Unanticipated improvement of stiff person syndrome aftersevere COVID-19

Objective: We describe a patient with stiff-person syndrome (SPS), who had only minimal improvement on weekly intravenous immunoglobulin (IVIG) for 3 years, but improved significantly after treatment with tocilizumab for Coronavirus Disease (COVID-19). Background: NA Design/Methods: 51-year-old woman with history of Diabetes mellites and temporal lobe seizures, presented initially in 2014 with episodes of right leg stiffness, painful tonic spasms and falls. She was diagnosed with SPS in 2017. Her cerebrospinal fluid analysis was positive for antiGlutamic acid decarboxylase (GAD) antibodies. She was started on IVIG and botulinum toxin injections. There was only minimal improvement as she continued to have multiple episodes of tonic spasms daily and needed one-person support with a walker to ambulate. In April 2020, she was admitted for COVID-19 infection complicated by acute respiratory distress syndrome (ARDS), which necessitated intubation, sedation and mechanical ventilation. During her hospitalization she received hydroxychloroquine, azithromycin, convalescent plasma and tocilizumab (400mg/2 doses at an interval of 2 weeks). After being weaned off sedation, she observed that stiffness of right lower extremity had significantly improved, and she no longer had any tonic spasms. She was able to walk without support and continued to do so at 3-month follow up. Her glucose control has also improved significantly requiring less insulin. Results: NA Conclusions: We hypothesize that tocilizumab is the likely cause of significant improvement in our patient's condition. Anti-GAD antibodies are known to elicit T-Helper 2 response, which increases production of cytokines such as Interleukin (IL-4) and IL-6. Tocilizumab, an IL-6 inhibitor, has shown significant clinical improvement in patients with other autoimmune encephalitis who were refractory to rituximab in case-control studies. This has never been studied in SPS. We suggest that it may be a feasible option to consider for patients with SPS, who are refractory to traditional treatments including weekly IVIG.