Acute motor deficits in a young patient: Looking out for stroke mimics: A case report

This case is unique in emphasising the importance of recognising anti-NMDAR encephalitis as a stroke mimic in paediatric patients, with early diagnosis and appropriate treatment resulting in full recovery. It contributes to the scientific literature by highlighting the critical role of timely diagnosis in distinguishing autoimmune encephalitis from stroke and improving patient outcomes. We present a challenging case of a 13-year-old male who developed sudden left-sided hemiparesis and dysarthria, initially suggestive of acute ischemic stroke. Despite prompt thrombolysis, further investigations, including magnetic resonance imaging (MRI) and lumbar puncture, revealed inflammation, and elevated anti-N-Methyl-D-Aspartate receptor (NMDAR) antibodies confirmed the diagnosis of autoimmune encephalitis. The patient subsequently experienced focal motor seizures, necessitating an escalation in antiepileptic therapy and intravenous immunoglobulin (IVIG) treatment. Electroencephalography (EEG) demonstrated right hemispheric dysfunction, supporting the diagnosis. After two weeks of hospitalization, the patient showed gradual improvement, although mild neurological deficits persisted, prompting treatment with rituximab. Upon discharge, he was seizure-free, and at one-month follow-up, motor deficits had fully resolved, with normal MRI findings and no cognitive impairment. A high index of suspicion for autoimmune encephalitis, particularly anti-NMDAR encephalitis, is essential when standard stroke treatments fail to improve symptoms.