When Time Matters: Diagnosis of Percheron Stroke.

The artery of Percheron (AOP) is a rare vascular variant that can cause bilateral paramedian thalamic infarctions when occluded. Due to its atypical clinical presentation and subtle imaging findings, this condition often leads to significant diagnostic challenges. The timely recognition of this condition is critical to implementing appropriate management strategies and improving patient outcomes. We report the case of a 76-year-old man with no prior medical history who presented to the emergency department with a sudden onset of impaired consciousness and vertical gaze palsy. On arrival, the patient was in a state of sleep-like coma. This clinical presentation, combined with the sudden onset of symptoms, was highly suggestive of an AOP infarction. The initial CT findings were unremarkable. Intravenous thrombolysis was administered due to clinical suspicion. The patient demonstrated rapid clinical improvement and regained consciousness in several hours. A follow-up CT scan 24 hours later confirmed bilateral paramedian thalamic infarction, establishing the diagnosis. Although the patient experienced moderate residual cognitive impairment and mild vertical gaze paresis, he regained functional independence within six months. AOP infarction is a rare but serious condition that can present with various symptoms. Its diagnosis can be challenging due to the nonspecific clinical presentation and limitations of conventional imaging techniques in the acute phase, especially in our local context. Early diagnosis and timely intervention, such as intravenous thrombolysis, are crucial to improving functional outcomes.