Tourette's Syndrome and Tics

Tourette's Syndrome and Tics

Tics are sudden, rapid, intermittent but recurrent / repetitive, involuntary (or semivoluntary) nonrhythmic movements (motor tics) or sounds (vocal tics)

- characterized by premonitory urge and suppressibility

- often mimic fragments of normal behaviour through simple or more complex coordinated sequential movements, gestures or utterances

Types of tics:

1. Simple motor tics: involve only single muscle or group of muscles, usually causing brief jerky movement (clonic tics) incl. eye blinking, eyebrow raising, grimacing, head jerking, bruxism, and even gaze shifts

- can also be slower leading to sustained postures (dystonic tics) incl. blepharospasm, ocular deviations, bruxism (teeth grinding), mouth opening, torticollis, and shoulder rotation

- also isometric contraction (tonic tics) with tensing of limb or abdominal muscles

2. Complex motor tics: involve more than one group of muscles, usually forming coordinated sequential series of movements

- incl. head shaking, bending over, touching, hitting, jumping, throwing, making rude gestures incl. grabbing own genitalia (copropraxia) and imitating others' gestures (echopraxia)

- overlap with compulsions when complex movements or sounds preceded by anxiety or fear that if not promptly done, "something bad will happen"

3. Simple phonic tics: sniffing, grunting, throat clearing, clicking, coughing, barking, blowing, humming

4. Complex vocal tics: involve linguistically meaningful utterances and verbalizations such as shouting of obscenities (coprolalia), repetition of someone else's words (echolalia) and repetition of own utterances, esp last syllable or word in phrase (palialia)

NB: actual coprolalia is rare in tic disorders but often people repress full vocalization and may only utter fragments such as "sh.."

Most tics are preceded by premonitory sensations such as localized discomfort or paresthesias which are relieved temporarily by carrying out tic (else develop anxiety)

(eg. burning in eye before blink, crick in neck relieved by jerking head, nasal stuffiness before sniffing or itching before rotation of scapula)

- may also have less localized urge or anxiety which is relieved by repeating particular movement till "feels good"

- some have particular auditory or visual cues that precipitate tics such as particular word or specific shapes

- can suppress the tics for a period, but inevitably build up and this strategy simply leads to more anxiety and discomfort

- may change over time and usually evolve, rather than being static and unchanging

Differentiating tics from other movement disorders:

- may often be confused with myoclonus, stereotypies (see below), chorea, or dystonia

- main feature that separates tics from these is ability to suppress tics (at least transiently)

- most note reduction in tics when concentrating or physically active (incl. video games) while dystonia and other movements often emerge at these times

- tics also usually suggestible and made worse by stress, excitement, fatigue, boredom and heat exposure

- frequency often higher during relaxation after periods of stress (ie. "let go" - for example "release" on coming home after day at school); also more at start of school year

- often occur in bouts of many at a time, separated by seconds, w/variable inter-bout intervals and change over time (so unusual to see one single stereotyped repetitive tic only - in this case consider stereotypies as described below, or focal seizures)

- may persist even during sleep

- also differentiate from motor restlessness and akathisia (usually in legs, unable to sit still, often drug-induced), restless legs syndrome, excessive startle (hyperekplexia) and normal mannerisms

- psychogenic movements often have abrupt onset, not change over time, and reduced with distraction (while tics may increase)

Stereotypies:

- may also look like tics with repetitive involuntary movements but more stereotyped, usually in developmentally delayed children (rarely can be seen in normal children where prognosis is usually better, stop over time)

- not able to suppress and not associated with urge or anxiety

- usually earlier age of onset (ie. infancy) which is unusual age for tics to start

- not change or evolve over time as tics do, but very repetitive (eg rocking, nodding, pacing)

- may occur in reponse to boredom or excitement

- akin to habits and mannerisms

Often not bother patient themselves but socially embarrassing, interfere with job or school (by distracting) and may be uncomfortable

- treat only if interfering with life or patient wishes

- tic severity and frequency often fluctuate markedly over time

Classification of Tic Disorders:

1. Primary causes:

a. Sporadic tics:

