THU289 Hemichorea-Hemiballismus Syndrome Secondary To Steroid Induced Hyperglycemia In A Nondiabetic

Disclosure: E. Krishnaraju: None. K.N. Patolia: None. U.A. Ogar: None. S. Karki: None. A.G. Olafimihan: None. Introduction: Hemichorea-Hemiballismus syndrome (HCHB) associated with nonketotic hyperglycemia is a rare cause of acute to subacute acquired chorea. The syndrome is usually characterized by unilateral choreiform movements, poorly controlled diabetes mellitus, and striatal abnormalities on an MRI of the brain. Clinical Case: This is a case of a 70-year-old man with a history of congestive heart failure, hypertension, remote ischemic stroke, asymptomatic Paget's disease of the bone, chronic kidney disease, and statin-induced necrotizing myositis. Five months before his presentation, the patient was initiated on prednisone for myositis. On presenting to the ED, he had near resolution of his limb weakness from myositis but complained of one month of right-sided continuous involuntary tremors involving the right upper limb, lower limb, and face that resolved during his sleep. There was no family history of neurologic disorders or any history to suggest medication or illicit drug-induced movement disorders. On examination, the patient had normal cognitive functions and vital signs. Neurologic examination was remarkable for quick interspersed moderate amplitude choreiform movements of the right hand, forearm, proximal arm muscles, and right leg. Laboratory results revealed hyperglycemia and a newly elevated Hemoglobin A1c of 8.5, which was normal the year before. Infectious, hematologic, thyroid disease, and Wilson's disease workups were negative. Cerebrospinal fluid (CSF) analysis was remarkable for elevated glucose and identical oligoclonal bands in the serum and CSF, possibly suggestive of a nonspecific chronic systemic inflammatory state. Autoantibodies for paraneoplastic syndromes and autoimmune diseases, including autoimmune encephalitis were negative. There was also no evidence of occult malignancy on CT imaging of the chest, abdomen, and pelvis. MRI/MRA was significant for new small foci of susceptibility artifact in the bilateral basal ganglia, left cerebellar hemisphere, and cerebellar vermis, likely from chronic microvascular changes. The constellation of hemichorea and new onset hyperglycemia in the setting of a largely nondiagnostic workup raises suspicion for HBHC syndrome. Previous studies have found classic T1-weighted MRI hyperintensities in the basal ganglia, but normal imaging does not rule out a diagnosis of diabetic striatopathy. The patient was eventually discharged with mild improvement of his chorea after starting insulin and risperidone. Unfortunately, he was lost to follow-up and unexpectedly died of an unclear cause soon after. Conclusion: Metabolic complications of diabetes can manifest in complex ways. Non-ketotic hyperglycemic HCHB due to diabetic striatopathy is a rarely reported entity that is commonly misdiagnosed. This case is a unique presentation in a non-diabetic patient with steroid-induced hyperglycemia. Presentation: Thursday, June 15, 2023