Clinical and imaging characteristics of 16 patients with autoimmune neuronal synaptic encephalitis

Autoimmune neuronal synaptic encephalitis (AIE) encompasses a heterogeneous group of disorders characterized by immune-mediated neuronal cell destruction. In this study, we aim to study the clinical features, imaging profile and treatment outcome of patients with AIE.

This is a chart review of 16 (M: F-3:13) patients with AIE from 2011 to 2015.

Among the patients, 10 had anti-NMDA, 4 had anti-TPO, and 2 had anti-VGKC antibody positivity. Cognitive impairment and seizures were the predominant symptoms present in nearly all patients, followed by psychiatric disturbances (87.5%), mutism (62.5%), movement disorders (62.5%), myoclonic jerks (37.5%) and visual hallucinations (18.75%). Magnetic resonance imaging (MRI) of the brain was available in 15 patients; it was abnormal in 53.3% patients. Abnormalities were seen in all patients with anti-VGKC positivity; and, 60% of patients with anti-NMDA positivity. Imaging was normal in 26.7% of the patients (3: anti-NMDA; and, 1: anti-TPO positivity); and, diffuse cerebral atrophy was noted in rest of the 20% (3: anti-TPO positivity) patients. All patients improved gradually with immunomodulation.

All patients with anti-VGKC, anti-NMDA and anti-TPO antibody positivity presented with a triad of behavioral changes, impaired cognition and seizures. Mutism was a predominant symptom in patients with an anti-NMDA antibody positivity, which may help in the early identification of this disorder. MRI brain showed changes restricted to limbic structures in anti-NMDA and anti-VGKC antibody positivity. An early diagnosis and treatment of autoimmune encephalitis is essential for a better outcome and for prevention of long-term sequel.