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For further information, see CMDT Part 26-14: Movement Disorders

KEY FEATURES

Essentials of Diagnosis

  • Multiple motor and phonic tics

  • Symptoms begin before age 18 years

  • Tics occur frequently for at least 1 year

  • Tics vary in number, frequency, and nature over time

General Considerations

  • The diagnosis of the disorder is often delayed for years, the tics being interpreted as psychiatric illness or some other form of abnormal movement

  • Patients are thus often subjected to unnecessary treatment before the disorder is recognized

Demographics

  • Tics are noted first in childhood, generally between the ages of 2 and 15

  • Genetic studies are ongoing

    • Gene association studies have extensively investigated dopamine and serotonin system genes, but there have been no consistent results

    • Genome-wide association studies have implicated several genetic loci on Slit and Trk-like 1 (SLITRK1) and histidine decarboxylase (HDC) genes; however, larger study cohorts are needed to confirm this

    • Whole genome/exome sequencing has identified several novel pathogenic variants in various genes in patients with Tourette syndrome but more studies are needed to reveal the exact underlying mechanisms

CLINICAL FINDINGS

Symptoms and Signs

  • Motor tics

    • Initial manifestation in 80% of cases

    • Most commonly involve the face, head, and shoulders, with movements such as sniffing, blinking, frowning, shoulder shrugging, and head thrusting

  • Phonic tics

    • Initial symptoms in 20% of cases

    • Commonly consist of grunts, barks, hisses, throat clearing, coughs, verbal utterances including coprolalia (obscene speech)

  • A combination of different motor and phonic tics ultimately develop in all patients

  • Echolalia (repetition of the speech of others)

  • Echopraxia (imitation of others' movements)

  • Palilalia (repetition of words or phrases)

  • Some tics may be self-mutilating in nature

    • Nail biting

    • Hairpulling

    • Biting of the lips or tongue

  • Obsessive-compulsive disorder (OCD) and attention deficit hyperactivity disorder are commonly associated and may be more disabling than the tics themselves

  • In addition to OCD, psychiatric disturbances may occur because of the associated cosmetic and social embarrassment

Differential Diagnosis

  • Wilson disease

DIAGNOSIS

Diagnostic Procedures

  • Examination usually reveals no abnormalities other than the tics

TREATMENT

Medications

  • α-Adrenergic agonists are first-line therapies because of favorable side-effect profile compared with typical antipsychotics

    • Clonidine (start 0.05 mg orally at bedtime, titrating to 0.3–0.4 mg orally daily, divided three to four times per day)

    • Guanfacine (start 0.5 mg orally at bedtime, titrating to a maximum of 3–4 mg orally daily, divided two times per day)

  • Atypical antipsychotic risperidone (1–6 mg daily orally) is more effective than placebo in controlling tics and more effective than pimozide in improving symptoms of comorbid OCD and may be tried before the typical antipsychotic agents

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