Pearls & Oy-sters: Positional vertigo and vertical nystagmus in medulloblastoma: A picture is worth a thousand words.

Pearls c Eye movement abnormalities can be helpful with topical localization. c Vertical nystagmus (downbeat and upbeat nystagmus) is typically caused by posterior fossa lesions. Other causes include medication side effects, vitamin deficiencies, inflammatory and autoimmune/paraneoplastic conditions, and hereditary and degenerative cerebellar ataxias. c Lesions in the posterior fossa such as medulloblastoma may also present with positional vertigo, with similar characteristics to benign paroxysmal positional vertigo. c MRI of the brain with contrast is the imaging of choice in the workup of ataxia and vertical nystagmus.