Secondary tics: Etiology, presentation, and management

Tics are involuntary or semivoluntary, abrupt, brief, nonrhythmic, recurrent movements or sounds. Tourette syndrome (TS) is the most common cause of tics; however, several other disorders have been associated with tics and tic-like movements. Etiologies of secondary tic syndromes and disorders (STS) include hereditary, drug-induced (including tardive), toxins, traumatic, cerebrovascular, infectious, parainfectious, autoimmune, functional disorders, and others. Age at onset after 18 years, lack of comorbid attention-deficit/hyperactivity disorder, obsessive-compulsive disorder, and no family history of tics are considered typical features of STS. Atypical neurologic manifestations such as additional movement disorders, seizures, decreased level of consciousness, and neurologic deficits, temporally related to some triggering event, such as brain trauma, stroke, or drug exposure, should raise suspicion of STS. These patients usually show a more restricted body distribution, less severe and less complex tics compared with patients with TS. Some tics, typically observed in TS, such as eye-blinking, facial grimacing, and complex motor and phonic tics that are preceded by a premonitory urge may not be present in STS. However, there is a substantial overlap of features between patients with TS and STS. Pharmacologic treatment of STS is similar to TS. Additionally, these patients may require specific treatment, such as anticonvulsants, antibiotics, immunotherapy, or drug-discontinuation. Therefore, prompt recognition and early treatment intervention of STS is imperative for a favorable outcome.