Hypoglycemic Encephalopathy Manifesting with Cortical Hemichorea-Hemiballismus Syndrome: A Case Report

Abstract

Hyper-/hypoglycemic states are rare but well-established causes of hyperkinetic movements, including chorea and ballismus, usually associated with brain lesions in the basal ganglia. We report a case of hemichorea-hemiballismus (HCHB) syndrome that developed after a severe hypoglycemic episode in a 71-year-old man with poorly controlled type 2 diabetes mellitus. Uncommonly, brain MRI showed contralateral cortical-subcortical T2 and T2-FLAIR-hyperintense frontoparietal lesions, with cingulate gyrus involved, while the basal ganglia were unaffected. In patients with hypoglycemic encephalopathy associated with cortical lesions, the long-term prognosis is usually poor. Nevertheless, in our patient, the dyskinesias and the cerebral lesions progressively regressed by achieving good glycemic control. After four and 12 months, the patient's neurological examination was normal. To our knowledge, this is the first evidence of hypoglycemic etiology of cortical HCHB syndrome, supporting recent theories that cortical circuitries may independently contribute to the pathogenesis of chorea and ballismus. This is also the first report of cingulate gyrus involvement in hypoglycemic encephalopathy. Finally, this case may indicate that a subset of patients with cortical lesions due to hypoglycemia could present a good clinical outcome, likely depending on the size of the lesions and the duration and severity of the hypoglycemic episode.

Keywords: Hemiballismus; Hemichorea; Hemichorea-hemiballismus syndrome; Hypoglycemia; Hypoglycemic encephalopathy.

Fig. 1.

Serial patient’s brain MRIs are shown in the picture. Respectively, T2-FLAIR (first two pictures), DWI, and ADC sequences are reported. In the first MRI (a), a cortical-subcortical left frontal lesion, involving the cingulate gyrus, and an ipsilateral paramedian, parietal cortical lesion are evident. Both lesions are hyperintense on T2, T2-FLAIR, and DWI sequences, while ADC is mildly decreased. No lesions were detected in the basal ganglia on T1, T2-FLAIR, DWI, and ADC sequences (b). After 6 days (c), the left parietal T2-FLAIR hyperintensity was clearly reduced, while the frontal one was just slightly diminished. DWI restrictions in both areas were decreased, especially in the parietal location. ADC was normal. T1 sequences were slightly hypointense. The follow-up MRI imaging at 4 months (d) showed complete regression of the abnormalities.

Fig. 2.

Patient’s clinical course during the hospitalization and the rehabilitation facility.