Diagnostic Challenges in Acute Basilar Artery Occlusion Successfully Treated With Mechanical Thrombectomy: A Case Report.

Posterior circulation strokes are uncommon but are associated with high morbidity and mortality. We report the case of an 80-year-old woman with untreated hypertension who presented with sudden-onset vertigo, vomiting, gait instability, dysmetria, altered mental status, and oculomotor abnormalities without clear focal motor deficits. Initial noncontrast brain computed tomography showed no acute hemorrhage, while CT angiography demonstrated the absence of contrast opacification of the basilar artery, consistent with acute basilar artery occlusion (BAO). Baseline imaging suggested limited established infarction. The patient underwent urgent digital subtraction angiography followed by mechanical thrombectomy via the left vertebral artery, achieving complete recanalization. The time from symptom onset to successful reperfusion was nine hours. Neurological recovery was rapid, with full return to baseline functional status within 24 hours (modified Rankin Scale (mRS) score: 0). Follow-up brain magnetic resonance imaging, including diffusion-weighted imaging, demonstrated small ischemic lesions consistent with lacunar infarcts without evidence of large territorial infarction or hemorrhagic transformation. This case highlights the diagnostic challenges of posterior circulation stroke and emphasizes that early vascular imaging and timely mechanical thrombectomy can result in favorable outcomes, even in elderly patients with acute BAO.