(DRG) Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, Emergency Medicine, and Medicine, The Johns Hopkins School of Medicine, Baltimore, Maryland
Subject
Ocular flutter; Upbeat nystagmus
Description
This patient was diagnosed with a cerebellar pilocytic astrocytoma, and underwent surgical resection and radiation therapy. Oscillopsia developed, which was both horizontal and transient (due to ocular flutter) as well as vertical and constant (due to upbeat nystagmus). Although the flutter (back-to-back saccades) occurred spontaneously, it could also be triggered by convergence or following saccades. There was encephalomalacia of the caudal cerebellum and dorsal brainstem (dorsal medullary involvement would explain the upbeat nystagmus), although the origin of the ocular flutter was less clear, but presumably involving the saccadic pathways connecting inferior olive to contralateral dorsal vermis to ipsilateral fastigial nucleus to contralateral paramedian pontine reticular formation and excitatory (and inhibitory) burst neurons.
