What are movement disorders?
Movement disorders are conditions that cause involuntary body movements. With all movement disorders, abnormal signals from the brain cause patients to have trouble controlling their muscles.
There are several different types of movement disorders that affect people in different ways. Dystonia, Parkinson's disease, tics and Tourette syndrome are all movement disorders.
What is dystonia?
Dystonia (say: diss-TOE-nee-uh) is a movement disorder that causes sustained muscle contractions. In a person with dystonia, the muscles tense up, often causing twisting and repetitive movements or abnormal postures. In some children, the movements may be painful. There are several different types of dystonia, each with its own characteristics.
The condition can vary from very mild to severe. Dystonia may get worse over time or it may stay the same or get better.
Some children are born with dystonia. Dystonia may also appear as a child or an adult gets older.
How much of the body and how many muscles are affected by dystonia can vary
In some children, only one part of the body is affected; in other children, several or many parts are affected. How dystonia is treated depends on the type of dystonia, its cause and how severe the case is.
Classifying dystonia
Part of diagnosis is finding out what type of dystonia a child has. This is important because the type of dystonia will help determine which treatments may work best. Also, different types of dystonia will progress in different ways over time.
In general, dystonia is classified based on two factors:
- Clinical features
- Age: how old the child is at the onset of symptoms
- infancy onset: birth to two years old
- childhood onset: between three and 12 years old
- adolescent onset: between 13 and 20 years old
- adult onset: older than 20 years
- Body distribution of the dystonia: where and how much of the body is affected
- focal: only one part of the body, such as the leg, is affected
- segmental: two adjacent parts of the body are affected, such as the head and neck
- hemi-dystonia: different parts on the same side of the body are affected, such as the left hand and left foot
- generalized: multiple parts of the body are affected, such as both arms and one leg
- Course of the disease: how the condition develops over time
- progressive: gets worse over time
- episodic: comes and goes
- static: does not get better or worse over time
- Cause
- Genetic dystonia is caused by an underlying genetic mutation.
- Idiopathic generalized dystonia and dopa-responsive dystonia (DRD or Segawa's disease) are two types of primary dystonia, which are caused by genetic mutation.
- Acquired dystonia is a result of the brain being injured by exposure to a toxin or drug, a stroke, infection, birth injury or other trauma.
Symptoms of dystonia can differ depending on the part of the body that is affected
Posturing due to abnormal muscle contraction can be present in only one region of the body (focal dystonia), such as the leg, the arm or the neck, or it may affect the entire body (generalized dystonia). The following are examples of the ways dystonia affects different parts of the body.
- Cervical dystonia involves the neck and can cause abnormal posturing of the head.
- Limb (upper or lower) dystonia can cause difficulties with walking or fine motor skills, such as those required for writing or playing an instrument.
- Oromandibular dystonia involves the tongue or jaw and can cause slurred speech or chewing or swallowing difficulties, which could lead to reduced food intake and dietary problems.
- Spasmodic dystonia involves the vocal cord and can cause sudden changes in voice pitch and even difficulties breathing.
Dystonia begins in the brain
Like all movement disorders, dystonia is a neurological condition. The problem begins in the brain. The brain sends abnormal signals to muscles in the body. These signals cause the uncontrolled movements.
What causes the brain to send these signals is not fully understood. However, dystonia can have both genetic and other causes.
Sometimes, children with dystonia may also have other neurological problems, such as cerebral palsy.
Course of dystonia
The most common forms of dystonia that develop in childhood are caused by cerebral palsy. Cerebral palsy is a result of non-progressive damage (damage that does not get better or worse) to the developing brain of a fetus or infant. However, there are other forms of dystonia that develop in childhood that could have progressive symptoms. These forms result from genetic conditions. The exact progression of each form will vary depending on the underlying cause.
Diagnosing dystonia
Symptoms of dystonia may appear at any age from young toddlers to older children. Symptoms are usually mild at the beginning and gradually get worse. Very rarely, symptoms appear abruptly and severely.
At first, parents usually notice problems with their child's legs. A child may seem clumsy, and may fall or trip a lot. A child may start walking later than normal and may have trouble keeping up with other kids.
In some children, dystonia progresses though the day; in the morning, they have a surprising amount of control over their muscles, but in the evening the symptoms are more severe.
If your child's doctor suspects your child might have dystonia, your child will be examined by a neurologist. A neurologist is a doctor who specializes in brain, nerve and muscle function. The neurologist will check your child's bones, joints and muscles. Reflexes will also be checked.
