Movement Disorders: Involuntary Tic Disorders

Introduction to Tic Disorders for MCCQE1

Tic disorders, particularly Tourette Syndrome (TS), are high-yield topics for the MCCQE1 under the Neurology and Pediatrics sections. As a Canadian medical student, you must understand the clinical presentation, the spectrum of severity, and the Canadian guidelines regarding management, which prioritize behavioral interventions over pharmacotherapy in mild cases.

Definition: Tics

Tics are sudden, rapid, recurrent, non-rhythmic motor movements or vocalizations. A hallmark feature distinguishing tics from other hyperkinetic movement disorders (like chorea or myoclonus) is that tics are often suppressible for short periods and are frequently preceded by a premonitory urge (a sensation of building tension).

Classification of Tics

Understanding the classification is essential for diagnosing the specific type of tic disorder.

Type	Description	Examples
Simple Motor	Involve a single muscle group; brief (<100 ms).	Eye blinking, shoulder shrugging, facial grimacing, head jerking.
Simple Vocal	Meaningless sounds/noises.	Throat clearing, sniffing, grunting, coughing.
Complex Motor	Coordinated, sequenced movements; appear purposeful.	Touching objects, hopping, echopraxia (mimicking movements), copropraxia (obscene gestures).
Complex Vocal	Linguistically meaningful words or phrases.	Palilalia (repeating own words), echolalia (repeating others), coprolalia (obscene words - rare, <10% of cases).

DSM-5 Diagnostic Criteria

The MCCQE1 tests your ability to distinguish between Provisional Tic Disorder, Chronic Tic Disorder, and Tourette Syndrome based on duration and symptom variety.

1. Tourette Syndrome (TS)

Both multiple motor tics and at least one vocal tic have been present at some time during the illness (not necessarily concurrently).
Tics may wax and wane in frequency but have persisted for >1 year since first tic onset.
Onset is before age 18 years.
Disturbance is not attributable to a substance (e.g., cocaine) or another medical condition (e.g., Huntington’s, post-viral encephalitis).

2. Persistent (Chronic) Motor or Vocal Tic Disorder

Single or multiple motor or vocal tics have been present, but not both motor and vocal.
Persists for >1 year.
Onset before age 18.

3. Provisional Tic Disorder

Single or multiple motor and/or vocal tics.
Present for <1 year.

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Canadian Epidemiology: Tourette Syndrome affects approximately 0.6% to 1% of Canadian children. It is 3-4 times more common in males than females. The peak severity of symptoms typically occurs between ages 10 and 12 years, often improving by late adolescence.

Comorbidities: The “Triad”

For MCCQE1 preparation, recognizing comorbidities is as important as diagnosing the tics themselves. Pure TS is rare; most patients have comorbid neuropsychiatric conditions.

ADHD

Most common comorbidity (~60%). Often precedes the onset of tics.

OCD

Occurs in ~50% of patients. Obsessions often relate to symmetry or exactness.

Anxiety/Mood

Generalized anxiety and depression are frequent, especially in adolescents.

Clinical Evaluation

Follow this step-by-step approach to evaluate a patient presenting with tics, aligned with the CanMEDS framework for thorough assessment.

Step 1: Detailed History

Focus on the onset, trajectory (waxing and waning), and nature of movements.

Key Question: “Do you feel an urge to move before it happens?” (Premonitory urge).
Key Question: “Can you stop them if you really try?” (Suppressibility).
Key Question: “Do they happen during sleep?” (Tics usually diminish or stop during sleep, unlike seizures).

Step 2: Screen for “PANDAS” / “PANS”

While controversial, abrupt onset of severe tics and OCD following a streptococcal infection may suggest PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections).

MCCQE1 Note: This is a diagnosis of exclusion. Do not jump to this diagnosis without a classic history of abrupt, explosive onset.

Step 3: Physical Examination

Perform a complete neurological exam to rule out secondary causes.

Wilson’s Disease: Check for Kayser-Fleischer rings (slit lamp) and hepatosplenomegaly if age > 5 years.
Huntington’s Disease: Look for sustained chorea (unlikely in classic pediatric presentation).
Sydenham’s Chorea: Look for “milkmaid’s grip” and darting tongue.

