Adult Onset Acute Disseminated Encephalomyelitis: A Case Report.

Acute disseminated encephalomyelitis (ADEM) is a rare autoimmune demyelinating disorder of the central nervous system that can mimic other neurological diseases, such as multiple sclerosis. ADEM is thought to manifest in the presence of environmental triggers, namely viral or bacterial infections, with multiple simultaneous neurological deficits, frequently accompanied by encephalopathy. Here, we report the case of a 49-year-old female patient who presented in the emergency department with encephalopathy, right-side muscle weakness, dizziness, vertigo, ataxia, and postural imbalance, preceded by symptoms suggesting recent pharyngitis/sialadenitis three weeks prior. Cerebrospinal fluid analysis revealed lymphocytic pleocytosis, elevated protein levels, normal glucose levels, no oligoclonal bands, and culture and viral studies were negative. After a normal cerebral computed tomography, brain and cervical spine magnetic resonance imaging (MRI) revealed multiple, T2-weighted hyperintense supratentorial and infratentorial white matter lesions, including the right cerebellar peduncle and posterior limb of the left internal capsule. The diagnosis of ADEM was made, and the patient was treated with high-dose intravenous glucocorticoids followed by oral tapering with clinical improvement. During follow-up, the control MRI was compatible with the diagnosis. This case illustrates the diagnostic approach of a patient presenting with subacute neurological deficits and the importance of contemplating possible differential diagnoses and swiftly initiating treatment.