2021 Volume 64 Issue 2 Pages 122-127
A 54-year-old woman with rheumatoid arthritis and Hashimoto thyroiditis presented with type 1 diabetes in 2015 due to low serum C-peptide level; therefore, she was diagnosed with autoimmune polyglandular syndrome type 3 (APS3). After a seizure in 2017, she had difficulty walking and decreased memory capacity. A cerebrospinal fluid test revealed an increased number of cells. Brain magnetic resonance imaging also indicated a high fluid-attenuated inversion recovery signal in the left valve lid. She was diagnosed with autoimmune encephalitis. Steroid pulse therapy improved the symptoms of the autoimmune encephalitis. Interestingly, HLA Class II genotyping revealed a common protective HLA allele for Japanese type 1 diabetes. Furthermore, she had a specific antibody for autoimmune encephalitis. By referencing previous reports about clinical characteristics of APS in Japan, we discuss the mechanism of APS3. The combination of APS3 and autoimmune encephalitis is extremely rare, and to our knowledge, this is the first known case among Japanese patients.
