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Tourette syndrome (TS) is a movement disorder most commonly seen in school-age children; a childhood-onset neurobehavioral disorder characterized by the presence of multiple motor and at least one phonic tic (see “Physical Exam”)
- Tics are sudden, brief, repetitive, stereotyped motor movements (motor tics) or sounds (phonic tics) produced by moving air through the nose, mouth, or throat.
- Tics tend to occur in bouts.
- Tics can be simple or complex.
- Motor tics precede vocal tics.
- Simple tics precede complex tics.
- Tics often are preceded by sensory symptoms, especially a compulsion to move.
- Patients are able to suppress their tics, but voluntary suppression is associated with an inner tension that results in more forceful tics when suppression ceases.
- System(s) affected: nervous
- The onset occurs before 18 years of age.
- Predominant age
- Average age of onset: 7 years (3 to 8 years)
- Tic severity is greatest at ages 7 to 12 years.
- 96% present by age 11 years
- Of children with TS, 50% will experience complete resolution of symptoms by age 18 years (based on self-reporting).
- Predominant sex: male > female (3:1)
- Predominant race/ethnicity: clinically heterogeneous disorder, but non-Hispanic whites (2:1) compared with Hispanics and/or blacks
0.77% overall in children
- 1.06% in boys
- 0.25% in girls
Etiology and Pathophysiology
Abnormalities of dopamine neurotransmission and receptor hypersensitivity, most likely in the ventral striatum, play a primary role in the pathophysiology.
- Abnormality of basal ganglia development
- Thought to result from a complex interaction between social, environmental, and multiple genetic abnormalities
- Mechanism is uncertain; may involve dysfunction of basal ganglia–thalamocortical circuits, likely involving decreased inhibitory output from the basal ganglia, which results in an imbalance of inhibition and excitation in the motor cortex
- Controversial pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS)
- TS/OCD cases linked to immunologic response to previous group A β-hemolytic Streptococcus (GABHS)
- Thought to be linked to 10% of all TS cases
- Five criteria
- Presence of tic disorder and/or OCD
- Prepubertal onset of neuropsychosis
- History of sudden onset of symptoms and/or episodic course with abrupt symptom exacerbation, interspersed with periods of partial/complete remission
- Evidence of a temporal association between onset/exacerbation of symptoms and a prior streptococcal infection
- Adventitious movements during symptom exacerbation (e.g., motor hyperactivity)
- Predisposition: frequent familial history of tic disorders and OCD
- Precise pattern of transmission and genetic origin unknown. Recent studies suggest polygenic inheritance with evidence for a locus on chromosome 17q; sequence variants in SLITRK1 gene on chromosome 13q also are associated with TS.
- Higher concordance in monozygotic compared with dizygotic twins; wide range of phenotypes
- Risk of TS among relatives: 9.8–15%
- First-degree relatives of individuals with TS have a 10- to 100-fold increased risk of developing TS.
- Low birth weight, maternal stress during pregnancy, severe nausea and vomiting in 1st trimester
Commonly Associated Conditions
- OCD (28–67%)
- ADHD (50–60%)
- Conduct disorder
- Depression/anxiety including phobias, panic attacks, and stuttering
- Learning disabilities (23%)
- Impairments of visual perception, sleep disorders, restless leg syndrome, and migraine headaches