Tic disorder (TD) is a neuropsychiatric disorder that begins in childhood and has tics as its main clinical manifestation.
I. Clinical characteristics
1. General characteristics: The age of onset is from 2 to 21 years old, with 5 to 10 years old being the most common. The disease is usually most severe at the age of 10-12; males are significantly more than females, and the ratio of males to females is 3-5:1.
2. Twitching: an involuntary, purposeless, rapid and stereotyped muscle contraction. The manifestations of twitching are complex and varied. The motor twitch is an involuntary, sudden, rapid contraction of the muscles of the head and face, neck and shoulders, trunk and limbs; the vocal twitch is actually a contraction of the muscles of the mouth, nose, throat and whistle, which vocalize through the airflow of the nose, mouth and throat. Motor tics or vocal tics can be further divided into two categories: simple and complex, and sometimes the two are not easily distinguished. Unlike other movement disorders, twitching occurs in the presence of normal motor function and is non-persistent. At the beginning of the disease, twitching symptoms usually start in the face and progress to the head, neck, and shoulder muscles, and then spread to the trunk and upper and lower extremities. The twitching form may change from one form to another, with new forms of twitching constantly emerging. The frequency and intensity of twitching fluctuate significantly during the course of the disease, and new twitching symptoms may replace or superimpose on top of the old twitching symptoms. In children with a long course of the disease, the clinical picture is further complicated by the appearance of twitching or vocalization followed by a rapid attempt to disguise it. Twitching symptoms often come and go, and may resolve temporarily or spontaneously over time, or may be exacerbated or reduced by certain triggers. Factors that commonly aggravate tics include stress, anxiety, anger, shock, excitement, fatigue, infection, and being reminded of the tics. Forty to 55% of children with motor or vocal twitches are preceded by local discomfort, called sensory twitching, which is considered a precursor symptom, especially in older children, including pressure, itching, pain, heat, cold or other unusual sensations. Motor or vocal twitches are likely to be associated with relief of local discomfort.
Co-morbidity: About half of the children have one or more psychological behavior disorders, including attention deficit hyperactivity disorder (ADHD), learning difficulties, obsessive-compulsive disorder, sleep disorders, mood disorders, self-injurious behavior, conduct disorder, and rage attacks. There are gender differences in the occurrence of TD co-morbidities, with ADHD, learning difficulties, conduct disorders, and rage attacks usually occurring more frequently in males, while obsessive-compulsive disorder and self-injurious behavior occur more frequently in females than in males. Co-morbidity further increases the complexity and severity of the disease, affecting the healthy development of the child’s learning, social adjustment, personality and psychological quality, and adding many difficulties to the treatment and management.
Diagnosis
1. Diagnostic methods: There is a lack of specific diagnostic indicators. At present, the diagnosis is mainly made by clinical descriptive diagnosis, based on the child’s tic symptoms and related accompanying mental behavioral manifestations. Therefore, a detailed history is the prerequisite for a correct diagnosis, and physical examination including psychiatric examination and necessary auxiliary examinations are also necessary to exclude other diseases. EEG, neuroimaging and laboratory tests are generally not characteristically abnormal. A few children may have nonspecific changes, such as background slowing or asymmetry in a few children on EEG; non-specific structural changes such as small volume of the caudate nucleus, slightly thin frontal and occipital cortices, mild enlargement of the ventricles, and deepening of the lateral fissure in a few children on cranial cT or MRI. Wilson’s disease) and other organic extrapyramidal diseases.
