I. What is dystonia
Dystonia is a form of involuntary movement with specific manifestations, mostly notable for abnormal expressive postures and involuntary changes of movements. The earliest description of dystonia can be traced back to Tulpius’ description of spastic squint in 1652, and the term deformational dystonia was first introduced by 0ppenheimsh in 1911 to emphasize the characteristics of the changes in muscle tone. However, it was also recognized that the disease is still characterized by abnormal movements, postural torsion, and gradual progression, and may be an inherited, organic lesion, so Flatau & Sterling suggested calling it progressive torsional spasticity. The currently accepted definition of dystonia was proposed by the advisory board of the International Dystonia Medical Research Foundation in 1984: it is a syndrome of twisting, repetitive movements or postural abnormalities caused by involuntary, sustained muscle contractions. It is characterized by involuntary movements and abnormal posture caused by uncoordinated or excessive contraction of the active and antagonistic muscles, which is different from the general sense of increased or decreased muscle tone.
Second, what is the prevalence of dystonia
Foreign primary dystonia survey shows that the prevalence rate is 370/1 million, according to this projection, there are about 3 million people suffering from this disease worldwide, in fact, due to the lack of awareness caused by underdiagnosis or misdiagnosis, the actual number of patients is higher than this. For example, about 1/3 of children with cerebral palsy can have dystonia, and about 1/3 of patients with Parkinson’s disease can have dystonia during the course of the disease.
Third, how is dystonia classified
At present, dystonia can be classified according to the age of onset, clinical manifestations, etiology, genetic basis, drug response and other factors, and the most commonly used clinical typology is as follows.
(A) According to the age of onset
(1) Early onset: ≤26 years old, with peak onset around 9 years old, usually with symptoms in the lower or upper extremities first, often progressing to involve other parts of the body.
2. Late onset: >26 years old, with peak onset around 45 years old, symptoms often involve facial, pharyngeal and neck or upper limb muscles first, and tend to maintain their focal or limited involvement of adjacent muscles.
(B) Typing according to the distribution of symptoms
1.Focal type: single site muscle groups are involved, such as blepharospasm, writing spasm, spasmodic dysarthria, spasmodic slant neck, etc.
2.Segmental type: 2 or more adjacent muscle groups are involved, such as craniocervical dystonia (Meige syndrome), axial dystonia, etc.
3.Multifocal type: 2 or more non-adjacent muscle groups are involved.
4.Generalized type: combination of lower limb and any other segmental dystonia, such as torsional spasm.
5.Eccentric type: half of the body is involved, usually secondary to dystonia, often due to damage to the contralateral hemisphere, especially the basal ganglia.
(C) According to the etiology of the typology
1.Primary or idiopathic: Dystonia is the only abnormal clinical manifestation without known etiology or other genetic degenerative diseases, such as DYT-1, DYT-2, DYT-4, DYT-6, DYT-7, DYT-13 dystonia.
2.Dystonia superimposed: Dystonia is one of the main clinical manifestations, but it is related to other movement disorder diseases without evidence of neurodegenerative diseases, such as DYT-3, DYT-5, DYT-11, DYT-12, DYT-14, DYT-15 dystonia.
3, genetic degenerative disease: dystonia is one of the main clinical manifestations, accompanied by other features of a genetic degenerative disease, such as wilson’s disease, crestal cerebellar ataxia, Huntington’s chorea, Parkinson’s syndrome, etc.
4.Episodic dystonia: It is a sudden and recurrent movement disorder with normal interictal performance.
According to the different triggering factors, there are three main forms.
(1) ictal onset-induced dyskinesia (PKD, DYT-9), which is induced by sudden movements.
(2) episodic hyperkinesis-induced dyskinesia (PED, DYT-10), which is induced by continuous movement such as running or swimming.
(3) episodic non-motor-induced dyskinesia (PNKD, DYT-8), which can be induced by drinking alcohol, tea, coffee or hunger, fatigue, etc.
(5) Secondary or symptomatic: Dystonia is a symptom of other known neurological diseases or injuries with various etiologies, such as after traumatic brain injury, after intracranial infection, exposure to certain drugs or chemical toxins, etc.
The following clinical clues are often suggestive of secondary dystonia.
(1) sudden onset and rapid progression early in the course of the disease.
(2) Persistent eccentric-type dystonia.
(3) Early onset of fixed postural abnormalities.
(4) The presence of neurological signs other than dystonia.
(5) early onset of significant medullary dysfunction, such as dysarthria, stuttering and dysphagia
(6) Mixed movement disorders, i.e., dystonia superimposed on Parkinson’s disease, myotonia, myoclonus, choreographic movements, and other movements.
