Neuroradiological Evolution of Glycaemic Hemichorea-Hemiballism and the Possible Role of Brain Hypoperfusion

BACKGROUND: Lateralized involuntary movements consistent with hemichorea-hemiballism (HCHB) may appear following the development of contralateral haemorrhagic or ischaemic lesions of the basal ganglia, particularly the striatum (caudate nucleus and putamen). This condition is called vascular HCHB, but the same symptoms can be caused by a completely different striatal lesion. Glycaemic HCHB may occur in patients with uncontrolled hyperglycaemia: basal ganglia hyperdensity is seen on brain CT, while increased T1 signal intensity and reduced susceptibility-weighted imaging (SWI) and gradient-echo sequences (T2*-GRE) are detected on MRI. CASE DESCRIPTION: An 83-year-old man with multiple vascular risk factors and uncontrolled chronic hyperglycaemia was admitted for ischaemic stroke presenting with dysarthria and mild left hemiparesis. No involuntary movements were reported at admission. The emergent brain CT scan was negative for vascular acute lesions, while a mild bilateral hyperdensity of the striata was detectable. Involuntary movements on the left side of the body, consistent with HCHB, appeared 27 days later. The alterations on brain CT completely disappeared after 3 months. On brain MRI, the T1 signal alterations resolved after 10 months, while SWI and T2*-GRE sequences showed persisting alterations after 2 years. DISCUSSION: Detailed brain imaging demonstrated evolution of striatal alterations of glycaemic HCHB before the appearance of involuntary movements and during the following 2 years. The association between ischaemic stroke and glycaemic HCHB favours the hypothesis that chronic hyperglycaemia more likely determines striatal alterations and the clinical picture of HCHB when vascular hypoperfusion also occurs. LEARNING POINTS: Hemichorea-hemiballism (HCHB) may appear in patients with uncontrolled hyperglycaemia accompanied by typical neuroradiological features consisting of striatal alterations detectable on brain CT and MRI, often bilaterally. Unusually, striatal alterations can be detected before the appearance of involuntary movements and are fully reversible on brain CT and T1-MRI sequences. Brain hypoperfusion may facilitate the appearance of typical HCHB in patients with chronic hyperglycaemia.