Smoking Induced Worsening of Myoclonic Dystonia due to Haloperidol: A Case Report

Acute dystonia is a side effect of antipsychotic medication, and appears shortly after beginning treatment. The movement disorder is characterized by sustained muscle contractions that are typically slow, but rapid dystonia referred to as myoclonic dystonia has also been described. Cranial, pharyngeal and cervical muscles are generally affected causing fixation of the jaw, retrocollis, torticollis or opisthotonic posturing. Acute laryngeal dystonia (laryngospasm) with dysphonia has rarely been reported. Although known for six decades, the mechanism underlying acute dystonia is not clearly understood. It has been reported to be associated with striatal dopaminergic and cholinergic dysfunction due to the D2 receptor blockade of antipsychotics in the basal ganglia. We discuss a patient with haloperidol-induced atypical myoclonic dystonia that got worse with smoking together with the role of the cholinergic system in acute dystonia in this case report.