(7) Progressive dystonia of a single limb in adults.
(8) Adult-onset generalized dystonia.
Fourth, when what symptoms appear, we suspect dystonia?
Dystonia is a kind of involuntary movement with special manifestations, mostly notable for abnormal expression posture and involuntary change of movement.
The clinical manifestations of dystonia are complex and variable: the motor involvement can spread to the muscles of the whole body, and the clinical manifestations of patients vary greatly depending on the location and extent of the affected muscles and the strength of the abnormal contractions, such as blepharospasm, spastic squint, writing spasm, spastic dysarthria, and generalized twisting spasm.
The course of dystonia is often progressive and fluctuating, and the same patient may have different clinical manifestations at different stages of the course of the disease.
However, certain characteristic manifestations can help the diagnosis of dystonia.
1, the speed of involuntary movements in dystonia can be fast or slow, can be irregular or rhythmic, but there is a short duration in the peak state of contraction, presented as a strange action or special posture.
2. Involuntary movements easily involve the head and neck muscles, trunk muscles, limbs of the anterior rotators, finger and wrist flexors, toe extensors, etc.
3, the interval between episodes is variable, but the direction and pattern of abnormal movements are almost constant, the muscle groups involved are more constant, and the muscle strength is not affected.
4. The involuntary movements are aggravated during random movements and reduced or disappeared during rest and sleep, which may show progressive aggravation.
5. Early in the course of the disease, the symptoms may improve unexpectedly due to some sensory stimulation, which is called “sensory trickery”. For example, touching the lower jaw or lightly supporting the head in patients with spastic diagonal neck can restore the normal position of the distorted head. Sometimes random movements may also suppress dystonia, usually in the face and mouth-mandibular region, for example, singing or chewing can reduce blepharospasm, which is considered a form of sensory trickery. As the disease progresses, the symptoms gradually tend to be constant, even forming a fixed spastic deformity, and the sensory trickery disappears.
6. Symptoms are often aggravated by mental tension, anger, and fatigue.
V. Congenital squint and spastic squint have similar symptoms, how to distinguish them?
The so-called congenital squint refers to the deformity that the neck is tilted to one side after birth, among which those caused by muscle lesions are called myogenic squint; those caused by bone development deformity are called osteogenic squint. The latter is very rare, but congenital squint is a group of conditions in which the newborn has contracture of the sternocleidomastoid muscle on one side, resulting in an asymmetric deformity of the head and jaw, with the head tilted to the affected side, the jaw turned to the healthy side, and unfavorable head movement. The diagnosis of this disease is relatively easy, and can be confirmed when the child sees a palpable, muscular mass in the upper, middle or lower part of the sternocleidomastoid muscle with head and neck tilt deformity a few days to a month after birth.
Spastic squint is an organic disorder of the extrapyramidal system characterized by twisting or paroxysmal tilting of the cervical muscles. It usually occurs in adults aged 30 to 50 years. The clinical manifestations are slow onset and manifest as involuntary contractions of the neck muscles, resulting in involuntary rotation of the head to one side and flexion of the neck to the other side, which can be aggravated by emotional stress.
The disease is variable, ranging from mild or occasional to difficult to treat. The disease can last a lifetime and can lead to restrictive motor deficits and postural deformities. The course of the disease usually progresses slowly and is stagnant after 1 to 5 years. Some patients (about 5%) can spontaneously heal within 5 years after onset, usually in younger onset, milder patients.
VI. Besides congenital squint, what other diseases should dystonia be distinguished from?
Dystonia is also distinguished from the following diseases.
1, psychosomatic disorders caused by dystonia: characterized by often appearing at the same time with sensory discomfort, fixed posture, no sensory trick utility, better when no one observes, psychotherapy, self-relaxation and clear nature of the disease can be improved or even cured.
2, organic pseudo-dystonia: ocular infection, dry eye and ptosis should be distinguished from blepharospasm; dental closure or tonomandibular joint lesion should be distinguished from oromandibular dystonia; cervical spine bone and joint deformity, forced head position due to trauma, pain or vertigo, congenital cervical muscle strength asymmetry should be distinguished from spastic squint.
7.What factors can cause dystonia?
The etiology of dystonia is diverse: dystonia is a group of heterogenous diseases, which can be the prominent or only symptom of independent diseases, such as primary or idiopathic spastic squint, blepharospasm, torsion spasm, etc.; or it can be one of the concomitant symptoms of various other neurological diseases, such as cerebral palsy, traumatic brain injury, genetic metabolic diseases, diseases caused by drug or chemical poisoning, neurodegenerative diseases, etc., i.e. symptomatic or Secondary dystonia; or other non-neural tissue or organ lesions that cause abnormal movements or postures that appear to be dystonia, such as abnormal head and neck postures caused by strabismus, i.e., pseudo-dystonia. Psychogenic movement disorders (or conversion disorders) also often have dystonia-like manifestations.
