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TABLE 94.9
CAUSES OF ASEPTIC MENINGITIS
Viral

Enteroviral
Herpes simplex virus
Arboviral
Lymphocytic choriomeningitis virus
Mumps
Other viral infections

Bacterial

Early or partially treated bacterial meningitis
Parameningeal infection
Mycobacterium tuberculosis
Borrelia burgdorferi (Lyme disease)
Rickettsial diseases
Bartonella henselae (cat scratch)
Leptospirosis
Treponema pallidum (syphilis)
Mycoplasma

Fungal

Cryptococcus
Histoplasmosis

Parasitic

Candida

Naegleria
Toxoplasmosis
Taenia solium (neurocysticercosis)
Malaria
Trichinosis

Noninfectious

Neoplasia
Kawasaki disease
Hemorrhage
Collage vascular diseases
Hypersensitivity reactions
Heavy metal poisoning
Sarcoidosis

Because the CSF findings in aseptic meningitis overlap those in bacterial infections, hospital admission is
usually warranted until the CSF culture results are available. However, the experienced clinician may choose to
follow the older child as an outpatient if the family is reliable and nonviral causes (e.g., Lyme disease,
tuberculosis, cryptococcosis) are clinically unlikely. To guide clinicians, the Bacterial Meningitis Score has been
derived and validated to identify children at very low risk (negative predictive value 99.7%) for bacterial
meningitis. Low-risk features are negative CSF Gram stain; CSF absolute neutrophil count (ANC) <1,000 cells/
μL, CSF protein <80 mg/dL, peripheral ANC <10,000 cells/mm3, and no seizures at or prior to presentation.
Additionally, a positive rapid enteroviral PCR may support outpatient management if available and the patient is
clinically well.

Encephalitis and Meningoencephalitis