Med in Small Doses - Bacterial Meningitis

This is part of the Med in Small Doses series, which aims to give you a snapshot of a disease or disorder. For information about the series, or common abbreviations click here.

Acute purulent infection of SAS - ↑ ICP, Stroke. Fatal: 5-40%, permanent neuro injury ~10%

PATHO: Invasion of SAS → Inflammatory Cytokines → vasogenic & cytogenic odema, cell death & injury → ICP → Coma → Death

Common Bugs: Explaining Hot Neck Stiffness (young to old)

E.coli [Infants]

H.influenzae [Kids]

N.meningiditis [Adults] – in ~25% of cases

S.pneumonaie [Old] – in ~50% of cases

Also consider Group B Strep and S.aureus (rare, but neurosurgical). NHS is another way of remembering the common pathogens for our UK friends.

CFs: Triad (Fever, Headache, nuchal rigidity). N&V, photophobia, rash, ↑ ICP, seizures (40%) 

RFs: Hx of respiratory illness in the past 2 weeks in 50% of patients.

Ix: Blood Cultures, CT/MRI, LP (↓glu, ↑protein, ↑WBC)

Tx: Begin Abs within 60mins of patients arrival.

Empirical: Dexamethoasone + Ceftriaxone + Vancomycin + Acyclovir (incase of possible viral meningitis) Adjunctive: Dexa (20min before Abs), Mannitol (↓ICP)

Px: Vaccination, Rifampicin (meningococcal), Cephalosporins

The rationale behind prevention, is more to eradicate the reservoir of the pathogen, rather than primary prevention of bacterial meningitis.