We intended to describe clinical and MRI features of acute brain stem encephalitis in children with attempt on early differentiation between infectious and autoimmune etiologies.

Method: Retrospective chart review of children with acute brainstem syndrome at Children’s hospital of Pittsburgh between January 2006 and February 2017.

Results: 31 children were identified (11 Males, mean age at diagnosis 11.14 years). The etiologies were Multiple sclerosis (7), Clinically isolated syndrome (8), ADEM (4), infectious encephalitis (8), and Rheumatological disorder (2). Two patients were undiagnosed. Clinical presentations included ataxia (58%) cranial nerve palsy (70%) and motor-sensory deficits (68%). Diffusion imaging was positive in five patients (16%) and contrast enhancement of brain stem lesions was noted in 15 patients (48%). CSF studies were available in 27 patients.  18/27 (67%) had pleocytosis (>5WBC/cumm); 7/18 patients also had elevated protein (>45mg/dl).  At least one follow up visit was available in 27 patients. Mean follow up was 10 months. 24 patients had more than 3 months follow up. 21/27 (73%) patients demonstrated improvement by 3 months. There was no statistically significant difference in analysis of various nominal variables (age, sex, CSF WBC, CSF protein, diffusion on MRI and presence of contrast enhancement on imaging between first episode of demyelinating diseases (CIS, ADEM) and probable/definite infectious encephalitis (p value >0.05)

Conclusions: Acute brainstem encephalitis in children is most frequently autoimmune in nature. Initial demographic and imaging features do not help differentiate between infectious or autoimmune etiologies.