“You know I know”: INO and Nystagmus - A Case Report

The Brachium Pontis (BP), also referred to as the Middle Cerebellar Peduncle, is a paired structure that connects the cerebellum to the pons. The BP, serves as a connector between the cerebellum and cerebral cortex via the pons. As the largest of the three peduncles, it conveys the largest number of fibers and is utilized in the primary cortico-cerebellar-cortical loop, which helps facilitate motor planning. These fibers convey afferent information from the frontal and temporal lobes of the cortex to the posterior lobe of the contralateral cerebellum. Being composed primarily of white matter, the BP lesions are most commonly seen in patients with Multiple Sclerosis. Rarely are lesions to the BP caused by stroke. Because of this, often these patients are initially not appropriately treated due to the concern that they do not match classical presentation of cerebrovascular disease for acute ischemic stroke. We report a case of stroke located in the right BP resulting in nystagmus with fast beating to the left and right lateral rectus palsy and discuss key clinical pearls of treatment in these patients with rare hyperacute presentations.