Reversible hemichorea associated with extracranial carotid artery stenosis.

Hemichorea associated with carotid artery occlusive disease is extremely rare. It has been recently suggested that carotid artery stenosis should be considered in the differential diagnosis of chorea, even in the absence of a preceding stroke or transient ischemic attack. Although the pathophysiology of this condition is still under discussion, some reports suggest that impaired cerebral blood flow in the basal ganglia is a key contributing factor. We herein report a case of hemichorea related to severe stenosis of the left internal carotid artery with no basal ganglia lesions on brain MRI. After carotid revascularization, hemichorea gradually subsided and reversible left thalamic and putaminal hypoperfusion were demonstrated by functional neuroimaging. This case report supports the hypothesis about the central role of hemodynamic ischemia in the pathophysiology of hemichorea associated with carotid artery stenosis, and highlights the importance of vascular imaging studies for the early identification of carotid disease in patients with chorea, even in the absence of other clinical signs.