Eight, what is the prognosis of dystonia?
The prognosis of patients with dystonia varies greatly. Generalized dystonia can often progress slowly, mainly manifesting as involuntary movements and varying degrees of random movement disorders. Although not directly life-threatening, abnormal postures and expressions often put patients in an embarrassing and helpless situation, and in severe cases, they lose the ability to work and take care of themselves.
Doppler reactive dystonia, episodic dystonia, and adult focal dystonia can often maintain a basic normal functional state with appropriate treatment.
What are the current treatments for dystonia?
The current treatment for dystonia mainly includes general treatment, etiology treatment, symptomatic treatment and surgical treatment.
General treatment includes psychotherapy, functional exercise and Chinese massage and physiotherapy, which are applicable to all patients with dystonia and are the basic elements of clinical treatment.
Etiological treatment is mainly for the specific causes of secondary dystonia. Symptomatic treatment is still the key element in the current treatment of dystonia.
Symptomatic treatment includes.
1, the choice of traditional oral medications: in general, the efficacy of exploratory oral medications for dystonia varies from person to person and often has no definite, lasting effect. Most drugs have mild or transient effects, and motor symptoms may improve at higher doses, but systemic toxicities may occur that are not tolerated by patients, such as drowsiness, unresponsiveness, dry mouth, gastrointestinal discomfort, and emotional abnormalities.
2.Application of local injection of botulinum toxin: local injection of botulinum toxin mainly treats focal dystonia, which can relax the target muscles through selective chemical denervation and rebuild the balance of power between active and antagonistic muscles to reduce symptoms, correct posture, improve and enhance motor ability.
For segmental or generalized dystonia, local injections of botulinum toxin can effectively control the most prominent symptoms and can be used as a complement to other treatments.
However, in the process of implementation, there are high requirements for the operator in terms of indications, dose selection, target muscle positioning, complication prevention and other treatment skills, and repeated injections are needed to maintain the efficacy, frequent additional injections may lead to antibody production, the dose used in clinical practice is limited by safety, and it is not feasible if the affected muscles are extensive, and it is difficult to restore complete normalcy to some complex motor dysfunction. It is also difficult to restore some complex motor dysfunction to normal.
3, the choice of surgical treatment: for particularly severe or conservative treatment is not effective in patients with dystonia can consider suitable surgical treatment.
Traditional peripheral surgical treatment has certain efficacy, but the trauma is obvious, and there are quite a number of cases of recurrence. Deep brain electrical stimulation (DBS) has been applied to the treatment of various dystonia disorders, and it has been reported that primary dystonia symptoms can be improved by 40% to 90% after DBS implantation, while secondary dystonia symptoms do not improve as much as primary ones.
The response of dystonic movements to treatment with continuous DBS may be delayed relative to Parkinson’s disease symptoms. Fixed dystonic postures may take up to several months to a year or more to gradually improve after surgical treatment.DBS surgery has become the treatment of choice for patients with refractory dystonia. Although DBS is less destructive than stereotactic disruption, certain complications and side effects can still occur. These problems can arise from the procedure itself (hematoma), the components (displacement, fracture, infection), or target-related side effects (various neurological and psychiatric signs and symptoms).
IX. What do we have to do to achieve prevention of dystonia?
With the development of molecular biology, the role of genetic factors in the pathogenesis of dystonia has received increasing attention. For these diseases with genetic background, prevention becomes more important. Preventive measures include avoiding consanguineous marriage, promoting genetic counseling, carrier genetic testing and prenatal diagnosis and selective abortion to prevent the birth of affected children. Early diagnosis, early treatment, and enhanced clinical care are important to improve the quality of life of patients. For secondary dystonia, the key is to prevent the factors that lead to the primary disease.
Dystonia is a movement disorder with a prevalence second only to Parkinson’s disease, and has long been neglected due to its complex etiology, unclear mechanisms and lack of effective treatments. In the last decade, due to the progress of genetic research and the emergence of some effective treatment methods, dystonia has become a hot spot for basic and clinical research, which also brings hope to the majority of patients. Currently, DBS surgery can be considered for patients with refractory dystonia, especially primary dystonia (DYT1), delayed dystonia in secondary dystonia, post-traumatic brain injury dystonia, myoclonus-dystonia syndrome, Hallerroden-Spatz disease, abdominal anomalies, and neurospinal erythrocytosis.