Transient symptomatic worsening by atropine in opsoclonus-myoclonus syndrome.

Opsoclonus-myoclonus syndrome (OMS) is characterized by abnormal eye and systemic involuntary movements, as well as cerebellar ataxia. Some sedatives and anesthetics worsen movements associated with OMS, while there is no known report of a negative effect of atropine. We report on sedation in two patients with OMS. Involuntary movements were transiently worsened after using atropine with midazolam or thiamylal in both, but were not seen when atropine was not used. We speculated that atropine has the potential to exacerbate involuntary movements in OMS due to vulnerability to this agent via unknown mechanisms.