"Surgical treatment by means of deep brain stimulation is very effective in the treatment of different forms of dystonia".
DR. ICIAR AVILES OLMOS
SPECIALIST. NEUROLOGY DEPARTMENT
Dystonia is characterized by involuntary, sustained or intermittent muscle contractions that cause repeated twisting movements and/or abnormal postures that are produced by the simultaneous muscle contraction of agonist and antagonist muscles.
At the beginning of the symptomatology, the movements appear when making voluntary movements (action dystonia) and it is relatively controllable in a voluntary way. Later the dystonia also appears in rest (dystonic postures) causing deformity of the joints and pain.
Dystonia can affect any body area, but it usually follows a different topography of onset according to the age of onset of symptoms. In adulthood the most common forms affect the face, neck (focal dystonia) and usually do not have a progressive course. The dystonia of initiation in childhood, usually begins by the lower extremities and has a progressive course affecting in a few years most of the body areas (generalized dystonia). These generalized forms usually have a genetic origin.
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What are the symptoms of dystonia?
- Excessive muscle contraction affecting a part or parts of the body
- Appearance of abnormal or sustained postures that improve with rest and disappear with sleep. In many cases dystonic postures can produce joint pain and deformity.
- The performance of voluntary movements with the body part affected by dystonia produces the appearance of dystonic movements in distal regions (for example, appearance of dystonia in a foot when performing voluntary movements with a dystonic hand). This phenomenon is known as "overflow".
- The existence of an antagonistic gesture or sensory trick. It is frequent in patients with focal dystonias such as cervical dystonia or blepharospasm. It consists of certain gestures (such as touching the chin or eyebrows) that significantly reduce the intensity of the dystonia.
Although the predominant symptom is dystonia (isolated dystonia) in many cases dystonia co-exists with another type of movement disorder (combined dystonia) the most common being tremor. The progression of dystonia is variable from one case to another.
In general, focal dystonias that start in adulthood tend to stabilize after a few years without a generalization of symptoms (benign course). In the case of children it often starts in one leg and the tendency is that these contractures progressively affect other areas of the body until they become generalized.
Do you have any of these symptoms?
You may have a dystonia
Types of dystonia by location
Dystonia can have any body distribution. The most frequent are:
1.- Focal Dystonia: It affects only one part of the body and is more frequent in adults.
- The most frequent focal dystonia in adults is cervical dystonia (torticollis), which is characterized by cephalic rotation to one side, in the axial plane. In many cases it starts as a cephalic tremor. Unlike other focal dystonias, it is accompanied by pain in a significant percentage of cases. In almost all cases there is an improvement in dystonia with the performance of an antagonistic gesture. The association with tremor (hands or cephalic) is frequent.
- Blepharospasm is a focal dystonia characterized by intermittent or sustained contraction of the orbicularis oculi muscles that causes in many cases an involuntary and sustained closure of the eyes. Light and wind are factors that aggravate the symptoms. Generally, the spasms are not painful but there may be a feeling of dryness in the eye. In some cases the blepharospasm is associated with involuntary movements of the oromandibular musculature (Meige's syndrome) that can interfere with the articulation of the language.
- Laryngeal dystonia. It is a form of dystonia that appears exclusively when speaking in the usual tone of conversations and is produced by an abnormal contraction of the muscles that regulate the opening and closing of the vocal cords. A characteristic feature is that subjects can sing or speak in a low tone without difficulty.
- Occupational dystonia. They occur only when performing a specific motor activity. The scribe's cramp is the most frequent occupational dystonia, affecting the hand and forearm muscles and appearing exclusively during writing, while the rest of manual activities are not impeded. Other occupational dystonias include musician's, tennis player's or golfer's dystonia.
2.- Generalized dystonia. It is more frequent in children. It tends to start in the legs and progresses upwards to the trunk, which tends to twist, and to other regions of the body until it becomes generalized. It is also called torsion dystonia.
