Stiff-Person Syndrome Associated with Anti-Glutamic Acid Decarboxylase Autoimmune Encephalitis in a Young Woman: A Case Report

A 34-year-old female with stiff-person syndrome (SPS) is reported in this paper. She experienced short-term memory impairment and was diagnosed with anti-glutamic acid decarboxylase (GAD) autoimmune encephalitis (AE) at the local hospital. However, after the treatment with intravenous immunoglobulin and high-dose glucocorticoids, her symptoms unchanged. Two months later, she was admitted to our hospital due to an unstable gait and persistent leg stiffness, at which point she was diagnosed as anti-GAD AE concomitant with SPS. Her clinical symptoms improved with an increased dose of γ-aminobutyric acid (GABA)-enhancing drug and plasma exchange. Anti-GAD antibody-associated AE combined with SPS is extremely rare. Treatment with GABA-enhancing drugs and appropriate immunotherapy can improve the neurological function of patients suffering from the combination of SPS and limbic encephalitis.