Tourette Syndrome

The tics may be either simple or complex. Simple tics may be:

• Blinking
• Shoulder shrugging
• Head nodding or jerking

Complex ones include:

• Scratching 
• Body gyrations
• Kicking
• Jumping
• Seductive and obscene gestures 

The tics are suppressible, but they are associated with an irresistible urge and sensations that are relieved when the tic occurs. Involuntary vocalizations, may range from sounds to words. The words may be obscene (coprolalia) which occurs in 40% of patients with word tics. Some may repeat a single word many times. Many also experience copropraxia (obscene gestures), echopraxia (mimicking of gestures) with unusual fixations and fanaticises. The neurologic exam is usually normal except for the tic [9].

Once the history and exam is taken there is no further workup required to make the diagnosis.

Diagnostic criteria for Tourette syndrome (DSM-IV) are as follows:

• Both multiple motor and 1 or more vocal tics have been present at some time during the illness, though not necessarily concurrently. A tic is a sudden, rapid, recurrent, nonrhythmic, stereotyped motor movement or vocalization.
• The tics occur many times a day (usually in bouts) nearly every day or intermittently throughout a period of more than 1 year, and during this period there was never a tic-free period of more than 3 consecutive months.
• The onset is before age 18 years.
• The disturbance is not due to the direct physiologic effects of a substance (eg. stimulants) or a general medical condition (eg. Huntington disease or postviral encephalitis) [9] [10].

• Dopamine agonists/antagonists reduce the frequency and intensity of the tics in up to 80% of the patients. 
• Habit reversal training includes tic awareness training to try and help the patient prevent the tic before it occurs. The other is compete response training to train the patient to perform a movement that will not allow the tic [11].
• Botulism toxin may be used to paralyse small muscle groups to try and reduce the tic. 
• Others drugs such as topiramate may be useful.

The condition can persist throughout life, in children it can go into remission and 50% will have reduced tics by the age of 18. Some tics are not distressing or life limiting, but other can cause a lot of distress and anxiety. The vocal sounds and words can be profane or loud causing the sufferer to be very conscious in public. Some tics are violent and cause injury to the patient.

The discovery of genes that may be responsible for the syndrome was a big step in trying to elucidate the cause of the Tourette syndrome. The mutation in the SLITRK1 gene on chromosome 13q is expressed in the regions in the brain that are implicated in the disease; these include the hippocampus, cortex, thalamic, subthalamic and globus pallidus nuclei). The gene appears also to be important in dendritic growth.

Other genes have been discovered in families with Tourettes; one of note is the HDC gene located in chromosome 15. There also appears to be non-genetic factors, because there have been differences in monozygotic twins. Proposed postulates include a difference in the immune response to streptococcus infection. There is on-going research to the possible connection with streptococcus infections [2] [3].

The overall international data shows are prevalence of about 1%, but these figures are thought to be unreliable due to different propensities for people to seek medical care in different communities and cultures. The typical age of onset is five to ten years of age.

There is a high incidence of attention deficit hyperactivity disorder (ADHD) (60 percent), and obsessive-compulsive disorder (OCD), in this population [4] [5] [6].

The neurophysiology of this syndrome is not yet known. It is thought to be caused by pathologies in the inferior frontal cortex and the basal ganglia. There appears to be loss of normal asymmetry in these regions on imaging. Biochemical studies from autopsies have shown decreased levels of dopamine but its role in the pathophysiology is not known. There have been signs from of increased dopamine receptors and production. It is thought that problems in the synthesis and uptake of dopamine could be the cause [7] [8].

Genetic counselling is the only know prevention, due to its strong genetic component. Parents with suffering from tics have to know the risks of their offspring having the same condition as them and the associated comorbidities, such as obsessive-compulsive disorder.

Tourette syndrome (TS) is a neurological disorder characterized by tics. Tics are repeated, individually recognizable, intermittent movements or movement fragments that are almost always briefly suppressible and are usually associated with awareness of an urge to perform the movement. The tic can be brief movements of utterances such as sounds or words. Of note these movement disappear with sleep. The tic are suppressible, but the longer they are suppressed the stronger the urge [1].

• Definition: Tourette syndrome is a disorder that causes unusual movements or sounds, called “tics.” Examples include blinking and shrugging. People with the disorder have little or no control over their tics. The symptoms may be mild but some can be sever and distressful. 
• Cause: The cause is thought to be genetic. The abnormal genes are passed down from the parents. It is though that these gene changes cause chemical changes within the bairn.
• Symptoms: Motor tics are tics that involve unusual movements. They can be mild (called “simple motor tics”) or more extreme (called “complex motor tics”). Examples of motor tics include: Blinking, briefly grimacing, and shrugging the shoulders. Vocal tics include throat-clearing, or other noises, or swearing and repeating words or phrases (including echoing what other people say).
• Diagnosis: The diagnosis is made by history and examination. The doctor will make the diagnosis from this and there is rarely any need to do more tests.
• Treatment: These include medicines that can reduce the tics, and habit reversal training which help the patient recognise when the tic is about to happen, so they can prevent it. Other medicines such as botulinum toxin, have been used to paralyse muscles that cause the movements.

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6. Hebebrand J, Klug B, Fimmers R, et al. Rates for tic disorders and obsessive compulsive symptomatology in families of children and adolescents with Gilles de la Tourette syndrome. J Psychiatr Res. Sep-Oct 1997;31(5):519-30
7. Miller AM, Bansal R, Hao X, Sanchez-Pena JP, Sobel LJ, Liu J. Enlargement of thalamic nuclei in Tourette syndrome. Arch Gen Psychiatry. Sep 2010;67(9):955-64
8. Abelson JF, Kwan KY, O'Roak BJ, et al. Sequence variants in SLITRK1 are associated with Tourette's syndrome. Science 2005; 310:317.
9. American Psychiatric Association. American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders, 4th ed, Text Revision. Washington, DC: American Psychiatric Association; 2000.
10. Leckman JF, Zhang H, Vitale A, et al. Course of tic severity in Tourette syndrome: the first two decades. Pediatrics 1998; 102:14.
11. Bockner S. Gilles de la Tourette's disease. J Ment Sci. Oct 1959;105:1078-81