Stiffness, spasticity, or both: a case report of stiff-person syndrome.

Stiffness and spasticity are common neurologic symptoms that affect limb movements. We describe a patient who presented with ill-defined stiffness and an exaggerated startle response, who on serial examinations had variable degrees of stiffness and marked hyperreflexia but with plantar flexor signs. Stiff-person syndrome (SPS) was considered when axial stiffness became evident and was confirmed with highly elevated anti-GAD antibody titers. A favorable response to a short course of intravenous immunoglobulin treatment was sustained for more than 10 months, an unusual feature to the disease. We review the clinical features, pathologic mechanism, and treatment of this disorder.