Right Lateral Mediullary Syndrome (Wallenberg Syndrome) With Lateropulsion and Ocular Tilt Reaction

A 55-year old man presented with acute onset right-sided facial numbness, left-sided body numbness, vertigo, right ptosis, and binocular vertical diplopia. External examination showed right ptosis and miosis indicating a right Horner syndrome (Figure 1). He had gaze-evoked nystagmus only on right gaze, hypermetric saccades to the right, hypometric saccades to the left, and a left hypertropia that improved with right head tilt and worsened with left head tilt. The patient's eyes were deviated to the right during eyelid closure, demonstrating ocular lateropulsion (Video 1). Dilated fundus examination revealed excyclotorsion of the right eye and incyclotorsion of the left eye (Figure 3). Axial MRI of the brain showed a hyperintensity on DWI in the right lateral medulla and a corresponding hypointensity on the ADC map consistent with an acute infarction of the right lateral medulla (Figure 4). The structures affected by the infarction in the lateral medulla include the vestibular nuclei, inferior cerebellar peduncle, descending sympathetic pathways, and lateral spinothalamic tract (Figure 5). There are prominent neuro-ophthalmic findings in a patient with Wallenberg syndrome and is usually caused by compromise of the posterior inferior cerebellar artery (PICA) leading to infarction. [[Figure 1. External examination showing right ptosis and miosis indicating a right Horner syndrome. Figure 2. Axial T1 MRI of the brain post-contrast shows the patient's eyes deviated to the right, demonstrating ocular lateropulsion, which is a compelling sensation of being pulled towards one side (the side of the lesion in Wallenberg syndrome) Figure 3. Fundus photos demonstrated incyclotorsion of the right eye and excylotorsion of the left eye. Figure 4. Axial MRI of the brain showed a hyperintensity on DWI in the right lateral medulla and a corresponding hypointensity on the ADC map consistent with an acute infarction of the right lateral medulla. Figure 5. The structures affected by the infarction in the right lateral medulla include the vestibular nuclei, inferior cerebellar peduncle, descending sympathetic pathways, and lateral spinothalamic tract. Figure 6. Lateral medullary syndrome is usually caused by compromise of the posterior inferior cerebellar artery (PICA) leading to infarction.]]