Dystonias are a group of neurological conditions.
For some, the whole body may be involved in the movements, but for others, only certain parts of the body are affected. Sometimes, dystonia symptoms are linked to specific tasks, such as writing, as in writer's cramp.
Contents of this article:
- Dystonia is not a single condition, but a range of disorders.
- There are many causes of dystonia, including medications, oxygen deprivation, and Huntington's disease.
- Diagnosis will likely involve a range of tests and imaging techniques.
- Treatment depends on the type of dystonia but might include medication, physical therapy, and surgery.
What is dystonia?
Although dystonia is a neurological (brain and nerves) condition, experts say that cognitive abilities (intelligence), memory, and communication skills are not affected.
Dystonia tends to be a progressive condition, but this is not always the case.
Dystonia may be inherited, and one gene that plays a role has been identified.
However, there are other causes, for instance, some people develop dystonia as a result of taking certain medications. Some diseases, such as some forms of lung cancer can also produce signs and symptoms of dystonia.
Treatment may include dopamine or sedative-type medications; sometimes, surgery can help.
According to the American Association of Neurological Surgeons, dystonia affects up to 250,000 people in the United States. They suggest that it is the third most common movement disorder behind essential tremor and Parkinson's disease.
Although most cases of dystonia start in people aged 40-60, it can affect all age groups.
Symptoms of dystonia
The symptoms of dystonia vary from mild to severe and can impact different parts of the body. The early symptoms include:
- foot cramps
- a "dragging leg"
- uncontrollable blinking
- difficulty speaking
- involuntary pulling of the neck
Signs and symptoms vary depending on the type of dystonia they have. Below are some common examples:
Cervical dystonia, also known as torticollis, is the most common form. It affects only one body part and generally starts later on in life. The neck muscles are affected most. Symptoms can include:
- twisting of the head and neck
- pulling forward of the head and neck
- pulling backward of the head and neck
- pulling sideways of the head and neck
Cervical dystonia can produce mild to severe symptoms. If muscle spasms and contractions are frequent and severe enough, the individual may also experience stiffness and pain.
Blepharospasm affects the musculature of the eye.
The muscles around the eyes are affected. Symptoms might include:
- photophobia (sensitivity to light)
- irritation in the eye(s)
- excessive blinking, often uncontrollable
- eyes close uncontrollably
People with severe symptoms may find it impossible to open their eyes for several minutes.
The majority of people with blepharospasm find that symptoms worsen as the day progresses.
Dopa-responsive dystonia primarily affects the legs. Onset occurs from ages 5-30. This type of dystonia responds well to levodopa, a dopamine medication.
The most common symptom is a stiff, unusual walk, with the sole of the foot bent upwards. In some cases, the foot may turn outwards at the ankle.
The individual experiences spasms in the muscles on one side of the face. Symptoms may be more prominent when the individual is under mental stress or physically tired.
The muscles in the voice box (larynx) spasm. People with laryngeal dystonia may sound very quiet and breathy when they speak, or strangled - depending on which way the muscle spasms (in or out).
This type of dystonia affects the jaw and mouth muscles. The mouth can pull outwards and upwards.
Some individuals will only have symptoms when the muscles of the mouth and jaw are being used, while others may experience symptoms when the muscles are not in use. Some individuals may have dysphagia (problems swallowing).
Writer's cramp involves uncontrollable cramps and movements in the arm and wrist; this is a task-specific dystonia because it affects people who do a lot of writing before symptoms appear.
Other task-specific dystonias
- musician's cramp
- typist's cramp
- golfer's cramp
Generalized dystonia normally affects children at the beginning of puberty. Symptoms generally occur in one of the limbs and eventually spread to other parts of the body.
- Muscle spasms.
- An abnormal, twisted posture, due to contractions and spasms in the limbs and torso.
- A limb (or foot) may turn inwards.
- Parts of the body may suddenly jerk rapidly.
In this rare version of dystonia, muscle spasms and abnormal body movements only happen at specific moments.
A paroxysmal dystonia attack can look like epilepsy during a seizure (fit). However, the individual does not lose consciousness and will be aware of their surroundings, unlike epilepsy. An attack can last for just a few minutes, but in some cases, may persist for several hours. The following triggers may bring on an attack:
- mental stress
- tiredness (fatigue)
- consuming alcoholic beverages
- consuming coffee
- a sudden movement
Types of dystonia
Dystonia can be classified according to its underlying cause:
Primary dystonia - not related to another condition. No cause can be identified.
Secondary dystonia - related to genetics, a neurological change, or an injury.
Dystonia is also defined according to the body part(s) affected:
- Focal dystonia - only one part of the body is affected.
- Segmental dystonia - affects two or more connected regions of the body.
- Multifocal dystonia - at least two unconnected regions of the body are affected.
- Generalized dystonia - both legs and other regions of the body are affected.
- Hemidystonia - half of the entire body is affected.
Causes of dystonia
The causes of dystonia depend on whether it is primary or secondary.
