Temporomandibular joint dislocation due to atypical antipsychotic-induced acute dystonia: a case report.

Abstract

Dystonia is a movement disorder that causes sustained muscle contractions, repetitive twisting movements, and abnormal postures of the trunk, neck, face, arms or legs [Fahn et al. 1987]. It may be focal, segmental (multifocal), or generalized and may also be primary or secondary based on their etiology. It may manifest as oculogyric crisis, deviation of eyes in all directions, protrusion of tongue, trismus, lock jaw, torticolis, laryngeal spasm, difficulty in speaking, facial grimacing, opisthotonus, lordosis or scoliosis and tortipelvic crisis. Drug-induced dystonia are secondary dystonias which occur commonly with drugs with antidopaminergic effects such as antipsychotics and metoclopramide [Ropper and Samuels, 2009; Fadare and Owolabi, 2009]. They reportedly arise from a drug-induced alteration of dopaminergic–cholinergic balance in the nigrostriatum (i.e. basal ganglia). Most drugs produce dystonic reactions by nigrostriatal dopamine D2 receptor blockade, which leads to an excess of striatal cholinergic output. High-potency D2 receptor antagonists are most likely to produce an acute dystonic reaction [Marsden and Jenner, 1980]. Agents that balance dopamine blockade with muscarinic M1 receptor blockade, such as atypical antipsychotics, are less likely to cause dystonic reactions [Marsden and Jenner, 1980; Volkow et al. 1998]. The incidence of acute dystonic reactions varies according to individual susceptibility, drug identity and dose of the drug. Increased age may carry less risk for the development of dystonia because of diminished numbers of D2 receptors. It occurs commonly to young males who are naive to antidopaminergic drugs [Volkow et al. 1998]. Oromandibular dystonia is one of the focal dystonias, which can be presented as jaw clenching, jaw opening or jaw deviation and leads to impaired speech and swallowing [Eken et al. 2009]. At times, oromandibular dystonia is so severe that it can cause temporomandibular joint (TMJ) dislocation. So far, few case reports have been published about TMJ dislocation due to antipsychotic medications [Ibrahim and Brooks, 1996]. Among antipsychotic-induced TMJ dislocation, case reports were mainly for high-potency first-generation antipsychotics such as haloperidol [Eken et al. 2009; Ibrahim and Brooks, 1996; Zakariaei et al. 2012]. It has been proposed that drugs such as risperidone and amisulpride which block specific receptors of serotonin (the S-HT2 receptors) and dopamine (the D2 receptors) are less likely to cause these effects [Owens, 1994]. Therefore, the present paper reports a case of oromandibular dystonia with TMJ dislocation with atypical antipsychotics such as risperidone and amisulpride.