Acute disseminated encephalomyelitis in children - clinical and MRI decision making in the emergency department.

Background: Acute disseminated encephalomyelitis (ADEM) is an uncommon, treatable, primarily pediatric, immune-mediated disease. Diagnosis of ADEM requires two essential elements: typical clinical presentation and magnetic resonance imaging (MRI) findings. The aim of this study was to evaluate how clinical findings in the initial emergency department (ED) presentation influenced the timing of MRI.

Methods: A retrospective chart review was conducted of children diagnosed with ADEM, over a 12-year period, in a tertiary care pediatric center. Clinical presentation at ED admission was recorded and patients who underwent an MRI as part of their ED evaluation (early MRI) with those who had MRI performed during ward hospitalization (late MRI) were compared.

Results: 30 patients were diagnosed with ADEM during the study period. Encephalopathy and polyfocal neurological signs were described in 80% and 50% of patients ED charts, respectively. Seven patients underwent early MRI and polyfocal neurological signs were more common in this group (p = 0.006). Fever was more common in the late MRI group (p = 0.02). Following diagnosis, all patients were treated with immune-modulation therapy, improved clinically, and were discharged.

Conclusion: 20% of ADEM patients were not encephalopathic at ED presentation. Polyfocal neurological signs and absence of fever at ED presentation were related to earlier MRI utilization and thus earlier diagnosis and treatment. Familiarity with the ADEM constellation of signs, and a high index of suspicion, may help the ED clinician in early diagnosis and treatment of this rare disease.