LAUSR

A 65-year-old woman with hypertension, hyperlipidemia, ascending aortic aneurysm repair and valve replacement, and periprocedural atrial fibrillation (not on anticoagulation) presented with sudden-onset imbalance. The patient was on a treadmill when she experienced acute gait instability without vertigo. She held onto the bars to stay midline; otherwise, she leaned rightward. Examination revealed past-pointing and ataxic gait without dysarthria or nystagmus. Brain MRI demonstrated small superior vermis infarct. MRA revealed no significant stenosis. CTA of the chest showed an increase in known aortic pseudoaneurysm (Figure). Such pseudoaneurysms are not known to form thrombi or become embolic sources; she continued aspirin without anticoagulation. Gait instability and vertigo are common presenting signs of cerebellar infarction1; isolated lateropulsion may be seen in lesions involving the vermis.2