Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis: A series of ten cases from a university hospital in Malaysia

ABSTRACT

Objective: To report on the incidence, and the clinical and laboratory features of patients seen at the University of Malaya Medical Centre with anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis. Methods: The charts of all patients admitted to the adult neurology ward with encephalitis over an 18- month period from January 2010 to June 2011 were reviewed. Diagnosis of anti-NMDAR encephalitis was based on the presence of encephalitis plus antibody against the NMDAR. Two other paediatric patients with anti-NMDAR encephalitis seen over the same period were also included in this report. Results: There was a total of 10 patients with anti-NMDAR encephalitis seen over the study period. The mean age was 18.1 years (range 9-29 years). Eight patients were female, two male. Five were Malay and fi ve were Chinese. All patients had prominent psychiatric symptoms, followed by epileptic seizures. Nine patients had a movement disorder, orofacial dyskinesia being the commonest, and all had autonomic involvement. None had an underlying tumour. Treatments consisted of corticosteroid, plasma exchange and intravenous immunoglobulin (IVIG). The clinical outcome was variable, with full recovery (2), substantial recovery (3), partial recovery (4), and mortality (1) seen. Remarkably, the eight adult cases of anti-NMDAR encephalitis accounted for 50% of the 16 cases of encephalitis seen during the study period. Conclusion: Anti-NMDAR encephalitis may be a relatively common cause of adult encephalitis among certain Asian groups. None of our cases was paraneoplastic in origin.