Table 1. Baseline characteristics and disease management, outcomes, and etiologies for 751 patients with meningitis or encephalitis, Houston, Texas, USA.

Variable	No. (%)
Baseline characteristic
Adult*	567 (75)
Male	357 (48)
White	306 (41)
Concurrent medical condition
Charlson Comorbidity Index score >1	70 (9)
HIV infection	42 (6)
Clinical features
Encephalitis†	237 (32)
Illness onset during West Nile virus season‡	390 (52)
Testing performed
West Nile virus serology	281 (37)
Other arbovirus serology	174 (23)
Magnetic resonance imaging of brain	290 (39)
Management and outcomes
Admission	725 (97)
Received empirical antibiotic treatment	582 (77)
Received empirical antiviral treatment	193 (26)
Adverse outcome§	85 (11)
Etiologies
Unknown	518 (69)
Viral	160 (21)
Enterovirus	63 (8)
Herpes simplex virus	48 (6)
West Nile virus	32 (4)
Other¶	17 (2)
Bacterial#	43 (6)
Fungal**	15 (2)
Mycobacterium tuberculosis	8 (1)
Noninfectious††	7 (1)

*>18 y of age. Median age 31 (range 2 mo–92 y).
†Possible, probable or confirmed diagnosis of encephalitis (13).
‡Jun–Oct.
§Glasgow Outcome Scale score 1-4 (14 ).
¶Varicella zoster virus (n = 7), St. Louis encephalitis virus (n = 3), acute HIV infection (n = 3), cytomegalovirus (n = 2), Epstein-Barr virus (n = 1), influenza virus (n = 1).
#Streptococcus pneumoniae (n = 15), Mycoplasma pneumoniae (n = 5), Staphylococcus aureus (n = 3), Streptococcus agalactiae (n = 3), Haemophilus influenzae n = 3), Escherichia coli (n = 3), Listeria monocytogenes (n = 2), Enterococcus spp. (n = 2), Neisseria meningitides (n = 2), α-hemolytic Streptococcus (n = 1), Streptococcus pyogenes (n = 1), coagulase-negative Staphylococcus (n = 1), Brucella sp. (n = 1), Treponema pallidum (n = 1).
**Cryptococcus neoformans (n = 14), Histoplasma capsulatum (n = 1). 
††Malignancies (n = 3), systemic lupus erythematosus (n = 1), sarcoidosis (n = 1), acute disseminated encephalomyelitis (n = 1), cerebral aneurysm (n = 1).