Neuro-Ophthalmologic Emergencies in Movement Disorders

Eye movement abnormalities due to urgent or emergent etiologies in the field of movement disorders include acute/subacute onset supranuclear saccadic gaze palsies, ocular flutter and opsoclonus, various types of nystagmus, and oculogyric crisis. Supranuclear saccadic gaze palsies, from failure of brainstem supranuclear saccadic burst neurons, cause slowing of saccades (horizontally and/or vertically) with or without range of motion limitation of eye movements. Acute/subacute causes of saccadic gaze palsies include vascular, neoplastic/paraneoplastic, infectious, and inflammatory etiologies. Ocular flutter and opsoclonus are erratic bursts of high frequency, rapid saccades that oscillate about the midline of the visual axis with no intersaccadic interval. Flutter occurs only in the horizontal plane, while opsoclonus occurs in all trajectories. Ocular flutter and opsoclonus typically occur either in infectious/para-infectious brainstem encephalitis or paraneoplastic/autoimmune disease. Nystagmus is a rhythmic biphasic oscillation of the eyes, initiated by a slow drift of the eyes. Downbeat nystagmus may occur acutely or subacutely from ischemic or paraneoplastic cerebellar disorders. Upbeat nystagmus is common in Wernicke encephalopathy and may occur from a brainstem stroke. Pendular nystagmus from oculopalatal myoclonus is not an emergency, but may be mistaken for a recurrent brainstem stroke. Oculogyric crisis is an acute dystonic reaction of extraocular muscles with a conjugate deviation of the eyes, typically upward. Oculogyric crises are most commonly acute or tardive reactions to neuroleptics, although other etiologies exist.