ID 17: Meningitis
Pathogenesis
Presentation
Management
Intro
Bacterial Meningitis Bugs
Diagnosis
Symptoms
Inflammation of meningies. Can be infectious or not
Epi
Bacterial
1.4 cases per 100k
Incidence higher in developing world (30x)
Viral
10.9 cases per 100k
More common in children
Mucosal Colonization
Bacteremia
Meningial invasion (cross BBB/B-CSF-B)
Release of bacterial component (e.g. LPS)
Macro + Neutrophil
Sub-Arachnoid Inflammation
Inc BBB permeability
Cerebral vasculitis
Vasogenic edema
Inc resistance to CSF outflow
Interstitial edema
Inc Intra-Cranial Pressure
Cytotoxic Edema
Cerebral Infarct
Events
Intravascular Survival
Meningeal Invasion
Mucosal Colonization
Virulence
Host
Fimbriae, capsule, IgA protease, bacteriocins
Epithelia, sIgA, Capsule Ab, Pili phosphotransferase
Virulence
Host
Capsule
Complement, Ab, Migration inhibitory factor
Virulence
Host
Fimbriae, monocyte invasion
BBB, B-CSF-B
Survive Subarachnoid
Virulence
Capsule
Host
CSF is poor opsonin
Head trauma/surgery
Basilar skull fracture, CSF leak
By Age
1-23 mo.
1 yr to 18 yr
<1 mo
50 yo
E. coli
Listeria
S. agalactiae (early = <7days)
E. coli
H. flu
Strep agalactiae, pneumo
N. meningitidis
N. meningitidis
H. flu
S. pneumo
N. meningitidis
Listeria
S. pneumo
G- aerobic bacilli
Staph epidermidis
G- aerobic bacilli
Staph aureus
H. flu
Group A beta-hemolytic strep
S. pneumo
Early vs. Late
Adults
Children
General
Risk Factors
Headache, stiff neck
Photo/Phono phobia
Fever
Nausea, vomitting
Change in mental status
Mental status change (69%)
Neurological focal (33%)
Rash (26%)
Fever (77%)
Stiff Neck (83%)
Neonates
Older children
Irritability
Poor feeding
Fever
Bulging fontanel
Like adults
Head trauma (CSF leak)
Imm-suppression (e.g. N. meningitidis)
Pneumoina, sinusitis
Alcoholism
Otitis media, mastoiditis
Prognosis
CT scan
Lumbar puncture STAT
Bacterial Ag
Altered mental status
Imm-compromised
Focal neuro lesion/seizure
Age >60
Papilledema
Gram stain + Culture
Protein, glu, cells
PCR for viral
17 yr to 50 yr
N. meningitidis
S. agalactiae
S. pneumo
Not very sensitive for G- (Listeria)
Early
Late
Coagulaopathy (DIC)
Resp. failure (resp distress syndrome)
Early
Cerebral edema
Hearing loss
Seizure
Behavior, learning disability
Hydrocephalus
Corticosteroids
Supportive for the complications
Antibiotics
Based on bug
Mortality
S. agalactiae 27%
N. meningitis 13%
S. pneumo 26%
H. flu 6%
L. monocytogenes 29%
Risk Factors
Obtund mental status
Seizure within 24 hours admission
Age >60
Low WBC, thrombocytopenia
Bactermia, no rash
Aseptic Meningitis
Caused by enterovirus
Bacterial vs. Aseptic CSF Meningitis
Culture negative meningitis
In adults with less severe symptoms
Community epidemic ; late summer/fall
More common in infant/children
Bacterial
Aseptic
Inc protein, WBC. Dec glucose
Inc WBC. Normal protein, glucose. Dec PMN