A case of immunotherapy‐responsive autoimmune hemichorea.

Introduction: Subacute adult‐acquired hemichorea is a striking presentation with a broad differential, including ischemic, metabolic, and inflammatory causes. Case: We encountered a 74‐year‐old woman with rapid onset of hemichorea and associated encephalopathy. Following a thorough workup without identification of clear imaging or laboratory abnormalities, we empirically treated with IVIg. Her hemichorea dramatically improved. Due to relapses of hemichorea, she required repeat immunotherapy with IVIg or high dose steroids followed by maintenance mycophenolate. Discussion: This case of seronegative autoimmune hemichorea highlights the importance of a high index of suspicion for an inflammatory etiology of chorea when other causes are ruled out and performing an immunotherapy trial. [ABSTRACT FROM AUTHOR]