Acute Disseminated Encephalomyelitis: Psychiatric Presentation of a Rare Diagnosis.

Acute disseminated encephalomyelitis (ADEM) is an autoimmune inflammatory disease of the central nervous system that is characterized by widespread demyelination, predominantly involving the white matter of the brain and spinal cord. Often caused by a viral infection or vaccination, its clinical features include an acute encephalopathy with multifocal neurologic signs and deficits in children. It can present with psychosis, depression, or abnormal behavior, and it might mimic a dissociative disorder. This report involves a similar rare case of a 14-year-old female patient who presented with fluctuating weakness of body, slurring of speech, tremor, loss of responsiveness, and abnormal behavior after her fever waned. Diagnosis of dissociative disorder was considered in the absence of neurological findings and ongoing significant stressor. Eventually, it turned out to be ADEM, which was confirmed by late neurological manifestations and radiological evaluation. Neuroimaging also revealed its differences from multiple sclerosis.