Artery of Percheron Syndrome From a Possible Paradoxical Embolus in the Intensive Care Unit: An Easily Missed Diagnosis in Intubated Patients

The following report describes a case of Artery of Percheron syndrome (AOP syndrome), an infarction involving a rare anatomic arterial variant that provides bilateral blood supply to the medial thalamic regions of the brain. This case occurred in a 55-year-old male patient admitted to the intensive care unit (ICU) with reduced consciousness. The patient required intubation and invasive ventilation in the ICU and was initially thought to be suffering from a drug overdose following a normal CT brain report. On extubation, focal neurological findings on bedside clinical examination prompted an MRI scan, which revealed bilateral thalamic and midbrain infarcts characteristic of Artery of Percheron syndrome. Following commencement of dual antiplatelet therapy, a subsequent transthoracic echocardiogram revealed a patent foramen ovale, which was later confirmed on transesophageal echocardiography, raising the possibility of a paradoxical embolus as the underlying cause of the Artery of Percheron occlusion. This case aims to raise awareness of this condition as a potential cause of loss of consciousness, demonstrate the diagnostic difficulties associated with it, and highlight the importance of neurological examination and a high index of suspicion in cases of reduced consciousness despite a normal CT brain.