Causes of primary dystonia
In primary dystonia, no underlying cause is identified. Experts believe it may be a problem with a part of the brain called the basal ganglia. This region is responsible for involuntary movements.
It may be that not enough, or the wrong types of neurotransmitters are produced in the basal ganglia, resulting in primary dystonia symptoms. It is also possible that enough is produced, but not the right type for proper muscle function. Researchers believe that other brain regions are also involved.
Some types of dystonia are linked to faulty genes.
Causes of secondary dystonia
This type of dystonia is caused by a combination of various conditions and diseases; for example:
- brain tumors
- carbon monoxide or heavy metal poisoning
- oxygen deprivation
- cerebral palsy - in some cases, dystonia is a symptom of cerebral palsy
- Huntington's disease
- MS (multiple sclerosis)
- some infections, such as encephalitis, TB (tuberculosis), or HIV
- traumatic brain or spine injury
- Wilson's disease
Parkinson's disease is also a neurodegenerative condition that affects the same part of the brain as dystonia - the basal ganglia. Because of this, both conditions can sometimes appear in the same individual.
Drug induced dystonia
Certain drugs can cause dystonia. Cases of drug-induced dystonia normally occur after just one exposure to a drug. In general, this is relatively easy to treat successfully.
However, sometimes, dystonia can develop after taking a drug for some time, this is called tardive dystonia; Tardive dystonia is most commonly caused by drugs called neuroleptics, which are used to treat psychiatric, gastric, and movement conditions.
Drugs that can cause drug-induced dystonia include:
- acetophenazine (Tindal)
- loxapine (Loxitane, Daxolin)
- piperacetazine (Quide)
- thioridazine (Mellaril)
- trifluoperazine (Stelazine)
- trimeprazine (Temaril)
Diagnosis of dystonia
Diagnosing dystonia may involve an MRI scan.
A visual examination of the physical signs is a major part of diagnosing dystonia.
However, the doctor will need to carry out some tests and ask targeted questions to determine whether they have primary or secondary dystonia.
Initially, a doctor will examine the medical and family history.
The following tests and procedures can help to determine what type of dystonia they have:
Blood and urine tests - to determine whether there are any toxins or infections, and to check organ function (such as the liver).
Genetic test - to check for faulty (abnormal, mutated) genes and rule out other conditions, such as Huntington's disease.
MRI scan - to reveal brain damage or a tumor.
Levodopa - if symptoms improve rapidly after taking levodopa, the doctor will most likely diagnose early-onset dystonia.
Medication treatments for dystonia
The following are common treatments for dystonia:
People diagnosed with dopa-responsive dystonia will be prescribed levodopa treatment. This medication raises levels of dopamine - a neurotransmitter. People taking levodopa may initially experience nausea, which should ease and disappear after the body gets used to the drug.
This powerful poison, which is safe when administered in very small doses, is often used as a first-line treatment for most other types of dystonia. It prevents specific neurotransmitters from reaching the affected muscles, preventing spasms.
Botulinum toxin is administered by injection. One dose usually lasts about 3 months. There may be some initial (temporary) pain at the injection site.
These medications block the release of acetylcholine, a neurotransmitter known to cause muscle spasms in some types of dystonia. Anticholinergics may not always work.
Muscle relaxants are usually prescribed if other treatments have not been effective. They raise the levels of GABA (gamma-aminobutyric acid), a neurotransmitter that relaxes muscles. Examples of muscle relaxants include diazepam and clonazepam. The medication can be administered by mouth or by injection.
Physical therapy for dystonia
The following are common physical therapy treatments for dystonia.
Sometimes, symptoms can be relieved by touching the affected part of the body, or a body part near to it. Individuals with cervical dystonia may find that if they touch the back of their head or the side of their face, symptoms improve or go away completely.
Splints and braces may sometimes be used as part of a sensory trick therapy.
A physical therapist can also help them improve their posture. Good posture helps protect and strengthen muscles and tissues. Good posture may be achieved with an exercise program, and/or the use of braces.
Surgery for dystonia
If other therapies have not been effective, the doctor may recommend surgery. Surgical procedures for dystonia include:
Selective peripheral denervation
Selective peripheral denervation is sometimes used for people with cervical dystonia. The surgeon makes an incision in the neck before cutting some of the nerve endings that are connected to affected muscles. After surgery, there is likely to be some loss of feeling in their neck.
Deep brain stimulation
Small holes are drilled into the skull. Tiny electrodes are threaded through the holes and placed in the globus pallidus, a part of the basal ganglia.
A small pulse generator is connected to the electrodes. The pulse generator is implanted under the skin, usually in the chest or lower abdomen. The pulse generator emits signals to the globus pallidus, which help block the abnormal nerve impulses produced by the basal ganglia.
There is not much information on the long-term beneficial or detrimental effects of deep brain stimulation because it is a fairly new technique. Deep stimulation results take time; it can sometimes be months before the effects become apparent.