q8h)

•3 weeks

Pseudomonas or Acinetobacter•Ceftazidime (2 g Q8h)

•21 days

•4% percent of invasive GBS infections involve (CNS)

•1% of all cases of meningitis.

•GBS meningitis has been described

•following elective abortion

•adult GBS meningitis has been noted recently in Southeast

Asia.

•equally among immunocompromised and immunocompetent

hosts.

•mortality rate of 27%.

•>(65 years) Mortality rate 56%.

•The incidence of infection has a bimodal distribution, with

peaks mid-20s &mid-60s.

•patients present with

•Fever.

•Meningismus.

•neurologic deficits.

•spinal fluid glucose, protein, and cell counts suggestive of

bacterial meningitis

•mortality rates of 15 to 38%