Aggravation of stiff-person syndrome with ophthalmoplegia after tandospirone initiation: a case report.

Background: Stiff-person syndrome (SPS) is a rare neuroimmune disorder that is associated with a variety of symptoms and varying degrees of disability. SPS has multiple phenotypes and different immunological bases, and the lack of clinical awareness of these various clinical phenotypes often leads to misdiagnosis and inappropriate treatment of SPS patients in the early stage of the disease course. Case description: We report a distinctive case of SPS with a 4-year follow-up. The patient was a 56-year-old middle-aged woman who initially presented with diplopia and atypical muscle tension. Treatment with baclofen and lorazepam showed poor efficacy, and she was once misdiagnosed with anxiety and depression as well as oculomotor nerve palsy. During the 4-year follow-up period, the patient gradually developed typical clinical manifestations and signs of SPS and was diagnosed with positive GAD antibodies. In the later stage, the patient's symptoms were exacerbated by the serotonin receptor partial agonist tandospirone; further testing revealed a significant increase in GAD antibody titer. Results: As the patient could not tolerate hormone pulse therapy, she was administered rituximab and two sessions of intravenous immunoglobulin (IVIG). After adjustment of the relevant treatment regimen, the patient's symptoms were significantly alleviated. Conclusion: SPS is relatively uncommon and prone to misdiagnosis. Therefore, we need to understand the various clinical manifestations of SPS, achieve early intervention, and thereby improve the prognosis and quality of life of patients.