Internal medicine

Pediatrics

Virus

Disease

Mycoplasma pneumoniae

Streptococcus pneumoniae

Antibiotics

Encephalitis

Biology

Microbiology

Interquartile range

Prospective cohort study

Immunology

Enterovirus

Acute disseminated encephalomyelitis

Pneumonia

Meningitis

Medicine

Clinical Infectious Diseases

Background We aimed to determine the contemporary causes, clinical features, and short-term outcome of encephalitis in Australian children. Methods We prospectively identified children (≤14 years of age) admitted with suspected encephalitis at 5 major pediatric hospitals nationally between May 2013 and December 2016 using the Paediatric Active Enhanced Disease Surveillance (PAEDS) Network. A multidisciplinary expert panel reviewed cases and categorized them using published definitions. Confirmed encephalitis cases were categorized into etiologic subgroups. Results From 526 cases of suspected encephalitis, 287 children met criteria for confirmed encephalitis: 57% (95% confidence interval [CI], 52%–63%) had infectious causes, 10% enterovirus, 10% parechovirus, 8% bacterial meningoencephalitis, 6% influenza, 6% herpes simplex virus (HSV), and 6% Mycoplasma pneumoniae; 25% (95% CI, 20%–30%) had immune-mediated encephalitis, 18% acute disseminated encephalomyelitis, and 6% anti-N-methyl-d-aspartate receptor encephalitis; and 17% (95% CI, 13%–21%) had an unknown cause. Infectious encephalitis occurred in younger children (median age, 1.7 years [interquartile range {IQR}, 0.1–6.9]) compared with immune-mediated encephalitis (median age, 7.6 years [IQR, 4.6–12.4]). Varicella zoster virus encephalitis was infrequent following high vaccination coverage since 2007. Thirteen children (5%) died: 11 with infectious causes (2 influenza; 2 human herpesvirus 6; 2 group B Streptococcus; 2 Streptococcus pneumoniae; 1 HSV; 1 parechovirus; 1 enterovirus) and 2 with no cause identified. Twenty-seven percent (95% CI, 21%–31%) of children showed moderate to severe neurological sequelae at discharge. Conclusions Epidemic viral infections predominated as causes of childhood encephalitis in Australia. The leading causes include vaccine-preventable diseases. There were significant differences in age, clinical features, and outcome among leading causes. Mortality or short-term neurological morbidity occurred in one-third of cases.

Causes and Clinical Features of Childhood Encephalitis: A Multicenter, Prospective Cohort Study