Teaching video neuroimages: excessive grinning in Wilson disease.

A 19-year-old man presented with a 3-month history of excessive grinning. Examination revealed unrestrained grinning and mild symmetric parkinsonism. Wilson disease was suspected and confirmed by the presence of Kayser-Fleischer ring (figure), suggestive brain MRI (figure), low ceruloplasmin, and high urinary copper levels. Wilson disease is a disorder of copper metabolism characterized by hepatic impairment and movement disorders. Typical facial manifestations, although not pathognomonic, include excessive grinning, in which the patient grins to trivial stimuli,1 as demonstrated in this report; sustained open-mouth smile, when a parkinsonian face is associated with a dystonic dropped jaw (sometimes referred to as “vacuous smile”)2; and fixed forced smile, when facial dystonia produces a sustained spasm of risorius and zygomaticus muscles (also referred to as “risus sardonicus”).