Wilson Disease Presenting as Opsoclonus-Myoclonus Syndrome

A 31-year-old previously healthy man presented with an insidious 3-month history of anxiety and agoraphobia, and recent upper limb action tremor and balance difficulties. On examination, he was very apathetic and almost mute. Smooth pursuit and saccadic ocular movements were intact, but he had bouts of ocular flutter. Mini-myoclonus in both hands and negative myoclonus in all four limbs interfered with smooth movements. He was slightly dysarthric, had mild dysmetria, intention tremor, dysdiadochokinesia, and difficulties with tandem gait.