What is Dystonia?
Dystonia is a condition where muscles involuntarily contract, creating abnormal postures, twisting, repetitive movements, or shaking. These symptoms can occur or worsen when a person tries to move.
Dystonia isn’t constant; its severity can change depending on a person’s activities and posture. It could result in multiple unusual movements like overstretching or over-bending of the hand, the foot turning inward, the head bending sideways or backwards, the spine twisting along with arching and turning of the back, the eyes forcefully closing, or a fixed grimace. The symptoms usually stop when the person is active and during sleep.
The severity of dystonia can greatly vary, and it can fluctuate in the same person. In severe cases, it can cause awkward and distorted movements. The level of severity is different for everyone.
Dystonia is often overlooked or misdiagnosed due to its unpredictable course and diverse symptoms.
Most people with dystonia can lead a relatively normal life, but others might need help with daily activities.
What Causes Dystonia?
Dystonia is a condition that results in abnormal muscle contractions or spasms and it can vary a lot in terms of cause and symptom presentation. There are two main types of dystonia: primary and secondary.
Primary dystonia, which can either run in families or occur sporadically, is a type where dystonia is the only neurological sign, apart from the occasional tremor. In this case, other potential causes, like acquired or neurodegenerative processes, have been ruled out. This form of dystonia can start early in life or appear in adulthood.
There’s a greater genetic influence involved in primary dystonia, with, or without, a family history of the condition. However, the exact cause of primary dystonia remains unclear. It seems, it may be due to a combination of genetic susceptibility and environmental factors.
If primary dystonia starts early in life, it usually first affects an arm or a leg and can then spread, often becoming widespread. This early-onset dystonia is usually associated with two genes: DYT 1 and DYT 6.
However, when primary dystonia appears in adults, it usually affects the neck, head or upper arm muscles and tends to remain localized. It’s important to mention that the most common form of dystonia is the one which affects the neck (cervical dystonia) and, overall, it’s more prevalent than early-onset primary dystonia.
Secondary dystonias, on the other hand, are caused by environmental factors, such as a head injury, side effects of drugs like tardive dyskinesia, or a neurological disease, e.g., Wilson’s disease.
There’s also an intermediate category, termed “dystonia plus syndromes”, which includes disorders where there are no acquired or degenerative causes but there are other neurological symptoms beyond dystonia. This category includes conditions like dopa-responsive dystonia, myoclonus dystonia and rapid-onset dystonia-parkinsonism.
Additionally, it’s worth noting that certain medications may be associated with dystonia, including, examples like antipsychotics, antiepileptics, certain stimulants like amphetamines and cocaine, and even more everyday substances like caffeine or some types of contraceptive pills.
Risk Factors and Frequency for Dystonia
Dystonia is a condition that affects movement and is the third most common of its kind. In North America alone, it impacts around 500,000 adults and children. It’s the most frequent movement disorder seen in clinics, second only to Parkinson’s disease.
Signs and Symptoms of Dystonia
Dystonia is a medical condition where muscles contract involuntarily, causing twisting and repetitive movements or abnormal postures. It can be generally categorized into two different types, idiopathic and symptomatic dystonia.
Idiopathic dystonia is often inherited, might begin subtly and typically emerges during a repeated and specific action. On the other hand, symptomatic dystonia is a result of another condition such as a stroke, tumor, infection, or toxin exposure, among others.
Dystonia can manifest itself in different ways during a clinical examination. For instance, patients may encounter involuntary twisting movements, especially during specific voluntary tasks like walking or writing. Sometimes, painful cramps in hands or uncontrollable head-turnings when watching TV or driving might indicate dystonia.
- Oro-mandibular dystonia can occur as nighttime jaw spasms. This type of dystonia can be caused by dental procedures or facial traumas.
- Spasmodic dysphonia is another form of dystonia that starts as a strained voice. However, the tone of affected areas is usually normal when the condition first starts.
A distinctive type of tremor, known as a dystonic tremor, can sometimes be recognized in patients with dystonia. This tremor might get lesser when the head is held in a certain position, and worsen when the head is turned to a side. This kind of tremor varies in frequency and magnitude and often disappears in sleep.
In the early stages, dystonia may be mistaken for a plain mannerism or considered a psychological issue, and it’s only when the posture abnormalities continue and the typical psychological traits aren’t present that the correct diagnosis may be made. Dystonic movements usually worsen with stress, fatigue, and emotional distress, but they tend to decrease when the person is relaxed or sleeping.
A unique feature of dystonic movements is that they can be relieved by certain sensory tricks. For example, patients with neck dystonia may place a hand on their chin to lessen the contractions, and oro-lingual dystonia can be eased by touching the lips or putting an object in the mouth.
Dystonic movements can last from several seconds to weeks or even months. In some situations, this may lead to permanent bone deformation and impaired function.
Testing for Dystonia
Dystonia, a health condition that causes uncontrolled muscle contractions and subsequent abnormal movements, is diagnosed based on its type and the patient’s symptoms. Professional evaluation and certain genetic tests are fundamental to diagnosing this condition.
