Tics and Tourette Syndrome

Tics and related diseases represent a set of neurobehavioral disorders of childhood that are characterized by sudden, repeated, nonrhythmic, stereotyped muscle movements sometimes accompanied by sounds or vocalizations. Tourette syndrome is a severe form with symptoms lasting more than 1 year and involving both motor and vocal tics. Although there is no definitive cause of Tourette syndrome, the condition has genetic and environmental factors that contribute to disease development. Tourette syndrome is clinically diagnosed. Treatment involves behavioral therapy, antipsychotics, and the treatment of comorbid conditions. The majority of children outgrow their symptoms in adulthood, although a minority of adults will continue to demonstrate severe tics.

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Overview

Definition

Tics are repeated, nonrhythmic movements or vocalizations. 

Tourette syndrome is a disorder characterized by at least 1 motor and 1 vocal tic (may not occur at the same time) not caused by medication or other physiological processes, with an age of onset before 18, and lasting for more than 1 year.

Classification

  • Tourette syndrome: motor and vocal tics for 1+ year 
  • Provisional tic disorder: lasting < 1 year, diagnosed in retrospect
  • Chronic motor tics: presence of motor tics (no vocal tics) for 1+ year 
  • Chronic vocal tics: presence of vocal tics (no motor tics) for 1+ year

Epidemiology

  • Tics affect 20% of children worldwide; the severe form (Tourette syndrome) affects 3–8 per 1,000 children.
  • Boy:girl prevalence: 3:1
  • Mainly affects children aged 4–9 years
  • Often improves as patient grows older, and disappears in adulthood 
  • Prenatal maternal smoking thought to be a risk factor
  • Comorbid conditions:
    • OCD OCD Obsessive-compulsive disorder (OCD) is a condition characterized by obsessions (recurring and intrusive thoughts, urges, or images) and/or compulsions (repetitive actions the person is compelled to perform) that are time-consuming and associated with functional impairment. Obsessive-compulsive Disorder (OCD)
    • Depression
    • Anxiety
    • ADHD
    • Self-injurious behavior

Pathophysiology

Causative pathway remains largely unknown, although several theories exist.

  • Genetic influence theory: 
    • Genetic mutation Mutation Genetic mutations are errors in DNA that can cause protein misfolding and dysfunction. There are various types of mutations, including chromosomal, point, frameshift, and expansion mutations. Types of Mutations in developmental period
    • HDC gene on chromosome 15q21-q22, inherited in autosomal dominant Autosomal dominant Autosomal inheritance, both dominant and recessive, refers to the transmission of genes from the 22 autosomal chromosomes. Autosomal dominant diseases are expressed when only 1 copy of the dominant allele is inherited. Autosomal Recessive and Autosomal Dominant Inheritance pattern with incomplete penetrance  
    • SLITRK1 gene on chromosome 13q31.1 expressed in thalamic, subthalamic, and globus pallidus nuclei, striatum, cortex, hippocampus, and cerebellum Cerebellum The cerebellum, Latin for "little brain," is located in the posterior cranial fossa, dorsal to the pons and midbrain, and its principal role is in the coordination of movements. The cerebellum consists of 3 lobes on either side of its 2 hemispheres and is connected in the middle by the vermis. Cerebellum, which are thought to be involved in Tourette syndrome
    • Offspring of parents with tics have a 45% chance of presenting any variant of tics and a 15% chance of developing Tourette syndrome.
  • Autoimmune theory:
    • Preceding infection with group A β-hemolytic streptococci → antibodies Antibodies Immunoglobulins (Igs), also known as antibodies, are glycoprotein molecules produced by plasma cells that act in immune responses by recognizing and binding particular antigens. The various Ig classes are IgG (the most abundant), IgM, IgE, IgD, and IgA, which differ in their biologic features, structure, target specificity, and distribution. Immunoglobulins to basal ganglia Basal Ganglia Basal ganglia are a group of subcortical nuclear agglomerations involved in movement, and are located deep to the cerebral hemispheres. Basal ganglia include the striatum (caudate nucleus and putamen), globus pallidus, substantia nigra, and subthalamic nucleus. Basal Ganglia → pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS)
    • Other associated infections: herpes simplex virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: Overview infection, HIV, mycoplasma Mycoplasma Mycoplasma is a species of pleomorphic bacteria that lack a cell wall, which makes them difficult to target with conventional antibiotics and causes them to not gram stain well. Mycoplasma bacteria commonly target the respiratory and urogenital epithelium. Mycoplasma pneumoniae (M. pneumoniae), the causative agent of atypical or "walking" pneumonia. Mycoplasma pneumonia Pneumonia Pneumonia or pulmonary inflammation is an acute or chronic inflammation of lung tissue. Causes include infection with bacteria, viruses, or fungi. In more rare cases, pneumonia can also be caused through toxic triggers through inhalation of toxic substances, immunological processes, or in the course of radiotherapy. Pneumonia, and varicella zoster virus Virus Viruses are infectious, obligate intracellular parasites composed of a nucleic acid core surrounded by a protein capsid. Viruses can be either naked (non-enveloped) or enveloped. The classification of viruses is complex and based on many factors, including type and structure of the nucleoid and capsid, the presence of an envelope, the replication cycle, and the host range. Virology: Overview (VZV)
  • Neurobiological theory: 
    • Disorder of fibers of cortico-striatal-thalamic-cortical (CSTC) pathway
    • Dopamine linked to improvement

