Autoimmune Encephalitis Misdiagnosis: A Review of Reported Cases

Objective To identify autoimmune encephalitis (AE) mimics and clinical features reported in the literature. Background Recent evidence suggesting that AE is as frequent infectious has increased awareness testing for immune-mediated causes of neurological impairment. Consistent with this theme, several publications have focused on patients whom a diagnosis was initially overlooked. On contrary, remains rare practice, opening up possibility symptoms, signs, test findings associated other etiologies to be misattributed AE. Design/Methods Case reports published PubMed English language before 04/2022 were reviewed. Cases clearly suspected during diagnostic work-up or misdiagnosed included. Results A total forty-five final different from included 40 reports. Median age 52 (range 5-86) years; 30/45 (67%) male. Twenty-eight fulfilled criteria possible (62%), five definite (11%), twelve neither (27%). Features suggestive acute/subacute altered mental status (ranging abnormal behavior coma), (82%); new-onset refractory epilepticus, (7%); CSF pleocytosis (42%) oligoclonal bands (9%), apparent response immunotherapy (38%). In 26 cases, imaging corresponded anatomical classification limbic encephalitis, 15 had one more cortical/subcortical T2-abnormalities, meningeal involvement, brainstem two normal MRI. 12 patients, clinically not relevant neural autoantibodies detected serum and/or CSF, including GAD, Anti-Zic4, CASPR2, VGKC, anti-N-type calcium channel antibody, anti-LGI1, GQ1B. We identified four common mimic categories: neoplasms (15 patients), diseases (9 genetic neurodegenerative (7 patients). Five etiologies. Conclusions Despite well-defined criteria, misdiagnosis encompasses atypical presentation disorders less likely diagnoses.