Contents
Introduction
A great overview of tic disorders can be found in the review article J Neurol (2006) 253:1-15.
This article focuses on clinically relevant aspects of tic disorders.
What are "Tics"
Hallmark of tic disorders are involuntary/semivoluntary, sudden, rapid, recurrent, unpredictable, non-rhythmic movements (motor tics) and sounds (vocal tics). Distinguishing tics from other hyperkinetic movement phenomena can be tricky; the following characteristics of tics are useful in making accurate diagnosis:
- irregularity of tics distinguish them from tremors
- waxing and waning pattern as well as worsening with stress and excitement can help distinguished tics from compulsions and stereotypies.
- Motor and vocal tics are often preceded by premonitory urges
- Patients are generally able to briefly suppress onset of tics, but the premonitory tension or discomfort/anxiety rises
- Once an episode of tics occur, there is a brief feeling of relief
- Stress, fatigue, and even excitement can exacerbate tics
Consider in the differential diagnosis: stereotypies of autism spectrum disorders, chorea, athetosis, myoclonus, dystonia, paroxysmal dyskinesias, compulsions of OCD, seizures, and, of course, “pseudoseizures,” restless legg syndrome.
Tics can be simple or complex:
Simple tics involve only one motor group.
Simple Tics | Complex Tics | |
Motor Tics | Eye blinking, sticking tongue out, head jeking |
Coordinated patterns of sequential movements: touching the nose, echopraxia, copropraxia, smelling objects, kissing self, others, arm flapping |
Vocal Tics | Barking, yelling, throat clearing | Coprolalia, echolalia, palilalia |
DSM-IV-TR diagnosis
While tics can be primary (idiopathic or inherited) or secondary (due to drugs, infection, or developmental disorders), the DSM-IV classifies tics by other characteristics:
- Tourette Syndrome involves frequent motor AND vocal tics (must have both, but not necessarily concurrently), starting before age of 18 and lasting for 1 year
- If the above tics had been observed for more than 4 weeks, but less than 1 year, the diagnosis is Transient Tic Disorder
- If frequent vocal OR motor tics start before 18 and last for a year, the diagnosis is Chronic Motor or Vocal Tic Disorder
- All other possibilities (onset >18yo, duration <4w) fit under Tic Disorder NOS
Diagnostic Pearls
- Document family history of tics when evaluating a child
- Order TSH: this is a frequent comoridity
- Sudden onset or worsening of symptoms: obtain Group A beta-hemolytic strep swab, ASO titer, and anti-DNAse B leves (think PANDAS)
- Rule out other secondary causes: head trauma, stroke, autism, CO poisoning, hypoglycemia
- Rule out drugs and intoxication as potential causes: antidepressants, anticholinergics, antihistamines, levodopa, antiepileptics
Treatment Pearls
- Behavioral and supportive treatments
- sleep hygeine, physical exercise, emotional support
- habit reversal is a behavioral therapy centered on rinterruption of stimulus-response sequences, shown effective in RCTs
- Pharmocological treatments
- Dopamine-R antagonists: pimozide (most effective, but requires EKG monitoring for arrhythmias and most EPS-inducing) and haloperidol have the strongest evidence.
- Next in line chlorpromazine, fluphenazine, risperdone (may be best tolerated)
- Alpha-adrenergics can ameliorate both tics and comorbid ADHD with milder side effects: clonidine, guanfacine are safe and effective
- Dopamine-R agonists, at low doses (pergolide), benzodiazepines (clonazepam), and calcium-channel blockers (not diltiazem) may have a role;
- SSRIs are used for comorbid OCD
High-yield facts
Tics
- Coprolalia/copropraxia = obscene words and gestures are complex vocal and motor tics
- Echolalia/echopraxia = mimicking other’s sounds and gestures are complex tics as well
- Jerks that last less than 200ms are most likely myoclonus (not tics)
- Cannabis, alcohol, and nicotine may decrease tics
- Stimulants, stress, fatigue, heat exposure, caffeine, dopamine agonists, and beta-hemolytic strep infection can exacerbate tics
Tourette syndrome
- to diagnose TS, need 2 or more motor tics and at least 1 vocal tic at some time during the illness
- onset typically before age of 7
- symptoms typically peak around 9-11 years of age, and subside in adolescence
- less than 10% fully recover
- Common comorbidities include OCD and ADHD
- M:F ratio is 5:1
Further Reading
Facts for Families from AACAP website. Updated in 2004; 1 page pdf
Prescribing Psychotropic Medications to Children Practice parameters from AACAP. Updated 2009
Tourette Syndrome Association has medical articles, family information, and videos on TS
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