Stiff Person Syndrome With Positive Anti-glutamic Acid Decarboxylase (GAD) Autoantibodies

Stiff person syndrome (SPS) is a progressive autoimmune disorder characterized by muscle rigidity, frequent falls, and spasms, affecting primarily women. Recent advances have linked SPS to specific antibodies, such as anti-glutamic acid decarboxylase (GAD)-65, but effective treatments remain elusive. We report the case of a 53-year-old female who developed chronic lower back pain, tingling paresthesias, and progressive rigidity in the lower limbs. Electromyographic examination revealed muscle spasms and co-contractions, along with severe rigidity and reactive spasms upon touch. Imaging studies showed a polymyomatous uterus and no hypermetabolic lesions. She was diagnosed with stiff person syndrome with positive anti-GAD65 autoantibodies. Patient was treated with methylprednisolone, oral corticosteroids, gabapentin, baclofen, alprazolam, immunoglobulins, and rituximab, leading to moderate improvement in her condition. This case report aims to highlight the association between SPS and anti-GAD65 autoantibodies, emphasizing the importance of early diagnosis and comprehensive management.