Artery of Percheron Stroke Causing Sudden Altered Consciousness and Memory Impairment

Introduction The artery of Percheron (AOP) is a rare anatomical variant in which a single artery arising from the posterior cerebral artery (PCA) supplies the bilateral paramedian thalami and rostral midbrain. Infarction of this vascular territory may result in heterogeneous, often nonfocal symptomatology, including altered mentation, vertical gaze palsy, and memory impairment. These atypical features can delay diagnosis and intervention, highlighting the importance of clinical awareness. 1 We report a case of AOP stroke with classic imaging findings and discuss the associated diagnostic challenges and management implications. Methods A 78‐year‐old male with a past medical history of hypertension and peripheral artery disease status post aortofemoral bypass was admitted for bowel ischemia that was initially managed with laparotomy. Two days later, he underwent a mesenteric angiogram with celiac stent placement. The following morning in the surgical trauma intensive care unit, the patient was noted to be at neurological baseline during rounds at 10 AM. Within five minutes, however, he became acutely unresponsive, with a newly dilated right pupil and only minimal withdrawal to painful stimuli. A code stroke was initiated, and Neurology evaluated the patient. His NIH Stroke Scale score was 29. Vital signs and laboratory studies were unremarkable. CTA Head and Neck revealed no large vessel occlusion; CT Perfusion demonstrated no perfusion deficit. Given negative imaging and the recent administration of Oxycodone, opioid overdose was considered. Naloxone was administered without clinical improvement. In the absence of other plausible etiologies for this acute neurological decline, a bilateral thalamic infarct was suspected. After multidisciplinary discussion and a risk‐benefit analysis in the context of a recent laparotomy, the decision was made to administer intravenous Tenecteplase. Results MRI Brain confirmed bilateral thalamic and medial midbrain infarction consistent with an AOP occlusion (Figure). Despite supportive care, the patient demonstrated minimal improvement in mentation two days after Tenecteplase administration. Modafinil was initiated on hospital day three, after which the patient demonstrated improved alertness, followed simple commands, and began eating. Nevertheless, he continued to exhibit cognitive slowing. Conclusion In patients with acute alterations in consciousness not explained by alternative causes, AOP infarction should be considered to enable timely diagnosis and treatment. Our case further suggests that Modafinil may be a useful adjunct to enhance arousal and support neurological recovery in select patients. References 1. Ikramuddin SS, Coburn JA, Ramezani S, Streib C. Artery of Percheron Infarction: Clinical Presentation and Outcomes. Neurol Clin Pract 2024;14(2):e200266. (In eng). DOI: 10.1212/cpj.0000000000200266.