Posterior Circulation Stroke as a Time-Sensitive Systems Failure: A Case of Basilar Artery Occlusion With Multisystem Complications.

Posterior circulation stroke, particularly basilar artery occlusion, represents a neurologic emergency with high morbidity and mortality, often complicated by diagnostic ambiguity and rapid systemic deterioration. We present the case of a 56-year-old male with multiple vascular risk factors who presented with acute altered mental status, dysarthria, and focal neurologic deficits. Initial evaluation considered a broad differential diagnosis, including intracranial hemorrhage, seizure, and metabolic derangements; however, rapid multimodal assessment excluded these etiologies and supported an acute ischemic process. Advanced imaging demonstrated high-grade basilar artery stenosis with a large perfusion mismatch, indicating a substantial volume of salvageable tissue despite minimal early infarction. Based on these findings, intravenous thrombolysis was administered within the therapeutic window, followed by transfer for neurointerventional evaluation and successful endovascular reperfusion. The clinical course was complicated by aspiration pneumonia, acute kidney injury, and metabolic instability, reflecting the systemic impact of posterior circulation ischemia. Magnetic resonance imaging confirmed an acute cerebellar infarction without hemorrhagic transformation. With coordinated multidisciplinary care, the patient demonstrated gradual neurologic improvement and was discharged in stable condition with residual deficits. This case supports a systems-based conceptual framework for posterior circulation stroke as a time-sensitive process, in which outcomes are influenced not only by timely reperfusion but also by early diagnostic clarity and proactive management of secondary physiologic complications.