Etiology
Streptococcus pneumoniae is the most common cause beyond neonatal period
Group B Strep (Streptococcus agalactiae) is the most common cause in the neonatal period
Listeria monocytogenes is more common in immunocompromised patients, very young and elderly patients
Staphylococcus aureus is more common in those who have had any form of neurosurgery
Cryptococcus is more common in those with HIV positive and CD4 <100
Neisseria is more common in adolescents
Rocky mountain spotted fever (RMSF) - mid-atlantic areas - Carolinas, Kentucky, Tennessee
Lyme disease - Northeast - Massachusetts, Connecticut, New York and New Jersey
Petechial rash --> Neisseria
Rash on the wrists and ankles with centripetal spread toward the body --> RMSF
h/o Erythema chronican migrans + Facial nerve palsy --> Lyme disease
Pulmonary symptoms + abnormal CXR --> TB
Embolization from infective endocarditis typically causes multiple, small parietal lobe abscesses. This "factoid" is worth knowing because some patients with infective endocarditis present with what clinically looks like multiple small "strokes", and their treatable cardiac disease may be completely unsuspected.
Dx
LP is essential (but ensure there is no sign of increased ICP first)
Meningitis with HIGHEST PROTEIN = TB