- Transient motor and/or vocal tics (< 1 yr) - occurs in up to 20% of children

- Chronic motor or vocal tics (> 1 yr) - 3%

- Adult-onset recurrent tics

- Tourette's syndrome * (most common tic disorder)

- Primary dystonia

b. Inherited tic disorders:

- Tourette's syndrome

- Huntington's disease

- Primary dystonias

- Neuroacanthocytosis

- Hallervorden-Spatz (PANK2-degeneration)

- Tuberous sclerosis

- Wilson's disease

2. Secondary causes: rare, often associated neurological signs

a. Infectious

- Encephalitis, CJD, Neurosyphilis, Sydenham's chorea (with Group A Strep infection)

b. Tardive tics (with drugs)

- Amphetamines, methylphenidate, premoline, levodopa, cocaine, carbamazepine, phenytoin, phenobarbital, lamotrigine, antipyschotics / dopamine-blockers

c. Toxins: carbon monoxide

d. Developmental disorders:

- incl. static encephalopathies, mental retardation syndromes, autistic-spectrum disorders (eg. Asperger's syndrome)

e. Chromosomal disorders:

- Down's syndrome, Klinefelter's syndrome, fragile X syndrome, Beckwith-Wiederman, citrullinemia, and others

f. Misc incl. head trauma, stroke, neurocutaneous disorders, schizophrenia

Tourette's Syndrome

Neurological disorder named after French physician, George Gilles de la Tourette

- described children with multiple tics in 1885 (aka "Gilles de la Tourette syndrome" or GTS)

- felt it was hereditary, though many felt it was psychogenic for decades

- often both parents will have features or forme fruste of Tourette's also (or OCD features)

- 90% monozygotic twin concordance for GTS

Diagnostic Criteria:

1. Age of onset < 21 years

2. Both multiple motor and one or more vocal tics, both present at some time during illness

- not necessarily concurrent, vocal usually later onset than motor

3. Tics present for over one year (never tic-free for > 3 months)

4. Tics occurring multipe times per day

5. Location, frequency, type, severity and complexity of tics must change over time

Epidemiology:

most common cause of tics

- prevalence in schools around 0.7% (some estimates as high as 4.2% for all tic disorders)

- affects boys three times more than girls

- onset before age 11 in 96%, starting mostly between ages 3 and 8 years

- tics almost always evolve and change over time

- usually more severe around age 10, then half resolve by age 18 (but may persist into adulthood, usually at reduced severity)

- if adult-onset tics (not just peristence of childhood-onset tics) search for secondary causes such as infection or drug use / tardive syndrome with neuroleptics

- neurological examination should be normal except for some motor clumsiness

ADHD / OCD Overlap & Behavioural Disturbance:

Many patients with GTS have features of attention-deficit hyperactivity disorder (50% esp in boys) and obsessive-compulsive disorder (50% esp girls) with behavioural problems prominent (incl. poor impulse control, inability to control anger, oppositional behaviour, anxiety / depression)

- these may interfere with functioning more than tics themselves and these traits are more likely to persist into adulthood

- ADHD often begins first at age 3-4 years while OCD presents at age 7 or later

- can also have self-injurious behaviour such as biting, scratching or hitting (often with compulsion-like features, incl. urge)

- rage attacks occur in up to 25% (characterised by feeling bad afterwards) while only 10% have oppositional defiant disorder (ODD - no repentance)

- anxiety is also a major problem in tic disorders and treating anxiety may lessen tics

- may have higher incidence of migraine (one study, 26%)

Pathogenesis:

Most likely an inherited neurodevelopmental disorder of synaptic transmission

- resulting in disinhibition of cortico-striatal-thalamic-cortical circuitry

- no specific structural changes seen in brains of GTS patients but dysfunction in caudate nucleus and inferior prefrontal cortex implicated

- may have loss of normal asymmetry between two sides of basal ganglia (right larger)

- functional studies with fMRI show decreased activity in ventral GP, putamen, thalamus and increased activity in prefrontal and cingulate regions of cortex

- PET study showed increased metabolic activation in lateral premotor and supplementary motor cortices and decreased in caudate and thalamus

- neurophysiological studies with back-averaging showed that the premovement potential (Bereitschaftspotential) is absent before execution of tics suggesting not voluntary (in some)