Clinical Presentation

Tics

Simple tics:

  • Brief movement of single muscle or muscle groups or vocalization
  • Movement and vocalizations have no social meaning.
  • Examples of simple motor tics:
    • Eye blinking
    • Eye rolling
    • Limb and head jerking
    • Grimacing
    • Shoulder shrugging
  • Examples of simple sensory tics:
    • Throat clearing
    • Whistling
    • Coughs
    • Grunting
    • Animal sounds

Complex tics:

  • Cluster of simple actions, coordinated movements, or vocalizations that involve repetition of words 
  • Often, movements or words have social meaning.
  • Examples of complex motor tics:
    • Jumping
    • Touching objects and other people
    • Copropraxia: making obscene gestures in public or touching genitals
    • Echopraxia: imitating gestures of others
  • Examples of complex sensory tics:
    • Coprolalia: use of obscene words in public
    • Echolalia: repetition of words said by others
    • Palilalia: repetition of one’s own words

Other tic characteristics:

  • Fluctuating course: 
    • Waxing and waning pattern:  
      • More prominent during stress or fatigue
      • Less prominent when patient is engaged in activity
    • Always absent during sleep Sleep Sleep is a reversible phase of diminished responsiveness, motor activity, and metabolism. This process is a complex and dynamic phenomenon, occurring in 4-5 cycles a night, and generally divided into non-rapid eye movement (NREM) sleep and REM sleep stages. Physiology of Sleep
  • Most common 1st symptom is facial tic (e.g., eye blink, nose Nose The nose is the human body's primary organ of smell and functions as part of the upper respiratory system. The nose may be best known for inhaling oxygen and exhaling carbon dioxide, but it also contributes to other important functions, such as tasting. The anatomy of the nose can be divided into the external nose and the nasal cavity. Anatomy of the Nose twitch, or grimace)
  • Voluntary suppressibility: often associated with build-up of inner tension that resolves when tic is permitted to occur
  • Premonitory sensations: 
    • Sensory phenomena that occur before motor or phonic tic 
    • Take the form of urge, impulse, tension, pressure, itch, or tingle
    • More common in adults

Tourette syndrome

  • Symptoms appear before age 18:
    • Typically appear in school-aged children 
    • Generally worst around age 10
    • Adults usually have mild symptoms that may go unnoticed.
  • Associated with ADHD and OCD OCD Obsessive-compulsive disorder (OCD) is a condition characterized by obsessions (recurring and intrusive thoughts, urges, or images) and/or compulsions (repetitive actions the person is compelled to perform) that are time-consuming and associated with functional impairment. Obsessive-compulsive Disorder (OCD) 
  • Motor tics normally appear 1st: 
    • Upper body tics more common than lower body tics
    • Examples: blinking, grimacing

Diagnosis

  • Diagnosis is clinical, involving identification of specific tic phenomenology. 
  • History and physical examination: 
    • Observe for tics during interview and physical examination.
    • Ask about past medical history of ADHD and OCD OCD Obsessive-compulsive disorder (OCD) is a condition characterized by obsessions (recurring and intrusive thoughts, urges, or images) and/or compulsions (repetitive actions the person is compelled to perform) that are time-consuming and associated with functional impairment. Obsessive-compulsive Disorder (OCD).
    • Ask about family history of tic disorders.
  • Diagnosed when patient has both motor and vocal tics for 1+ year, beginning before age 18
  • Imaging and blood testing may rule out other potential etiologies: 
    • Functional MRI: 
      • Used to demonstrate brain function during occurrence of tics
      • Shows reduced caudate volumes
    • CT: 
      • Employed in investigating associated structural abnormalities 
      • May show reduced caudate volumes
    • EEG: performed during sleep Sleep Sleep is a reversible phase of diminished responsiveness, motor activity, and metabolism. This process is a complex and dynamic phenomenon, occurring in 4-5 cycles a night, and generally divided into non-rapid eye movement (NREM) sleep and REM sleep stages. Physiology of Sleep to ascertain nature of brain activity during tics and distinguish from other causes of involuntary movement
    • PET: shows increased brain activity during tics in thalamus Thalamus The thalamus is a large, ovoid structure in the dorsal part of the diencephalon that is located between the cerebral cortex and midbrain. It consists of several interconnected nuclei of grey matter separated by the laminae of white matter. The thalamus is the main conductor of information that passes between the cerebral cortex and the periphery, spinal cord, or brain stem. Thalamus and striatum
    • Blood testing: rules out chronic disease
    • Urine testing: drug screening (e.g., stimulant use) if there is suspicion for intoxication

Management

Treatment is only needed when the disease interferes with a patient’s image, social activity, or education. Most patients do well with education and CBT, without the need for medication or deep brain stimulation.

