Autoimmune and limbic encephalitis: case series with some atypical variables in clinical practice

Autoimmune and limbic encephalitides are still rare diseases characterized by rapid diagnostics and treatment development in recent years. The incidence of anti-N-methyl-D- aspartate receptor [NMDAR] encephalitis is about 1.5 per million person per year, and the incidence of paraneoplastic neurological syndromes [PNS] including limbic encephalitis [LE] is about 1.22 per 100 000 person per year (Vogrig et al. J Neurol 267:26-35, 1; Dalmau et al. Ann Neurol 61:25-36, 2). The diagnostic criteria of anti-NMDAR encephalitis are already well established (Zuliani et al. Neurol Sci 40:2017-2030, 10). We provide immunological and clinical characteristics of anti-NMDAR encephalitis case series emphasizing unusual association with colon tumour in one case and complete recovery in two cases. Then we report two cases of onconeural and cell surface antibody negative limbic encephalitis [LE] associated with tumours, seizures, cognitive and behavioural changes resulting in severe cerebellar syndrome and fatal outcome. The clinical characteristics and results of selected paraclinical examinations as electroencephalography [EEG], magnetic resonance imaging [MRI] and cerebrospinal fluid [CSF] analysis are reviewed.