[Tic syndrome].

Abstract

A tic is an involuntary, sudden, rapid, recurrent, nonrrhythmic, stereotyped, motor movement or vocalization. This paper reviews clinical, pathophysiological, epidemiological and treatment issues of tic disorders. The clinical presentation of tic disorders with simple and complex motor or vocal tics is reviewed in detail. The most common psychiatric comorbid conditions, such as personality disorder (PD), Obsessive-Compulsive Disorder (OCD), Self-Destructive Behavior (SDB) and Attention Deficit Hyperactivity Disorder (ADHD) are presented too. All forms of tics may be exacerbated by anger or stress, but they are usually markedly diminished during sleep. Premonitory feelings or "sensory experiences", which are distinct from the actual motor or phonic tics and precede the tics, occur in over 80% of tic-patients and in 95% of patients with Gilles de la Tourette Syndrome (GTS). The American Psychiatric Association recognizes three types of tic disorders on the basis of clinical criteria: Transient Tic Disorder, Chronic Motor or Vocal Tic Disorder and GTS. The diagnostic criteria for these types are described. According to epidemiological data, up to 10% of children have at least somewhere a transient tic disorder. The onset of tics, whether simple or multiple, occurs at approximately 7 years of age. The accepted prevalence figure for GTS is 0.05-3%. Although tics can appear as the result of brain injury, Huntington chorea or encephalitis, they are most commonly idiopathic. Genetic factors appear to be present in many but not in all cases of tic disorders. Autosomal dominant, sex-linked models or semirecessive-semidominant-oligogenic models have been considered. Based on the review of the literature we believe that tic disorders are related to altered neurotransmitter function within the CNS, especially that the functional abnormality is somehow related to dopaminergic mechanism. Several authors have recently investigated the possible role of autoimmune response to streptococcal infection in the pathogenesis of tics. The differential diagnosis of tics is reviewed in detail. Above all tics represent a social disability. The ability to tolerate tics varies greatly from one individual to another, and the need for treatment is better defined by the patient than by the physician. Mild cases do not need be treated. Ideally, management should be multidisciplinary and can range from educative to supportive means or to intricate pharmacological interventions. The major form of treatment of the motor or vocal symptoms continues to be based on high-potency "typical" neuroleptics (tiaprid, pimozide, haloperidol), which induce a wide range of potentially serious side effects. In everyday practice we prefer to start with an "atypical" neuroleptic drug--for example, olanzapin (5-10 mg/day), risperidone or clozapine. Other drugs, such as clonidin or pergolid are widely used but their efficiency is still questionable. SSRIs (sertaline, citalopram, fluoxetin, fluvoxamine) or other antidepressants (clomipramine) have been used in treatment of psychiatric comorbid conditions, too. Botulinum toxin injections have proved useful in tics, targeting at the symptoms of blepharospasm, in neck and facial muscles.