Sarah M. Roddy, MD
DESCRIPTION
- Tics are a movement disorder characterized by brief, repetitive, stereotyped movements or sounds. Tic disorders are classified along a spectrum based on severity.
- Transient tic disorder: Single or multiple motor and/or vocal tics, which have occurred for <1 year.
- Chronic tic disorder: Single or multiple motor or vocal tics, but not both, which have persisted for >1 year.
- Tourette's syndrome (TS): Multiple motor and 1 or more vocal tics, which have persisted for >1 year.
EPIDEMIOLOGY
Incidence
- The exact incidence of TS is unknown, but estimates suggest up to 1% of children.
- Tics begin most commonly by age 6–7 years and always before 18 years.
- Males are more commonly affected than females.
- Transient tics occur in up to 20% of children.
Prevalence
The prevalence is unknown, but it is estimated that 200,000 Americans have the most severe form of TS.
RISK FACTORS
- Risk factors include male sex and a family history of tics and obsessive–compulsive disorder (OCD).
- In patients with TS, stress, fatigue, and excitement may exacerbate tics.
Genetics
TS is a genetic disorder with an unclear mode of inheritance, but evidence suggests polygenic inheritance.
GENERAL PREVENTION
- There is no known prevention for TS.
- Tics may be reduced, though, by decreasing stress.
PATHOPHYSIOLOGY
There is faulty inhibition of the cortical–subcortical pathways resulting from a complicated interplay of mainly dopamine but also gamma-aminobutyric acid (GABA), glutamate, serotonergic, noradrenergic and cholinergic pathways.
ETIOLOGY
- There is no precise etiology known.
- Streptococcal infection or other environmental factors may play a triggering role in some genetically susceptible individuals.
COMMONLY ASSOCIATED CONDITIONS
- 50% of patients with TS have attention deficit hyperactivity disorder (ADHD).
- 20–90% of patients with TS have OCD.
- There is a higher incidence of learning disabilities in children with TS.
- Episodic outbursts and self-injurious behaviors such as hitting or biting oneself are relatively common.
HISTORY
- Tics develop abruptly, with initial tics usually being motor tics. Common motor tics include eye blinking, head jerking, and facial grimacing.
- Vocal tics include throat clearing, sniffing, grunting, and coughing. Coprolalia, which is involuntary swearing, develops in about 10% of patients and is not usually present until 4–7 years after initial symptoms.
- Tics vary in frequency, location, type, and severity. Although initial tics may involve the head, over time the tics often involve the limbs and trunk.
- Tics may spontaneously wax and wane, and there may be periods of days to months when all symptoms disappear. They also change over time, with 1 tic disappearing and another developing.
- Patients can voluntarily suppress tics for varying periods of time; however, the suppression creates an inner tension and eventually the tics must be released.
- Tics may occur during sleep whereas most other movement disorders disappear during sleep.
- History should also include symptoms of ADHD and OCD as well as any family history of tics, ADHD, and OCD.
PHYSICAL EXAM
There are no diagnostic findings on exam. The patient may suppress the tics during the exam, and none may be witnessed. The patient should be observed when leaving the visit since the suppressed tics may be released then.
DIAGNOSTIC TESTS AND INTERPRETATION
Lab
Initial Lab Tests
- There is no laboratory test that is diagnostic for TS.
- The diagnosis is based on clinical criteria.
- If there is a preceding history of sore throat, tests for streptococcal infection including anti-streptolysin titer or streptozyme may be indicated.
Imaging
Initial Approach
Neuroimaging studies do not show any structural abnormalities and are not helpful in making the diagnosis.
Follow-Up & Special Considerations
An EEG may rarely be needed to make sure that a motor tic is not seizure activity.
Pathological Findings
- There are no diagnostic pathological findings.
- There are limited neuropathological studies in postmortem brains, but a marked reduction in the number and density of GABAergic parvalbumin-positive cells in the basal ganglia has been found.
DIFFERENTIAL DIAGNOSIS
MEDICATION
First Line
- Clonidine reduces tics in some children and can also be helpful for treatment of ADHD (1)[B].
- A dose of 0.05 mg per day is started and increased by 0.05 mg q 5–7 days to a maximum of 0.2–0.3 mg/day. Clonidine has a short half-life, so t.i.d. or q.i.d. dosing is often required. The patch form has the advantage of providing a constant level of medication.
- Contraindications include documented hypersensitivity. Use with caution if renal or hepatic function is impaired.
- Patients need to be monitored for sedation and hypotension and, in those treated with the transdermal form, skin reaction. It is advisable not to abruptly stop the medication because of the risk of hypertension.
- Guanfacine treats tics and comorbid ADHD and is less sedating than clonidine (1)[B].
- The initial dose is 0.5 mg at h.s. with the dose increased by 0.5 mg q 5–7 days to a maximum of 4 mg/day given b.i.d.
- Use with caution in patients with cerebrovascular disease or impaired hepatic and renal function.
- Adverse effects include sedation, dizziness, and hypotension.
Second Line
- Pimozide is a typical neuroleptic and may be more effective for tics than the first-line drugs but may cause more side effects than the first-line drugs. It is less sedating than haloperidol (2)[A].
