Opsoclonus Myoclonus Syndrome associated with GQ1b Antibodies

Abstract

Opsoclonus myoclonus syndrome (OMS) is a rare disorder characterized by involuntary, multidirectional, chaotic saccades; head, limb, and trunk action myoclonus; and other associated features including cerebellar ataxia, encephalopathy, postural tremor, and sleep and behavioral disruption. 1 OMS can occur as a paraneoplastic or nonparaneoplastic syndrome. In both cases, an autoimmune pathophysiology has been proposed. 1,2 We report a 37-year-old man who developed an upper respiratory tract infection. Five days later, he developed paroxysms of blurred vision and oscillopsia. He had prominent neck myoclonus that ceased when supine but was provoked by sitting up, standing, or walking. Truncal instability was present, resulting in an inability to walk unassisted. Neurological examination (see Video) revealed eye movements with periodic, rapid, conjugated chaotic ocular oscillations that were independent of eye position and occurred during fixation, regardless of gaze direction, with eyes open or closed. Disabling ataxia of the trunk, limbs, and gait was present with stimulus-sensitive myoclonus. Cerebrospinal fluid (CSF) analysis showed lymphocytic pleocytosis and unmatched oligoclonal bands. Full blood count, serum chemistry, thyroid profile, cardiolipin, lupus anticoagulant, and dsDNA antibodies, Yo, Hu, Ri antibodies, brain CT and MRI, and