"Tourette" redirects here. For other uses, see Tourette (disambiguation).

Tourette syndrome
Classification and external resources
Georges Gilles de la Tourette (1857–1904), namesake of Tourette syndrome
ICD-10	F95.2
ICD-9	307.23
OMIM	137580
MedlinePlus	000733
eMedicine	med/3107 neuro/664
MeSH	D005879

Tourette syndrome (also called Tourette's syndrome, Tourette's disorder, Gilles de la Tourette syndrome, GTS or, more commonly, simply Tourette's or TS) is an inherited neuropsychiatric disorder with onset in childhood, characterized by multiple physical (motor) tics and at least one vocal (phonic) tic. These tics characteristically wax and wane, can be suppressed temporarily, and are preceded by a premonitory urge. Tourette's is defined as part of a spectrum of tic disorders, which includes transient and chronic tics.
Tourette's was once considered a rare and bizarre syndrome, most often associated with the exclamation of obscene words or socially inappropriate and derogatory remarks (coprolalia), but this symptom is present in only a small minority of people with Tourette's.^[1] Tourette's is no longer considered a rare condition, but it is not always correctly identified because most cases are mild and the severity of tics decreases for most children as they pass through adolescence. Between 0.4% and 3.8% of children ages 5 to 18 may have Tourette's;^[2] the prevalence of transient and chronic tics in school-age children is higher, with the more common tics of eye blinking, coughing, throat clearing, sniffing, and facial movements. Extreme Tourette's in adulthood is a rarity, and Tourette's does not adversely affect intelligence or life expectancy.
Genetic and environmental factors play a role in the etiology of Tourette's, but the exact causes are unknown. In most cases, medication is unnecessary. There is no effective treatment for every case of tics, but certain medications and therapies can help when their use is warranted. Education is an important part of any treatment plan, and explanation and reassurance alone are often sufficient treatment.^[1][3] Comorbid conditions (co-occurring diagnoses other than Tourette's) such as attention-deficit hyperactivity disorder (ADHD) and obsessive–compulsive disorder (OCD) are present in many patients seen in tertiary specialty clinics. These other conditions often cause more functional impairment to the individual than the tics that are the hallmark of Tourette's, hence it is important to correctly identify comorbid conditions and treat them.^[4]
The eponym was bestowed by Jean-Martin Charcot (1825–1893) on behalf of his resident, Georges Albert Édouard Brutus Gilles de la Tourette (1859–1904), a French physician and neurologist, who published an account of nine patients with Tourette's in 1885.

Classification
Tics are sudden, repetitive, nonrhythmic movements (motor tics) and utterances (phonic tics) that involve discrete muscle groups.^[5] Motor tics are movement-based tics, while phonic tics are involuntary sounds produced by moving air through the nose, mouth, or throat.
Tourette's is one of several tic disorders, which are classified by the Diagnostic and Statistical Manual of Mental Disorders (DSM) as "disorders usually first diagnosed in infancy, childhood, or adolescence" according to type (motor or phonic tics) and duration (transient or chronic). Transient tic disorder consists of multiple motor tics, phonic tics or both, with a duration between four weeks and twelve months. Chronic tic disorder is either single or multiple, motor or phonic tics (but not both), which are present for more than a year.^[5] Tourette's (DSM-IV 307.23) is diagnosed when multiple motor tics, and at least one phonic tic, are present for more than a year.^[6] The fifth version of the DSM (DSM-5), due out in May 2013, is likely to reclassify Tourette's as a neurodevelopmental disorder, and to include additional diagnoses to account for tic disorders due to substance abuse or other general medical conditions.^[7]
Tic disorders are defined only slightly differently by the World Health Organization International Statistical Classification of Diseases and Related Health Problems, ICD-10; code F95.2 is for combined vocal and multiple motor tic disorder [de la Tourette].^[8]
Although Tourette's is the more severe expression of the spectrum of tic disorders,^[9] most cases are mild.^[2] The severity of symptoms varies widely among people with Tourette's, and mild cases may be undetected.^[5]

