Table 1.
Etiologies of Cases ≤30 Years of Age Enrolled in the California Encephalitis Project September 2007–February 2011
| Anti-NMDAR (n = 32) | Enterovirus (n = 30) | HSV-1 (n = 7) | VZV (n = 5) | WNV (n = 5) | |
| Demographics | |||||
| Age, median, years | 12.5 (range 2–28) | 8.5 (range 0–22) | 11 (range 1–25) | 11 (range 5–17) | 7 (range 4–20) |
| Gender | |||||
| Female, no. (%) | 24 (75%) | 11 (37%) | 4 (57%) | 3 (60%) | 1 (20%) |
| Ethnicity | |||||
| White, Hispanic, no. (%) | 15 (47%) | 16 (53%) | 1 (14%) | 1 (20%) | 1 (20%) |
| White, non-Hispanic, no. (%) | 2 (6%) | 4 (13%) | 1 (14%) | 2 (40%) | 1 (20%) |
| Black, no. (%) | 4 (13%) | 4 (13%) | 2 (29%) | 0 (0%) | 1 (20%) |
| Asian/Pacific Islander, no. (%) | 10 (31%) | 1 (3%) | 2 (29%) | 0 (0%) | 0 (0%) |
| Other/unknown, no. (%) | 1 (3%) | 5 (17%) | 1 (14%) | 2 (40%) | 2 (40%) |
| Clinical Findings | |||||
| Neurologic Symptoms | |||||
| Movement disorder, no. (%) | 20 (63%) | 2 (7%) | 0 (0%) | 1 (20%) | 0 (0%) |
| Aphasia, no. (%) | 23 (72%) | 3 (10%) | 2 (29%) | 2 (40%) | 1 (20%) |
| Ataxia, no. (%) | 14 (44%) | 6 (20%) | 1 (14%) | 3 (60%) | 2 (40%) |
| Stiff neck, no. (%) | 2 (6%) | 8 (27%) | 2 (29%) | 0 (0%) | 3 (60%) |
| Autonomic instability, no. (%) | 15 (47%) | 0 (0%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Cranial nerve abnormality, no. (%) | 3 (9%) | 2 (7%) | 0 (0%) | 0 (0%) | 2 (40%) |
| Psychiatric Symptoms | |||||
| Hallucinations, no. (%) | 21 (66%) | 3 (10%) | 0 (0%) | 1 (20%) | 0 (0%) |
| Psychosis, no. (%) | 19 (59%) | 1 (3%) | 0 (0%) | 1 (20%) | 0 (0%) |
| Irritability, no. (%) | 24 (75%) | 6 (20%) | 2 (29%) | 2 (40%) | 2 (40%) |
| General Symptoms | |||||
| Fever, no. (%) | 18 (56%) | 18 (60%) | 4 (57%) | 4 (80%) | 5 (100%) |
| GI, no. (%) | 9 (28%) | 11 (37%) | 3 (43%) | 4 (80%) | 0 (0%) |
| URI, no. (%) | 6 (19%) | 8 (27%) | 1 (14%) | 1 (20%) | 0 (0%) |
| Rash, no. (%) | 7 (22%) | 2 (7%) | 1 (14%) | 3 (60%) | 0 (0%) |
| Severe headache, no. (%) | 12 (38%) | 15 (50%) | 2 (29%) | 4 (80%) | 3 (60%) |
| Intubation, no. (%) | 13 (41%) | 7 (23%) | 1 (14%) | 1 (20%) | 2 (40%) |
| ICU admission, no. (%) | 17 (53%) | 13 (43%) | 6 (86%) | 1 (20%) | 3 (60%) |
| Seizures, no. (%) | 22 (69%) | 14 (47%) | 2 (29%) | 1 (20%) | 1 (20%) |
| Coma, no. (%) | 4 (13%) | 3 (10%) | 0 (0%) | 0 (0%) | 1 (20%) |
| Died, no. (%) | 1 (3%) | 2 (7%) | 0 (0%) | 0 (0%) | 0 (0%) |
| Neuroimaging and EEGa | |||||
| MRI | |||||
| Abnormal, no. (%) | 13/28 (46%) | 8/20 (40%) | 6/6 (100%) | 3/3 (100%) | 3/5 (60%) |
| Temporal lobe, no. (%) | 4/28 (14%) | 1/20 (5%) | 6/6 (100%) | 0/3 (0%) | 0/5 (0%) |
| White matter involvement, no. (%) | 3/28 (11%) | 1/20 (5%) | 1/6 (17%) | 0/3 (0%) | 1/5 (20%) |
| EEG | |||||
| Abnormal, no. (%) | 21/24 (88%) | 6/11 (55%) | 3/4 (75%) | 0/0 (0%) | 3/4 (75%) |
| Slowing, no. (%) | 9/24 (38%) | 3/11 (27%) | 2/4 (50%) | 0/0 (0%) | 3/4 (75%) |
| Epileptiform activity, no. (%) | 6/24 (25%) | 1/11 (9%) | 1/4 (25%) | 0/0 (0%) | 0/4 (0%) |
| Laboratory | |||||
| CSF median values (range) | |||||
| WBC count, cells/mm3 | 23 (0–252) | 70 (1–2655) | 78 (3–540) | 167 (43–705) | 189 (17–645) |
| Protein level, mg/dL | 24 (10–67) | 34 (10–131) | 52 (6–126) | 70 (30–119) | 65 (48–179) |
| Glucose level, mg/dL | 64 (35–92) | 64 (42–122) | 55 (34–79) | 56 (40–58) | 59 (39–63) |
Abbreviations: CSF, cerebrospinal fluid; EEG, electroencephalogram; GI, gastrointestinal; HSV-1, herpes simplex virus type 1; ICU, intensive care unite; MRI, magnetic resonance imaging; NMDAR, N-methyl-D-aspartate receptor; URI, upper respiratory infection; VZV, varicella-zoster virus; WBC, white blood cell; WNV, West Nile virus.
aNeuroimaging data was not provided for some patients in the study. Notably, no EEG reports were provided for patients with VZV illness.