Non-ketotic Hyperglycemia-induced Hemiballism-Hemichorea

Imaging Findings Head computed tomography (CT) demonstrated asymmetric hyperdensity in the right basal ganglia involving the caudate and lentiform nuclei (putamen and globus pallidus), (Figure 1). Traditional research on the pathophysiology of hemiballism-hemichorea points to the role of lesions in the subthalamic nucleus, while more recent research focuses on lesions in the basal ganglia structures or abnormal neuronal firing patterns in these structures.2,3 Hemiballism-hemichorea affects female patients more frequently than male, and is usually late onset.4 Radiologic exams in these cases typically reveal abnormalities in the basal ganglia, especially the putamen, contralateral to the side experiencing involuntary movement.1 CT demonstrates high-attenuation changes, T1 MRI shows hyperintensity, and T2 MRI shows hypointensity or isointensity.1 The intrinsic T1 shortening/hyperintensity may be related to the presence of gemistocytes in the lesion that may be causing a shorter T1 relaxation time.5 Awareness of this unique set of radiologic findings is important to ensure the correct diagnosis. The primary treatment for this disorder is clinically correcting and controlling serum glucose levels in the short-term and long-term.1 Symptoms usually subside after normal metabolism is restored (correction of hyperglycemia).6 The disorder has a favorable prognosis, although 20% of patients may continue to experience hemiballism-hemichorea following clinical treatment.1 Pharmacologic treatment in these cases helps mitigate symptoms.