Autoimmune encephalitis in Hong Kong Chinese patients: experience of a regional hospital

Abstract

INTRODUCTION: Autoimmune encephalitis includes a heterogeneous group of non-infectious neuroinflammation of the brain characterised by detection of autoantibodies targeting a wide variety of neuronal and synaptic antigens in serum and/or cerebrospinal fluid (CSF) of patients. METHODS: Records of patients with a diagnostic code of autoimmune encephalitis confirmed with detection of specific neuronal, glial, or synaptic autoantibodies cared in Queen Mary Hospital from January 2001 to October 2015 were studied retrospectively. RESULTS: A total of 11 patients had symptomatic autoimmune encephalitis confirmed with detection of specific autoantibodies. Eight (72.7%) had neuromyelitis optica spectrum disorders seropositive for aquaporin-4 autoantibodies and had encephalitis involving various brain regions: hypothalamus (2), periaqueductal grey matter (3), periventricular region around fourth ventricle (3), ventral midbrain (3), dorsal pons and cerebellar peduncles (4), medulla commonly in continuity with high cervical myelitis (6) and periventricular white matter in cerebral hemispheres (2) and corpus callosum (1). Two patients had voltage-gated potassium channel complex antibodies detected in sera—one presented with confusion, memory loss, and disorientation with typical magnetic resonance imaging (MRI) brain findings of limbic encephalitis; the other presented with marked weight loss, insomnia, haemodynamic instability, limb weakness, and fasciculation suggestive of central, autonomic, and peripheral hyperexcitability. A single young woman presented with confusion, disorientation, followed by status epilepticus and involuntary facial dyskinesia with normal MRI brain. She had anti-NMDAR antibodies detected in her CSF but not serum, confirming the diagnosis of anti-NMDAR encephalitis. She had no ovarian teratoma or other tumour found. She responded well to pulse steroid and intravenous immunoglobulin during acute phase, and had no relapse for a year while on mycophenolate mofetil. CONCLUSION: Autoimmune encephalitis is a potentially severe but treatable neurological disorder. Detection of specific neuronal, glial, or synaptic autoantibodies greatly facilitates early diagnosis and prompt treatments.