Step 4: Investigations

Diagnosis is clinical. Neuroimaging (MRI) and EEG are not routinely indicated unless there are atypical features (e.g., seizure-like activity, focal neurological signs, onset in adulthood).

Management and Canadian Guidelines

The management of tic disorders in Canada follows a stepped-care approach. Education and behavioral therapy are the cornerstones.

Treatment Hierarchy

1. Education & Behavioral

First-Line Strategy

Psychoeducation: Reassure the patient and family that tics are involuntary and often improve with age. Address the school environment (CanMEDS Health Advocate).
CBIT (Comprehensive Behavioral Intervention for Tics): This is the gold standard non-pharmacologic treatment in Canada. It involves Habit Reversal Training (HRT)—teaching the patient to recognize the premonitory urge and perform a competing response.
Watchful Waiting: Appropriate for mild tics that do not cause functional impairment or pain.

Canadian Guideline Highlights

Treat the most impairing condition first: If a child has TS and severe ADHD, treating the ADHD (often with stimulants) is prioritized.
Stimulant Myth: Current evidence suggests that stimulants (Methylphenidate) for ADHD do not permanently worsen tics in most patients, though they may cause a transient increase. They are not contraindicated in TS if ADHD is the primary impairment.

Key Points to Remember for MCCQE1

Diagnosis: Tics are suppressible and have a premonitory urge. TS requires Motor + Vocal tics > 1 year.
Comorbidities: Always look for ADHD and OCD.
First-line Management: Psychoeducation and “Watchful Waiting” for mild cases. CBIT for moderate cases.
Pharmacology: Clonidine/Guanfacine are generally preferred over antipsychotics initially due to a better safety profile.
Imaging: Not required for typical presentations.
Prognosis: Symptoms typically peak in early adolescence (10-12 years) and improve in late adolescence.

Sample Question

Clinical Scenario

A 9-year-old boy is brought to the clinic by his parents due to a 14-month history of frequent eye blinking and throat clearing. The parents report that the movements wax and wane but have never completely disappeared. The child describes a “itchy feeling” in his eyes before he blinks. He performs well academically, has friends, and states that the movements do not bother him significantly, although his teacher has mentioned them. Physical examination is unremarkable aside from the observed tics. He has no other medical history.

Question

Which of the following is the most appropriate initial management step?

A. Initiate oral Clonidine
B. Refer for Magnetic Resonance Imaging (MRI) of the brain
C. Initiate oral Haloperidol
D. Psychoeducation and monitoring
E. Refer for Electroencephalogram (EEG)

Click to reveal the answer and explanation

Explanation

The correct answer is:

D. Psychoeducation and monitoring

Detailed Analysis:

Diagnosis: The patient meets the criteria for Tourette Syndrome (multiple motor tics + vocal tic, >1 year duration, onset <18).
Reasoning: The Canadian guidelines and general best practices for Tourette Syndrome emphasize that treatment should be hierarchical and based on functional impairment.
- This patient has tics, but they are not bothersome to him and he is functioning well socially and academically.
- Therefore, the risks of pharmacotherapy outweigh the benefits.
- Psychoeducation for the patient, parents, and teacher (to prevent bullying or misunderstanding) combined with monitoring is the gold standard initial step.
Why other options are incorrect:
- A (Clonidine): While Clonidine is a first-line pharmacological agent, medication is reserved for tics that cause functional impairment (pain, social isolation, academic disruption).
- B (MRI) & E (EEG): Neuroimaging and EEG are not indicated for typical Tourette Syndrome with a normal neurological exam. They are only used if there are atypical features (e.g., seizures, focal deficits).
- C (Haloperidol): This is a typical antipsychotic with a heavy side-effect profile (EPS, tardive dyskinesia). It is rarely a first-line agent and certainly not for mild, non-impairing cases.

References

American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.). Arlington, VA: American Psychiatric Publishing.
Pringsheim, T., et al. (2012). Canadian Guidelines for the Evidence-Based Treatment of Tourette Syndrome. Can J Psychiatry. Link to resource
Medical Council of Canada. (2023). MCCQE Part I Objectives: Neurology.
Doja, A. (2010). Evidence-based management of Tourette’s syndrome. Paediatrics & Child Health.