PT - JOURNAL ARTICLE AU - Clare Anderson AU - Richard O'Brien TI - Occlusion of the artery of Percheron: an unusual cause of bilateral stroke AID - 10.1136/bcr-2012-007205 DP - 2012 Nov 19 TA - BMJ Case Reports PG - bcr2012007205 VI - 2012 4099 - http://casereports.bmj.com/content/2012/bcr-2012-007205.short 4100 - http://casereports.bmj.com/content/2012/bcr-2012-007205.full AB - The artery of Percheron is a rare anatomical variant whereby a single vessel arising from the proximal segment of one posterior cerebral artery supplies both medial thalami. This is a rare example of a single arterial supply to brain structures on both sides of the midline. Occlusion of the artery of Percheron results in bilateral medial thalamic infarction, which is manifest clinically as gaze paresis, cognitive disturbance and altered consciousness. The presentation can mimic subarachnoid haemorrhage, drug intoxication, encephalitis and other inflammatory or infective conditions. The presentation is similar to the ‘top of the basilar syndrome’ and early recognition should prompt further investigation for underlying stroke aetiologies and consideration can be given to thrombolysis if vascular occlusion can be confirmed.