What is it ?
Dystonia is a disorder that is characterized by involuntary muscle contractions resulting in repetitive movements and abnormal postures. It refers to both a symptom and a group of diseases with multiple causes and complex classifications, controversial and evolving as scientific advances. Dystonia, as a symptom, can be very disabling and very painful. It affects around 45,000 people in France, according to the Association of People with Dystonia.
Symptoms of dystonia
Muscle contractions may be prolonged or intermittent. They cause dystonic movements that are usually twisting and distorting movements. These involuntary movements may be accompanied by tremors. It should be emphasized, however, that dystonia is not an obsessive-compulsive disorder , nor is it a Tic.
Dystonias are classified according to the areas of the body that they affect: focal, segmented, multifocal, and generalized. Cervical focal dystonia is the most common dystonia. It is also called spasmodic torticollis because it causes uncontrolled movements of the head.
The origins of the disease
Dystonia is due to central nervous system disorders, but its underlying causes (and mechanisms) are still poorly understood. They could be due to abnormalities affecting areas of the brain. Imbalances in neurotransmitters (transmitting nerve impulses between neurons) may also be involved. Most cases of dystonia would develop due to a combination of genetic and environmental factors. A dystonia can have multiple origins and one distinguishes three big groups of dystonias according to their origin:
- Idiopathic dystonia, the underlying causes of which are not identified.
- Acquired (or secondary) dystonia resulting from infection, drug exposure, brain damage (birth injury due to lack of oxygen, tumor, stroke, hemorrhage) .
- Genetic dystonias, caused by mutations in several genes, are often sporadic but sometimes hereditary. They declare themselves in generalized form, often from childhood or adolescence.
Risk factors for dystonia
Many genetic diseases can be associated with dystonia (Huntington’s disease, Wilson’s disease, …). Moreover, the term pseudo-dystonia is misused to designate diseases that resemble dystonia such as Chiari malformation or Dupuytren’s disease.
Prevention and treatment of dystonia
There is no curative treatment and symptomatic treatments are adapted to each particular form of dystonia. Botulinum toxin injections are the most effective treatment for reducing muscle spasms and relieving pain, by blocking the release of a neurotransmitter responsible for muscle contraction, acetylcholine. Botulinum toxin therapy is effective in particular for treating focal dystonias, such as cervical dystonia and laryngeal dystonia. Several drugs are sometimes prescribed to inhibit the neurotransmitters GABA and acetylcholine, but they are not specific to the treatment of dystonia and are accompanied by side effects.
When these treatments do not relieve the patient, the use of several types of surgery is possible. Among them, deep brain stimulation, which involves surgically implanting electrodes in specific regions of the brain and an electrical pulse generator to interfere and block the electrical signals responsible for the symptoms. Finally, other therapeutic approaches such as speech therapy and physiotherapy should not be neglected to improve stress management caused by the condition.