Gradual Onset Lateral Medullary Infarction with Ipsipulsion and Asymmetric Saccades: Expanding the Clinical Spectrum of Posterior Inferior Cerebellar Artery (PICA) Stroke

Background Lateral medullary infarction (Wallenberg’s syndrome) is a classical posterior circulation stroke, typically presenting with dissociated sensory loss and lower cranial nerve involvement. Ocular motor abnormalities such as ipsipulsion and asymmetric saccadic gain are rarely reported but may provide important diagnostic clues.   Case Presentation We describe a 45-year-old Asian woman with diabetes, hypertension, and dyslipidemia who presented with acute-onset dysphagia, vomiting, and right-sided facial numbness, which progressed over 24 hours. Neurological examination revealed dissociated sensory loss, impaired gag reflex with uvular deviation, and nasal speech. Ocular motor findings included right-beating nystagmus, ipsilateral gaze deviation with ocular ipsipulsion, hypermetric saccades to the right, and hypometric saccades to the left. Magnetic resonance imaging confirmed an infarction of the right lateral medulla. CT angiography and echocardiography excluded arterial dissection and cardioembolism. She was treated with dual antiplatelet therapy, statins, and optimization of vascular risk factors.   Conclusion This case highlights three uncommon but clinically significant features of lateral medullary infarction: gradual onset with progressive worsening, ocular ipsipulsion, and asymmetric saccadic gain. Recognition of these atypical findings may expand the clinical spectrum of posterior circulation stroke and facilitate timely diagnosis.