Characteristics

Examples of motor tics

Tics are movements or sounds "that occur intermittently and unpredictably out of a background of normal motor activity",^[10] having the appearance of "normal behaviors gone wrong".^[11] The tics associated with Tourette's change in number, frequency, severity and anatomical location. Waxing and waning—the ongoing increase and decrease in severity and frequency of tics—occurs differently in each individual. Tics also occur in "bouts of bouts", which vary for each person.^[5]
Coprolalia (the spontaneous utterance of socially objectionable or taboo words or phrases) is the most publicized symptom of Tourette's, but it is not required for a diagnosis of Tourette's and only about 10% of Tourette's patients exhibit it.^[1] Echolalia (repeating the words of others) and palilalia (repeating one's own words) occur in a minority of cases,^[5] while the most common initial motor and vocal tics are, respectively, eye blinking and throat clearing.^[12]
In contrast to the abnormal movements of other movement disorders (for example, choreas, dystonias, myoclonus, and dyskinesias), the tics of Tourette's are temporarily suppressible, nonrhythmic, and often preceded by an unwanted premonitory urge.^[13] Immediately preceding tic onset, most individuals with Tourette's are aware of an urge,^[14][15] similar to the need to sneeze or scratch an itch. Individuals describe the need to tic as a buildup of tension, pressure, or energy^[15][16] which they consciously choose to release, as if they "had to do it"^[17] to relieve the sensation^[15] or until it feels "just right".^[17][18] Examples of the premonitory urge are the feeling of having something in one's throat, or a localized discomfort in the shoulders, leading to the need to clear one's throat or shrug the shoulders. The actual tic may be felt as relieving this tension or sensation, similar to scratching an itch. Another example is blinking to relieve an uncomfortable sensation in the eye. These urges and sensations, preceding the expression of the movement or vocalization as a tic, are referred to as "premonitory sensory phenomena" or premonitory urges. Because of the urges that precede them, tics are described as semi-voluntary or "unvoluntary",^[10] rather than specifically involuntary; they may be experienced as a voluntary, suppressible response to the unwanted premonitory urge.^[1] Published descriptions of the tics of Tourette's identify sensory phenomena as the core symptom of the syndrome, even though they are not included in the diagnostic criteria.^[16][19][20]



Causes

^{Main article: Causes and origins of Tourette syndrome}

^{The exact cause of Tourette's is unknown, but it is well established that both genetic and environmental factors are involved.[28] Genetic epidemiology studies have shown that the overwhelming majority of cases of Tourette's are inherited, although the exact mode of inheritance is not yet known and no gene has been identified.[4][29][30] In other cases, tics are associated with disorders other than Tourette's, a phenomenon known as tourettism.[31]
A person with Tourette's has about a 50% chance of passing the gene(s) to one of his or her children, but Tourette's is a condition of variable expression and incomplete penetrance.[32] Thus, not everyone who inherits the genetic vulnerability will show symptoms; even close family members may show different severities of symptoms, or no symptoms at all. The gene(s) may express as Tourette's, as a milder tic disorder (transient or chronic tics), or as obsessive–compulsive symptoms without tics. Only a minority of the children who inherit the gene(s) have symptoms severe enough to require medical attention.[33] Gender appears to have a role in the expression of the genetic vulnerability: males are more likely than females to express tics.[21]
Non-genetic, environmental, post-infectious, or psychosocial factors—while not causing Tourette's—can influence its severity.[22] Autoimmune processes may affect tic onset and exacerbation in some cases. In 1998, a team at the US National Institute of Mental Health proposed a hypothesis based on observation of 50 children that both obsessive–compulsive disorder (OCD) and tic disorders may arise in a subset of children as a result of a poststreptococcal autoimmune process.[2] Children who meet five diagnostic criteria are classified, according to the hypothesis, as having Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections (PANDAS).[34] This contentious hypothesis is the focus of clinical and laboratory research, but remains unproven.[1][2][35]
Some forms of OCD may be genetically linked to Tourette's.[18][36] A subset of OCD is thought to be etiologically related to Tourette's and may be a different expression of the same factors that are important for the expression of tics.[37] The genetic relationship of ADHD to Tourette syndrome, however, has not been fully established.[27]}