2, clinical typing: according to the clinical characteristics and duration of the disease, the disease can be divided into three types: transient TD, chronic TD and Tourette syndrome (TS). Transient TD is the most common type with the mildest disease, manifesting as one or more motor tics and/or vocal tics, and the duration of the disease is within 1 year. Chronic TD is defined as a condition that presents with only motor tics or vocal tics (not both) and lasts for more than 1 year. Multiple tic disorder is the more severe type of the disease, showing both motor and vocal tics, but not necessarily both at the same time, and the duration of the disease is more than 1 year. In the past, the term “Tourette’s syndrome” was not appropriate, because the incidence of obscenities was less than one-third, and obscenities were not a necessary condition for the diagnosis of Ts, and it had an obvious pejorative meaning. Transient TD can be converted to chronic TD, and chronic TD can be converted to Ts. Some patients cannot be classified in any of these categories and belong to other types of TD that have not yet been defined, such as TD with adult onset (late-onset TD). Refractory TD is a new concept that has gradually developed in pediatric neurology and psychiatry in recent years, which refers to children with TD who have been treated with conventional anti-TD drugs such as haloperidol and thiopride for more than 1 year in adequate amounts and have not recovered from the disease. A variety of organic diseases can also cause TD, i.e. secondary TD, which should be excluded clinically. There are many causes of secondary TD, including genetic factors (such as Down syndrome, fragile X syndrome, tuberous sclerosis, neuroborreliosis, etc.), infectious factors (such as streptococcal infection, encephalitis, neurosyphilis, Creutzfeldt-Jakob disease, etc.), toxic factors (such as carbon monoxide, mercury, bee poisoning, etc.), and drug factors (such as methylphenidate, pemoline, amphetamine, cocaine, carbamazepine, phenobarbital, phenytoin, lamotrigine, etc.). phenytoin, lamotrigine, etc.) and other factors (such as stroke, head trauma, developmental disorders, neurodegenerative diseases, etc.).
3. Assessment of disease: According to the severity of the disease, it can be divided into mild, moderate and severe. Mild (mild) means that the twitching symptoms are mild and do not affect the child’s life, learning or social activities; moderate means that the twitching symptoms are severe but have less impact on the child’s life, learning or social activities; severe (serious) means that the twitching symptoms are severe and significantly affect the child’s life, learning or social activities. Objective and quantitative assessments can also be made based on tic severity scales, such as the Yale Comprehensive Tic Severity Inventory. In addition, the more co-morbidities associated with TD, the more serious the condition.
4. Diagnostic criteria: It can be based on the International Classification of Diseases, 10th edition (ICD-10), the Diagnostic and Statistical Manual of Mental Disorders, 4th revision (DSM-IV-TR). and the Chinese Standard for Mental Disorders and Diagnosis, 3rd edition (CCMD, III). At present, most scholars at home and abroad tend to adopt the diagnostic criteria in DSM I 1V-TR, which are briefly described as follows.
(1) Transient TD.
① one or more motor twitches and/or vocal twitches.
(ii) Multiple episodes of twitching 1 d, with almost daily episodes lasting at least 4 weeks, but not more than 1 year.
(iii) No previous history of chronic TD or Ts.
④ onset before the age of 18 years.
⑤ TD symptoms are not directly caused by certain drugs (e.g., stimulants) or medical conditions (e.g., Huntington’s chorea or post-viral encephalitis).
(2) Chronic TD.
(i) One or more motor twitches or vocal twitches that do not occur simultaneously during the course of the disease.
(ii) The twitches occur multiple times a day and may occur daily or with intervals, but the intervals last no more than 3 months and the duration of the disease is more than 1 year.
③ onset before the age of 18 years.
(iv) TD symptoms are not caused by certain drugs (e.g. stimulants) or medical diseases (e.g. Huntington’s chorea or post-viral infection encephalitis).
(3) TS.
(i) Having multiple motor twitches and one or more vocal twitches during the course of the disease, without having to occur at the same time.
(ii) The twitches may occur multiple times a day (usually in clusters) or intermittently, but the interval does not exceed 3 months, and the duration of the twitching disease is more than 1 year.
(iii) The site, number, frequency, intensity and complexity of the twitches vary with time.
(iv) The onset of the disease before the age of 18 years.
⑤ The tic symptoms are not directly caused by certain drugs (e.g., stimulants) or medical conditions (e.g., Huntington’s chorea or post-viral encephalitis).