ABSTRACT NUMBER: ESOC2026A1991 THE TIP THAT TOPPLED: AN UNCOMMON PRESENTATION OF BASILAR ARTERY TIP OCCLUSION

Abstract Background and aims Basilar artery tip occlusion (BATO) is a rare and complex cause of posterior circulation stroke, characterised by a broad and often misleading clinical spectrum. Unlike proximal basilar artery occlusion, distal tip occlusion can present without coma or classic brainstem symptoms and signs leading to delays in diagnosis. This report highlights the diagnostic challenges in a case of BATO with posterior circulation infarction. Methods We present the case of a 58-year-old female who presented to the emergency department following a fall, with symptoms including vomiting, confusion, agitation, and a low GCS of 11/15. Neurological examination revealed aphasia and left limb weakness. Non-contrast CT brain and CT angiography were conducted, followed by further neuroimaging to assess the extent of the vascular injury and associated infarction. Results Initial CT angiography of the aortic arch and carotid arteries revealed basilar artery occlusion extending from the mid-basilar segment to the basilar tip. MRI brain confirmed moderate pontine infarcts bilaterally, with smaller infarctions in the bilateral cerebellum and left occipital region. Despite significant brainstem involvement, the patient did not exhibit coma or typical cranial nerve deficits. Instead, her clinical presentation was dominated by aphasia and behavioural disturbances, which mimicked anterior circulation stroke. She underwent thrombectomy with gradual improvement clinically. Conclusions This case highlights the heterogeneous clinical and radiological presentations of BATO. Even with significant posterior circulation infarction, patients may present with preserved consciousness, agitation, and aphasia rather than the expected brainstem signs. Early recognition of these atypical presentations is crucial to avoid diagnostic delays and ensure timely intervention. Conflict of interest All authors: nothing to disclose Figure 1 - belongs to Results