^{Pathophysiology}

^{Brain structures implicated in Tourette syndrome}

^{The exact mechanism affecting the inherited vulnerability to Tourette's has not been established, and the precise etiology is unknown. Tics are believed to result from dysfunction in cortical and subcortical regions, the thalamus, basal ganglia and frontal cortex.[28] Neuroanatomic models implicate failures in circuits connecting the brain's cortex and subcortex,[22] and imaging techniques implicate the basal ganglia and frontal cortex.[29]}

^Diagnosis

^{According to the revised fourth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR), Tourette’s may be diagnosed when a person exhibits both multiple motor and one or more vocal tics (although these do not need to be concurrent) over the period of a year, with no more than three consecutive tic-free months. The previous DSM-IV included a requirement for "marked distress or significant impairment in social, occupational or other important areas of functioning", but this requirement was removed in the most recent update of the manual, in recognition that clinicians see patients who meet all the other criteria for Tourette's, but do not have distress or impairment.[38] The onset must have occurred before the age of 18, and cannot be attributed to the "direct physiological effects of a substance or a general medical condition".[6] Hence, other medical conditions that include tics or tic-like movements—such as autism or other causes of tourettism—must be ruled out before conferring a Tourette's diagnosis.
There are no specific medical or screening tests that can be used in diagnosing Tourette's;[18] it is frequently misdiagnosed or underdiagnosed, partly because of the wide expression of severity, ranging from mild (the majority of cases) or moderate, to severe (the rare, but more widely recognized and publicized cases).[23] Coughing, eye blinking and tics that mimic asthma are commonly misdiagnosed.[1]
The diagnosis is made based on observation of the individual's symptoms and family history,[1] and after ruling out secondary causes of tic disorders.[33] In patients with a typical onset and a family history of tics or obsessive–compulsive disorder, a basic physical and neurological examination may be sufficient.[9]
There is no requirement that other comorbid conditions (such as ADHD or OCD) be present,[1] but if a physician believes that there may be another condition present that could explain tics, tests may be ordered as necessary to rule out that condition. An example of this is when diagnostic confusion between tics and seizure activity exists, which would call for an EEG, or if there are symptoms that indicate an MRI to rule out brain abnormalities.[39] TSH levels can be measured to rule out hypothyroidism, which can be a cause of tics. Brain imaging studies are not usually warranted.[39] In teenagers and adults presenting with a sudden onset of tics and other behavioral symptoms, a urine drug screen for cocaine and stimulants might be necessary. If a family history of liver disease is present, serum copper and ceruloplasmin levels can rule out Wilson's disease.[9] Most cases are diagnosed by merely observing a history of tics.[22]
Secondary causes of tics (not related to inherited Tourette syndrome) are commonly referred to as tourettism.[31] Dystonias, choreas, other genetic conditions, and secondary causes of tics should be ruled out in the differential diagnosis for Tourette syndrome.[9] Other conditions that may manifest tics or stereotyped movements include developmental disorders, autism spectrum disorders,[40] and stereotypic movement disorder;[41][42] Sydenham's chorea; idiopathic dystonia; and genetic conditions such as Huntington's disease, neuroacanthocytosis, Hallervorden-Spatz syndrome, Duchenne muscular dystrophy, Wilson's disease, and tuberous sclerosis. Other possibilities include chromosomal disorders such as Down syndrome, Klinefelter syndrome, XYY syndrome and fragile X syndrome. Acquired causes of tics include drug-induced tics, head trauma, encephalitis, stroke, and carbon monoxide poisoning.[9][31] The symptoms of Lesch-Nyhan syndrome may also be confused with Tourette syndrome.[24] Most of these conditions are rarer than tic disorders, and a thorough history and examination may be enough to rule them out, without medical or screening tests.[22]}