  • CBT:
    • Habit reversal therapy:
      • Most effective nonpharmacological treatment
      • Include detailed description of tic to find competing response 
      • Reduces chances of tic occurrence
    • Education about tics: Understanding tics as a neurobehavioral disease helps patients to cope with the disorder.
    • Social support and reward system: Good support reduces associated psychiatric conditions.
    • Functional intervention: identifies environmental events that worsen tics 
    • Relaxation training: reduces stress that could trigger tics
  • Pharmacological therapy/antipsychotics:
    • Alpha-adrenergic agonist (e.g., clonidine, guanfacine) 
    • 1st-generation antipsychotics (e.g., haloperidol)
    • 2nd-generation antipsychotics (e.g., risperidone, olanzapine) 
    • Currently: 2nd-generation antipsychotics are preferred pharmacological treatment due to fewer side effects.
  • Deep brain stimulation:
    • Implantation of electrodes and passage of stimulatory current to selected areas of brain in which increased activity is likely to cause tics
    • Includes thalamus Thalamus The thalamus is a large, ovoid structure in the dorsal part of the diencephalon that is located between the cerebral cortex and midbrain. It consists of several interconnected nuclei of grey matter separated by the laminae of white matter. The thalamus is the main conductor of information that passes between the cerebral cortex and the periphery, spinal cord, or brain stem. Thalamus and globus pallidus
  • Treatment of comorbid conditions:
    • ADHD: low-dose stimulants Stimulants Stimulants are used by the general public to increase alertness and energy, decrease fatigue, and promote mental focus. Stimulants have medical uses for individuals with ADHD and sleep disorders, and are also used in combination with analgesics in pain management. Stimulants 
    • OCD OCD Obsessive-compulsive disorder (OCD) is a condition characterized by obsessions (recurring and intrusive thoughts, urges, or images) and/or compulsions (repetitive actions the person is compelled to perform) that are time-consuming and associated with functional impairment. Obsessive-compulsive Disorder (OCD): antidepressants (e.g., selective serotonin reuptake inhibitors Serotonin Reuptake Inhibitors Antidepressants encompass several drug classes and are used to treat individuals with depression, anxiety, and psychiatric conditions, as well as those with chronic pain and symptoms of menopause. Antidepressants include selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), and many other drugs in a class of their own. Serotonin Reuptake Inhibitors and Similar Antidepressant Medications (SSRIs) such as fluoxetine and clomipramine)
    • Anxiety: CBT and anxiolytics

Differential Diagnosis

  • ADHD: characterized by limited attention and hyperactivity for 6+ months in 2 different social environments. Presentation is classified as predominantly inattentive, predominantly hyperactive, or combined. Patients are diagnosed clinically based upon symptoms lasting more than 6 months, with onset before the age of 12. The disease usually continues into adulthood. Treatment is stimulant medication with other options including non-stimulant medications (e.g., atomoxetine) and behavioral therapy. The disease can cause functional decline.
  • OCD OCD Obsessive-compulsive disorder (OCD) is a condition characterized by obsessions (recurring and intrusive thoughts, urges, or images) and/or compulsions (repetitive actions the person is compelled to perform) that are time-consuming and associated with functional impairment. Obsessive-compulsive Disorder (OCD): characterized by recurring intrusive thoughts, feelings, or sensations (known as obsessions) that are time consuming and cause severe distress; relieved partially by performance of repetitive actions (known as compulsions). Patients diagnosed clinically by presence of obsessions or compulsions that are time consuming and affecting daily life. Treatment includes CBT and medications (e.g., SSRIs).  
  • Oppositional defiant disorder Oppositional Defiant Disorder Oppositional defiant disorder is a pediatric psychiatric disorder characterized by a continuous pattern of angry/irritable mood, argumentative/defiant behavior, or vindictiveness directed at adults or other authority figures. Symptoms must be present for at least 6 months to make a diagnosis of ODD. Oppositional Defiant Disorder (ODD): continuous pattern of angry/irritable mood, argumentative/defiant behavior, or vindictiveness that is present for at least 6 months. This diagnosis is frequently found in those with ADHD. Symptoms of ODD are mostly directed toward authoritative figures, such as parents or teachers.

References

  1. Muller, N. (2007). Tourette’s syndrome: clinical features, pathophysiology, and therapeutic approaches. Dialogues Clin Neurosci. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3181853/
  2. Novotny, M., Valls, M., Klimova, B. (2020). Tourette Syndrome: A mini-review. Front Neurol. https://www.frontiersin.org/articles/10.3389/fneur.2018.00139/full
  3. Pringsheim, T., OKun, M.S., Muller-Vahl, K., et al. (2019). Practice guideline recommendations summary: Treatment of tics in people with Tourette syndrome and chronic tic disorders. https://pubmed.ncbi.nlm.nih.gov/31061208/
  4. CDC. (2021). Diagnosing Tic Disorders. Centers for Disease Control and Prevention. https://www.cdc.gov/ncbddd/tourette/diagnosis.html#provisional

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