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

IL1, TNF# #

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