Red Flags in Suspected AIE
Clinical Red Flags
- Insidious course. (Of note, some types of AIE can present with a chronic course including AIE associated with: Anti-LGI1 Ab, Anti-CASPR2 Ab, Anti-DPPX Ab or Anti-IgLON5 Ab).
- Normal neuropsychological testing results.
- A presentation consistent with a functional neurological disorder.
Reference: Flanagan EP, Geschwind MD, Lopez-Chiriboga AS, et al. Autoimmune Encephalitis Misdiagnosis in Adults. JAMA Neurol. 2023;80(1):30-39. doi:10.1001/jamaneurol.2022.4251
Radiological Red Flags
- Worsening lesions despite immunotherapy.
- Progressive atrophy.
Reference: Flanagan EP, Geschwind MD, Lopez-Chiriboga AS, et al. Autoimmune Encephalitis Misdiagnosis in Adults. JAMA Neurol. 2023;80(1):30-39. doi:10.1001/jamaneurol.2022.4251
Serological Red Flags
- Low Anti-GAD-65 titer (Anti-GAD-65 neurological autoimmunity is typically associated with very high levels of Anti-GAD-65 Ab in serum > 10000 IU/ml by ELISA testing or >20 nmol/L by radioimmunoassay).
- Isolated positive serum Anti-NMDA Ab with negative CSF testing.
- Isolated blot testing positivity (without tissue indirect Immunofluorescence/ Immunohistochemistry confirmation.
Reference: Flanagan EP, Geschwind MD, Lopez-Chiriboga AS, et al. Autoimmune Encephalitis Misdiagnosis in Adults. JAMA Neurol. 2023;80(1):30-39. doi:10.1001/jamaneurol.2022.4251