- TMS has shown shortening of cortical silent period with defective intracortical inhibition

- response to dopaminergic modulation has suggested abnormality in neurochemistry incl. dopaminergic hyperinervation of ventral striatum and associated limbic system and increased density of D2 receptors (with abnormal regulation of dopamine uptake and release)

- no single gene located despite extensive searches but felt to be autosomal dominant with incomplete penetrance

- peak CNS levels of dopamine occur at approx 10 years of age (when tics tend to peak also)

- elevated titres of antistreptococcal antibodies found in some patients raising theory that antineuronal antibodies may play a role (post-infectious syndrome) but definite connection remains unproven

Investigation:

Ascertain age of onset, types of tics, frequency / severity and whether movements can be suppressed transiently

- ask about features of ADHD and OCD, as well as behavioural disturbances

- most importantly assess individual impairment of overall functioning

- medication exposure history (past and present)

- consider imaging if atypical or late-onset

- if acute onset, consdier ASO (Strep) titres for post-infectious tic disorder

- consider thick blood smear for neuroacanthocytosis

Treatment:

1. Education of patient and family members (as well as teachers)

- informed and supportive environment at home and school important (reassurance)

- support groups may be useful +/- counseling to help manage

- good sleep hygiene, regular physical exercise also may be protective

- not useful to encourage suppressing tics as they build up, lead to anxiety, and this is counterproductive

- habit reversal training helps modify behaviours into more acceptable tics

2. Pharmacotherapy:

- if symptoms interfering with social interactions, peer relationships, academic performance

- do NOT treat the family or the school, but only the patient themselves (education of prime importance for these other stakeholders)

- target the most troublesome symptom first (ie. individualized)

- need adequate length trial as natural waxing and waning nature of tics in GTS can confound apparent benefits

Tics:

- goal is not to abolish all tics but relieve discomfort or embarrassment and control tics enough to allow optimal social functioning

- dopamine-receptor blocking drugs best studied (incl. haloperidol, pimozide) eg. Orap (pimozide) 4-8 mg daily

- now atypical neuroleptics increasingly used, with evidence for risperidone (1-2 mg bid)

- dopamine depleters such as tetrabenazine also reduces tics and does not have risk of tardive dyskinesia (eg. Nitoman 75-100 mg per day)

- neuroleptics cause sedation, often weight gain (esp risperidone), school phobia and depression (tetrabenazine esp); exacerbation of tics may occur with withdrawal

- extrapyramidal side-effects incl. tardive dyskinesia can occur with all these agents

- clonidine can also be tried and is useful for impulse control and ADHD as well (start at 0.025 mg or 0.05 mg up to total dose of 0.2-0.3 mg/d TID or more, risk of hypotension and rebound hypertension if abrupt withdrawal, also sedating)

- local injections of botulinum toxin can be helpful in ameliorating premonitory symptoms and tics if localized to one site mainly

Behavioural Symptoms:

- behavioural modifications and adjustments in classroom environment first-line

- close monitoring, small classes and use of teacher's aides

- often prime importance is controlling these

ADHD:

- stimulants such as methylphenidate (Ritalin) or dextroamphetamine

- can lead to nervousness, irritability, anorexia / weight loss, insomnia, headaches, abdominal pain and possible development of tolerance

- concern that they can increase frequency and intensity of tics but usually well tolerated in those with GTS and ADHD (can combine with neuroleptics if required to control both or use with clonidine which is effective for attention deficits and tics)

- idiosyncratic transient worsening of tics may be seen but large trial showed no overall worsening of tics with Ritalin

OCD:

- serotonergic agents such as clomipramine, SSRIs (fluoxetine)

- treating anxiety may help attenuate the tics

Natural History:

- often marked fluctuations in severity and frequency of tics over time

- peaking around age 10 in most

- half resolve by age 18 but others persist into adulthood (but usually less severe)

References:

Leckman JF. Tourette's syndrome. Lancet 2002; 360: 1577-86.

Jankovic J. Tourette's syndrome. N Engl J Med 2001; 345: 1184-92.

Last update: November 2004

Reviewed by: pending review

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