In primary dystonia, a clinical evaluation – basically an assessment of symptoms – combined with specific genetic tests can help pinpoint the diagnosis. These tests look for mutations in the genes at the DYT1 and DYT6 locations, which have been linked to Oppenheim dystonia, a specific form of this condition that often starts during childhood or adolescence. It’s most common in the Ashkenazi Jewish population.
Dystonia plus syndrome is another form of this condition, which combines dystonia with Parkinson-like symptoms or sudden-onset dystonia that affects movement. Dopa-responsive dystonia, a subtype, commonly starts between ages six and 16, but can occur at any age. In babies, it can resemble cerebral palsy, while in adults, it can look like Parkinson’s disease. Interestingly, this condition seems to affect girls more often than boys and is not more common in any particular ethnic group. Gene mutations are often the underlying cause of dopa-responsive dystonia.
Secondary dystonia, on the other hand, develops because of environmental factors that impact the brain. It can also be caused by spinal cord injury or peripheral injuries. A history of head trauma, encephalitis, exposure to toxins or drugs, lack of oxygen at birth, or other neurological disorders can be useful in diagnosing this type of dystonia. Health professionals will assess symptoms and may use brain imaging as part of the diagnosis.
Heredodegenerative dystonia is associated with genetic abnormalities that result in neurodegenerations. Its dominant feature is dystonia, seen in neurodegeneration. The patient may need to undergo a brain MRI, blood tests to measure certain enzymes, and eye exams to make a diagnosis. Typically, additional tests like nerve conduction studies or vitamin E level tests may also be required.
Imaging studies may also be crucial to identify any abnormalities in the brain like lesions, or damage due to hemorrhage or lack of oxygen.
Treatment Options for Dystonia
The most effective medicines for treating dystonia include anticholinergics such as trihexyphenidyl, GABA agonists like baclofen and benzodiazepines, and medications that affect dopamine levels. These medications work by changing how certain chemicals are transmitted in the brain, specifically dopamine and acetylcholine, and reducing the effects of another brain chemical, GABA.
Trihexyphenidyl is often the first choice for treating dystonia which starts in childhood and affects most or some parts of the body.
A substance called botulinum toxin can be used to treat focal dystonia, a type of dystonia that affects a single body area. It works by blocking a brain chemical called acetylcholine from getting to the muscle, which weakens the muscle and makes it less active. It is often the first-choice treatment for cervical dystonia (which affects the neck), blepharospasm (which affects the eyes), laryngeal dystonia or spasmodic dysphonia (which affects the voice box), and focal limb dystonia (which affects one limb). Botulinum toxin injections can also reduce afferent feedback from affected muscles which may help to restore normal movement patterns in the brain.
Some individuals with dystonia develop abnormal movements as a reaction to certain drugs, and this requires specialized treatment.
Previously, surgery involving creating lesions in specific parts of the brain was used to treat dystonia, but these procedures sometimes led to lasting, harmful side effects, such as problems with speech. Nowadays, deep brain stimulation (DBS), a procedure that can be adjusted and reversed, is used as a safer alternative. DBS has become a crucial treatment option over the last 20 years for individuals with severe dystonia that hasn’t responded to medication. The procedure involves targeting a part of the brain called the globus pallidus. DBS helps by making functional changes within the abnormal motor networks in dystonia, which helps to normalize the overly active motor activation responses. In contrast to its rapid effect in conditions like Parkinson’s disease or essential tremor, the impact of DBS typically takes longer in dystonia, often weeks to months, as the motor circuit needs time to adjust and adapt to changes brought about by DBS.
However, different patients respond differently to DBS, with some showing considerable improvements while others only having modest benefits or none at all. Currently, there’s no way to reliably predict who will respond best to DBS, and this is an area of ongoing research.
It’s still unclear whether DBS should be used to treat secondary dystonia, a type of dystonia caused by another condition.
Physical therapy may help those with dystonia affecting a certain part or parts of the body. Speech therapists can provide communication aids and techniques to relax the jaw for people with dystonia affecting their speech.
What else can Dystonia be?
- Cerebral palsy
- Lysosomal storage disease, a metabolic disorder
- Neuronal ceroid lipofuscinoses, a group of severe neural disorders
- Neuro acanthocytosis, a rare movement disorder
- Parkinson-plus syndrome, a neurological disorder similar to but more severe than Parkinson’s
- Early onset Parkinson’s disease
- Post-stroke muscle stiffness or spasticity
- Psychogenic dystonia, a movement disorder with psychological origins
- Spinocerebellar ataxia, a genetic disorder that affects movement control
- Systemic lupus erythematosus (SLE), an autoimmune disease
These could be possible conditions a doctor might consider when diagnosing a patient with certain symptoms. Each of these conditions are different from one another and require specific tests in order to confirm the diagnosis. Therefore, it’s critical that doctors consider all possible conditions based on a patient’s symptoms to assure an accurate diagnosis.