Australian Doctor - Medical Articles
Tics and Tourette's syndrome
Interview with Dr Stephen Koder by Sue Quayle
Staff specialist in child and adolescent psychiatry Dr Stephen Koder spoke to Sue Quayle about the diagnosis and management of children with tics.
Although tic disorders affect up to 10% of school-aged children and often resolve spontaneously, they can be embarrassing for a child and worrying for parents.
At the mild end of the spectrum, a tic disorder may comprise brief bouts of involuntary movements such as sniffing, eye blinking, head jerking and shoulder shrugging.
Although noticeable to others and sometimes the source of teasing, simple motor tics do not usually prevent an affected child from carrying out tasks of everyday life. In most cases, the tic is transient and resolves within 12 months.
Complex motor tics including spinning around, kicking, reaching towards an object or person, appear more purposeful and unfortunately, are more likely to attract rebukes from authority figures such as teachers or ridicule from peers.
These tics may be transient but may also be part of a more severe tic disorder which includes multiple tics and/or vocal tics such as throat clearing or grunting. The frequency of the movements and noises may wax and wane and sometimes be replaced by other tics.
Tics which lasts more than 12 months are considered chronic. The diagnosis of Tourette's syndrome sits at the upper end of the spectrum and is made when a child with a chronic tic has not been tic-free for more than three consecutive months, and has both motor and vocal tics either concurrently or sequentially, with no other medical or drug-related cause for the tics.
Tourette's syndrome was first described in 1825 and later identified by the French physician, Gilles de la Tourette, in 1895. Tourette's syndrome is believed to have a population prevalence of about one percent but due to the range of severity of Tourette's syndrome, many cases are never diagnosed.
Coprolalia (uttering obscenities) is often the most memorable symptom of Tourette's syndrome among the public. Because it is dramatic and attention-grabbing, it is usually portrayed in popular media depictions of Tourette's sufferers. However, this complex vocal tic is rare and occurs only in the most severely affected individuals.
Tic disorders have a strong genetic influence and appear related to the sensitivity of dopamine receptors in the basal ganglia. Other brain transmitters including noradrenoline and serotonin, and endogenous opioids may also be implicated.
Twin studies show a concordance rate of up 90% for chronic tics and Tourette's syndrome in monozygotic twins. Environmental factors also have a role because in discordant identical twins, the child who manifests the condition is usually the smaller, less well-nourished one of the pair.
Tics are more common in boys than girls and usually first manifest from about seven to eleven years of age. Parents may describe the child's twitch as a habit but this is differentiated relatively easily. Habits usually occur within a context and the behaviour can often be predicted. A tic occurs suddenly and in bouts with the appearance of being beyond the child's control.
Eye blinking is the most common simple motor tic GPs are likely to encounter. After conducting a neurological examination and excluding an eye irritation or visual problems, parents can be reassured that the tic will probably resolve in the ensuing months.
A twitching nose is another common presentation where conditions such as allergic rhinitis should be excluded before a tic is diagnosed.
Family history may reveal that a parent also suffered a tic as a child. It is also advisable to check the family history for other problems such as Wilson's disease, which may present as movement disorders.
It is prudent to ask teenagers about substance abuse as CNS stimulants such as cocaine, can also cause tics.
Multiple tics may occur in association with learning difficulties, developmental delay, obsessive/compulsive disorder and ADHD, particularly if the child is receiving stimulant medication. Dexamphetamine and methylphenidate can cause either an emergence or worsening of tic disorders, and may sometimes unmask an underlying Tourette's syndrome. Tics associated with these medications usually resolve after the drugs are stopped, but occasionally the tics persist and become a problem in their own right.
Children can often exert some voluntary control over a tic and may suppress it during the consultation. They may also be reluctant to discuss the tic as thinking about it may bring it on. A family video where the child is incidentally exhibiting the tic may be useful for diagnosis but the child's permission for the doctor to view the video should be obtained first.
No specific investigations are required unless a neurological or other type of movement disorder is suspected. An EEG will not provide additional information for the diagnosis of a tic disorder and neurological imaging studies are used only for research purposes at present.
Management of a tic disorder should explore possible stresses in the child's life at home and school. Stress can exacerbate tics which in turn, often impacts on the child's self-esteem. Helping the child and parents to devise strategies to deal with stress, and providing reassurance and monitoring are the mainstays of management.
Most children with tics have an otherwise normal course of development and do not usually need formal treatment unless they are bothered by teasing, socially ostracised or their motor function is causing problems with classroom work
Even chronic tics can be successfully managed with education, support, reassurance, strategies to decrease stress and by minimising social attention to the tic as much as possible.
Some patients may experience a reactive depression to the tics but major depression is not common. Distress or depression is most likely to occur if the disorder is unrecognised or untreated, particularly if the child is blamed for having the problem and punished for being disruptive at home and school.
Behavioural strategies to suppress tics are successful in some children and adolescents. This includes progressive muscular relaxation (PMR) training and the use of 'competing response' strategies.
PMR is useful as a general stress-management strategy but importantly, it sensitises patients to areas of muscle tension in the body and helps them identify when tics are occurring. Patients are generally unaware of about half of the tics that are occurring.
Tic monitoring is also useful and may be introduced before or after PMR training, depending on the level of the child's co-operation with therapy. The child is asked to sit in front of a mirror for five to 10 minutes each day and note every tic that occurs. Parents are also asked to unobtrusively count the tics.
This provides a baseline of tic severity and also helps patients identify which tic they wish to deal with first. Each tic is managed one at a time and it is a good idea to start with a simple tic to maximise chances of success.
The child and therapist then devise competing response movements which involves building up muscle strength to 'fight the tic'. For example, if the tic involves opening the mouth, the child practises clenching the teeth; if it involves reaching out and touching, the child practises holding his or her hands behind the back.
These movements are practised in clusters of about five minutes three to four times a day whether or not the tic is occurring. They are also used whenever the child notices the tic happening.
Common motor tics usually respond well to competing response movements but other tics such as eye-rolling or vocal tics are often more difficult to control.
Some of the more severe and pervasive tic disorders may benefit from treatment with a dopamine-2 receptor blocker. However, because of the short and long-term side effects associated with these drugs, they should be commenced and monitored by a specialist. Recent research has shown that the addition of low-dose nicotine patches enhances the effect of dopamine-2 receptor blockers in severe Tourette's syndrome.
Haloperidol has traditionally been used but pimozide is often the preferred agent due to better tolerance. However, the use of pimozide requires ECG monitoring as it has been associated with cardiac conduction problems and deaths in higher dosage ranges.
Risperidone is often well tolerated and causes less movement-related side effects. However, it is associated with weight gain and sedation. It may also cause tardive dyskinesia in sensitive individuals as do the other currently available dopamine-2 receptor blockers.
Clonidine may be used in some children and although it is not as effective as the dopamine-2 receptor blockers, it often reduces tic severity enough for the child to manage in social situations. ECG monitoring is also used with clonidine as deaths have been reported in children taking it in combination with stimulant medications.
It is important for young patients and their families to understand that the symptoms of Tourette's syndrome often improve with maturity. They may flare in early adolescent years but if the child is supported and sustained through that period, tics often settle down by late adolescence or early adulthood. Vocal tics particularly, become less frequent and may only recur when the person is very stressed, tired or ill.
Unfortunately, some people continue to be severely affected and this may have implications for social relationships, self concept and employment opportunities.
The Tourette's Association of Australia offers a range of literature and videos about the management of Tourette's syndrome. For more information telephone: (02)9382 3726 or see their web site at www.tourette.org.au
Reprinted with permission from Australian Doctor