SUMMARY:Hemiballism with corresponding striatal T1 hyperintensity on MR imaging has occasionally been reported in patients with nonketotic hyperglycemia. However, the subthalamic nucleus lesion, which is believed to be pathogenetically related to hemiballism, is rarely documented in a living patient with nonketotic hyperglycemia. We describe a patient with nonketotic hyperglycemia-induced hemiballism, whose responsible lesion (ie, the subthalamus) was demonstrated by MR imaging.
Hemiballism-hemichorea (HB-HC) is an involuntary, irregular, wide-amplitude, and poorly patterned movement disorder. HB-HC can mostly result from a focal vascular lesion in the contralateral basal ganglia.1 In the absence of an identifiable focal vascular lesion, metabolic derangements (eg, nonketotic hyperglycemia or hyperthyroidism), brain neoplasm, and infectious diseases of the central nervous system (eg, human immunodeficiency virus infection) are considered to be the more common causes.1 Recent studies have shown that striatal hyperintensity, seen on the T1-weighted MR imaging of the brain, can occur in the acute stage of HB-HC, caused by nonketotic hyperglycemia.2 These radiologic images provided the clue for the early diagnosis of this dyskinesia. Animal studies and subsequent human studies supported the finding that the subthalamus is strongly related to hemiballism.3 There are only scanty reports documenting the subthalamic involvement of nonketotic hyperglycemia in a living patient, which prompted us to report a case of nonketotic hyperglycemia-induced hemiballism, with the responsible subthalamic lesion confirmed by MR imaging.
Case ReportA 53-year-old woman was admitted for sudden onset of abnormal movement on the left side. This jerky irregular involuntary movement was first noted on the left leg 3 days before admission. Her symptoms worsened during the last 3 days. She had no history of hypertension, diabetes, headache, parkinsonism, or other neurologic diseases. At admission, her initial blood glucose level was 242 mg/dL and her hemoglobin A 1c concentration was 11.7% (normal values are 70 -110 mg/dL and 4.7-6.4%, respectively). The urine specimen was negative for ketones, indicating nonketotic hyperglycemia. A neurologic examination showed her sensorium to be normal. Deep tendon reflexes were symmetrically hypoactive. The remaining results of the examinations were unremarkable, except for left hemiballism. Brain CT, performed on the first hospital day, revealed no abnormalities. The MR image, obtained 4 days after her initial presentation, showed high signal intensities in the right subthalamic nucleus (STN) on T1-weighted and T2-weighted images (Fig 1) and subtle high signal intensities on diffusion-weighted images (DWIs, not shown). Gradientecho images and B 0 images of DWI showed no susceptibility artifact in the right STN. Contrast-enhanced MR images showed no additional findings. The caudate and putamen appeared normal in all sequences of MR images. Hemiballism was improved with clonazepam (6 mg/day) after 14 days. ...
