Variations of movement disorders in anti-N-methyl-d-aspartate receptor encephalitis: A nationwide study in Taiwan

Anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis is one of the most common autoimmune encephalitis that presents with a wide variety of movement disorders. The purpose of our study is to review the manifestations and duration of movement disorders in different ages with NMDAR encephalitis.A retrospective cohort of 28 patients (20 females and 8 males) with positive cerebrospinal fluid (CSF) anti-NMDAR antibody in a 5-year period from major hospitals in Taiwan was enrolled. They were categorized into 3 age groups: 7 patients were 10 years, 14 patients were 10 to 18 years, and 7 patients were >18 years.Total 28 patients (20 females and 8 males) with age ranging from 8 months to 38 years were enrolled. Nearly all patients (n=27/28, 96%) presented with at least 2 types of disorders, including orofacial-lingual dyskinesia (OFLD; n=20), catatonia (n=19), tremor (n=11), bradykinesia (n=11), dystonia (n=11), choreoathethosis (n=9), and ballism (n=3). Only 1 patient below 10 years presented with isolated periodic choreoathethosis without other movement disorders. OFLD was common in all age groups. Choreoathetosis was most common in patients aged 10 years, while catatonia was most common in patients aged >10 years (P=0.001 and 0.020, respectively). Bradykinesia was also more common in patients aged >10 years (P=0.020). The clinical presentations of movement disorders were not significantly different in the age of 10 to 18 years and those >18 years. Neither patient 10 years old nor male patients had associated tumors. All patients' movement disorders were improved after treatment, while female patients with tumors had worse short-term outcome (P=0.014). Compared with other disorders, choreoathetosis persisted significantly longer in patients 10 years (P=0.038), while OFLD and catatonia last longer in patients >10 years (P=0.047 and 0.002, respectively).Our study shows that hyperkinetic movements such as choreoathetosis are more common and last longer in younger age groups, whereas hypokinetic movements such as catatonia and bradykinesia are more common and last longer in older age groups. Female patients with ovarian tumors had worse short-term outcome.