What are the causes of dystonia?
Dystonia is due to a functional or structural alteration of the central nervous system that causes the malfunctioning of the brain circuits that control movement. We can differentiate them in the primary and secondary dystonias:
The primary or idiopathic ones are those genetic hereditary or idiopathic forms in which another disease or responsible agent has not been identified. There have been identified a number of genes associated to different forms of dystonia presentation.
In the literature these forms of dystonia are described as DYT followed by a number; of which there are at least 27 different forms identified (DYT-1 to DYT27). Some of them manifest with isolated dystonia and in other cases there is a combination of dystonia with another type of movement disorder (combined dystonia).
To this group of dystonias belong also the paroxysmal dystonias in which dystonia appears episodically, lasts a certain time (from minutes to hours) and patients are asymptomatic between two consecutive episodes. In some cases there are precipitating factors of dystonia such as exercise, fasting, or the intake of tea or coffee.
Secondary dystonias are those whose cause is related to other factors such as drugs, focal structural lesions of the brain, metabolic alterations (consider alteration of the metabolism of copper, such as Wilson's disease, or of iron and alteration of the metabolism of dopamine), autoimmune diseases (such as encephalitis or multiple sclerosis) or degenerative diseases such as Huntingon's disease or parkinsonism by mutation in PARK2.
How is dystonia diagnosed?
The diagnosis of dystonia is clinical. It is based on the symptoms and signs that the patient presents and its evolution. Along with the collection of possible triggers and personal and family history, a specialized neurological examination must be performed.
The performance of an electromyographic study will show the characteristic pattern of the dystonias with a simultaneous contraction of agonist and antagonist muscles.
In order to know the origin of dystonia, analytical studies should be performed, which in subjects under 50 years old should include determination of copper and ceruloplasmin in blood and iron metabolism and a brain MRI. In most cases it is necessary to perform a genetic study.
How is dystonia treated?
Currently, we do not have a curative treatment for dystonia. It is a chronic process that requires a personalized treatment according to its intensity, location and interference with the person's activity. Oral medications in general provide limited improvement. The most used are clonazepam, tetrabenazine, anticholinergics and some neuroleptics.
It is advisable to always perform a levodopa treatment in young patients and children with focal dystonia of the lower extremities that hinders walking, in the possibility that the subject has a levodopa-sensitive dystonia. In these cases the response to the medication is a diagnostic test
Botulinum toxin. Local infiltration with botulinum toxin of the involved muscles is the treatment of choice in focal dystonia, usually with excellent results and minimal side effects.
The infiltrations must be repeated every 3.4 months and in some cases a loss of efficacy is developed due to the development of neutralizing antibodies.
Surgical treatment by means of deep cerebral stimulation with electrodes implanted in the internal pale balloon. It is the treatment of choice, in the generalized dystonia, as well as in the cervical dystonia that does not respond to infiltration with botulinum toxin and in the dystonia secondary to drugs. The results reported in different studies are satisfactory and the improvement is maintained over time. It is indicated when oral or continuously infused drugs are not effective.
Surgical success is related to the adequate selection of the candidate, the good placement of the electrode in the precise area of the brain and the choice of optimal stimulation parameters.
Where do we treat it?
IN NAVARRE AND MADRID
The Department of Neurology
of the Clínica Universidad de Navarra
The Neurology Department has extensive experience in the diagnosis and multidisciplinary treatment of neurological diseases.
We offer a diagnosis in less than 72 hours, along with a proposal for personalized treatment and post-consultation follow-up of the patient by our specialized nursing team.
We have the most advanced technology for an accurate diagnosis with cutting-edge equipment such as HIFU, deep brain stimulation devices, video EEG, PET and epilepsy surgery, among others.
Why at the Clinica?
- State-of-the-art diagnostic assistance with great work in research and teaching.
- Specialized nursing team.
- We work together with the Sleep Unit.