Difference between revisions of "Tic Disorders"

Revision as of 19:39, 21 February 2013

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”

Tics can be simple or complex:

Simple tics involve only one motor group.

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

.

This article is almost complete. You can help Learn Psychiatry by editing it.