- The initial dose is 0.5–1 mg q.h.s. with an increase by 0.5–1 mg q 5–7 days as needed. The usual dose is 2–4 mg divided b.i.d. with a maximum daily dose of 10 mg.
- Contraindications include prolonged QT interval and history of cardiac arrhythmias.
- Because pimozide can prolong the QT interval, patients need to have an EKG prior to starting treatment and regular EKG monitoring.
- Fluphenazine is a traditional neuroleptic that is effective in controlling tics (3)[B].
- A dose of 0.5–1 mg q.h.s. is started with weekly increases as needed to a maximum dose of 5 mg divided b.i.d.
- Severe cardiac disease and liver disease are contraindications.
- Side effects include weight gain, drowsiness, extrapyramidal reactions, and restlessness.
- Haloperidol was the first neuroleptic shown to be effective for tic suppression and may be the most effective for severe cases (3)[A].
- A dose of 0.5 mg q.h.s. is started, with an increase of 0.25–0.5 mg weekly until satisfactory tic control is achieved. Doses >4 mg per day are rarely required.
- Contraindications in children are unusual but include cardiac and liver disease and history of acute dystonia.
- Patients need to be monitored for lethargy, weight gain, personality changes, cognitive impairment, and school phobia. Tardive dyskinesia is a potential side effect from use of haloperidol, but this rarely occurs in children with tics.
- Risperidone is an atypical neuroleptic that may improve tics and can be helpful for impulsive and oppositional behavior (1)[A].
- The initial dose is 0.25–0.5 mg q.h.s. The dose can be increased as needed every week to a maximum of 4 mg divided b.i.d.
- Contraindications in children are unusual but include prolonged QT interval.
- Side effects include weight gain, hyperglycemia, and dystonic reactions.
ADDITIONAL TREATMENT
General Measures
- Explaining the nature of TS to the child and family is the most important initial intervention.
- Parents need to know that tics are involuntary and that children should not be punished for symptoms they cannot control.
- They also need to understand that tics are not a sign of psychological disease but that stress can exacerbate the symptoms.
- Any events or conditions that exacerbate tics should be identified and eliminated if possible.
- Parents should be educated to ignore tics as much as possible, because focusing attention on them often increases the frequency of tics.
- Management should also focus on educational issues that may result from the tics or associated ADHD or OCD. A comprehensive neuropsychological assessment can help determine what interventions will be helpful to make the child successful in school.
- Pharmacotherapy is indicated for children whose symptoms impair their psychosocial or educational functioning.
Additional Therapies
- Behavioral therapy, including relaxation therapy, habit reversal training, and comprehensive behavioral intervention for tics, is helpful in some patients. Behavior therapy is not widely available, and not all patients have long-term benefits.
- Atomoxetine or stimulants such as methylphenidate or dextroamphetamine can improve the attention span and help with impulsive behavior. Stimulants can be used in children with tics with very little risk of worsening tics.
- Selective serotonin reuptake inhibitors, such as fluoxetine, sertraline, fluvoxamine, or paroxetine, may help decrease OCD symptoms. These medications usually must be given for 4–6 weeks before improvement is seen.
- Local intramuscular injection of botulinum toxin (Botox) can reduce a single severe motor tic but the benefits last only 3–6 months.
COMPLEMENTARY AND ALTERNATIVE THERAPIES
- Acupuncture has been reported to be effective in some small trials.
- There is no convincing evidence that vitamin or mineral preparations or special diets are helpful.
SURGERY/OTHER PROCEDURES
Deep brain stimulation has been helpful in some patients refractory to medical management. The criteria for identifying patients who will have the greatest benefit from this procedure have not been determined.
IN-PATIENT CONSIDERATIONS
Admission Criteria
It is very unusual for patients with TS to require admission for their symptoms.
FOLLOW-UP RECOMMENDATIONS
Patient Monitoring
Patients with mild symptoms who do not need medications can be followed on an as-needed basis. Patients with more severe symptoms will need follow-up every few weeks to months to monitor medication response, school progress, and psychosocial issues.
DIET
There is no special diet that helps the tics.
PATIENT EDUCATION
- The Tourette Syndrome Association provides many services for patients, families, physicians, and caregivers. Local chapters throughout the country provide additional services, including support groups. Tourette Syndrome Association, 42-40 Bell Boulevard, Bayside, NY 11361-2820. Phone: 718-224-2999, fax: 718-279-9596, website: http://tsa-usa.org
- “Tourette Syndrome Fact Sheet” NINDS.
PROGNOSIS
- Approximately one third of patients have complete remission of tics by late adolescence. An additional third of patients report that their tics significantly lessen in frequency and severity by late adolescence. The remaining third of patients continue to be symptomatic into adulthood, although in some there may be continuing gradual improvement throughout life.
- ADHD symptoms tend to improve during the adolescent years, although some patients continue to have symptoms that may affect their occupation.
- OCD symptoms, which tend to begin later than tics, may persist and have a negative impact on the patient's life.
COMPLICATIONS
Tics can lead to muscle soreness and strain and rarely dislocation of a bone.
