Artery Of Percheron Infarction: A Great Mimicker

The thalamus is a deep structure located in the diencephalon, whose arterial blood supply is mainly from four branches of posterior cerebral artery. The artery of percheron (AOP) is an infrequent variation of thalamic perfusion, occlusion of which presents with a heterogenous, atypical list of symptoms without focal signs. This is in contrast to the typical, easily recognizable focal neurology of other ischemic infarcts. Therefore, AOP infarctions may be misdiagnosed, delayed in diagnosis or missed altogether. It is a rare, but vital area of neurology that needs to be studied by clinicians to facilitate an overall care for patients.
We report the case of a 59-year-old lady who presented to us with bilateral complete ptosis with bilateral vertical gaze palsy and nystagmus, whose initial NCCT brain was normal. Subsequent MRI showed bilateral thalamic and midbrain ischemic infarctions in the artery of Percheron distribution. Our case highlights the importance of high degree of suspicion, early diagnosis and role of MRI in the diagnosis when initial CT is normal.