Other conditions can also cause symptoms similar to dystonia. To diagnose dystonia, the doctor will need to consider these other conditions.
Treatment of dystonia
How dystonia is treated depends on the type and severity of the condition. There are no treatments to cure dystonia. Treatments target specific symptoms and are intended to relieve muscle spasms, pain and discomfort. Treatment is individualized to each patient — no specific treatment is appropriate for every patient. Children who are still growing need treatment before the dystonia causes permanent bone deformities.
In general, there are three ways to treat dystonia:
- medicines that are taken by mouth
- injections of Botulinum toxin (Botox)
- surgery
Medicines taken by mouth
All medicines for dystonia have side effects, and they must be used carefully according to your doctor's instructions. For more information, please speak to your doctor or pharmacist.
Levodopa and carbidopa
Many children with dystonia are first given a trial of a medicine called levodopa (L-dopa). Levodopa often works well at restoring muscle control for dopa-responsive dystonia (DRD). Some patients with other types of dystonia can also show some improvement with this medicine.
Sometimes, levodopa is combined with a medicine called carbidopa. Both these medicines increase dopamine in the brain. Dopamine is a neurotransmitter that regulates movement.
These medicines may produce side effects such as skin flushing, a drop in blood pressure, nausea, vomiting and diarrhea, among others.
Other oral medicines
Other medicines can also be used to treat dystonia. They include:
- trihexyphenidyl and other anticholinergic (say: an-tee-call-in-URGE-ic) medicines, which act on neurotransmitters
-
baclofen, a muscle relaxant — in children with cerebral palsy, this is often the first line of medication treatment for dystonia
- benzodiazepines, such as clonazepam or diazepam, which act as a muscle relaxant and sedative
In more severe cases, a combination of these medicines may be used.
Injections of Botulinum toxin (Botox)
Most people know that Botox injections can be used to reduce wrinkles. Because Botox works by temporarily paralyzing tissues around an injected area, it can also be used to treat dystonia.
Botox injections are the treatment of choice for most forms of focal dystonia. However, these conditions are not frequently seen in children. In children, botulinum toxin is used in generalized dystonia patients when targeting a certain part of the body. It is often used when there is spasticity as well as dystonia, particularly in the legs. Spasticity means the brain is constantly telling the muscles to tighten or contract.
The effect of Botox injections usually lasts about three to four months. After this, more injections will be needed.
Botox injections are limited in what they can accomplish. If too many places are injected, for example, the child can temporarily lose control of movement altogether.
Surgical treatment of dystonia
If dystonia does not respond to other treatments, the neurologist or developmental paediatrician may suggest a surgical treatment.
Intra-thecal baclofen
Patients with generalized dystonia may be treated with intra-thecal baclofen (ITB). Like the medicines by mouth discussed above, baclofen is a medicine that relaxes muscles by acting on neurotransmitters in the brain.
Intra-thecal baclofen is given through a small tube that is surgically placed into the spine. The tube is attached to a pump that is placed in the soft tissue of the abdominal wall. After the operation, the pump is programmed to deliver a continuous amount of baclofen into the fluid around the spine. The pump can be re-programmed by the doctor to adjust for a child's specific needs.
The treatment can be effective for most people, but for about one in 10 patients (10%), the treatment will stop working within the first year.
Complications of ITB may include:
- infection
- decreased head and neck control
- drowsiness
- leakage of cerebral spinal fluid (CSF)
- catheter or pump malfunction
- baclofen withdrawal
- overdose
These complications can be very dangerous. Patients and families must learn about the signs and symptoms for these complications, so that they can seek medical attention as soon as possible.
Deep brain stimulation
Deep brain stimulation (DBS) is a relatively new treatment for children. It tends to work best on the genetic forms of dystonia but also works in other forms of dystonia.
DBS controls dystonia by putting a small amount of electricity into the brain through tiny electrodes. The electrodes are attached to a battery. The brain is not surgically opened; instead, a tiny hole is made in the skull.
Sometimes, it can take several months for the treatment to become effective. Often, the effect improves over a period of six months to a year.
Complications of DBS may include:
- mechanical problems such as broken wires, displaced electrodes, or battery failure
- infections
- bleeding in the brain
- stroke
These complications can be very dangerous. Patients and families must learn about the signs and symptoms for these complications, so that they can seek medical attention as soon as possible.
Potential complications of dystonia
The complications your child may experience will depend on the type of dystonia they have. Potential complications of dystonia include:
- difficulties performing daily activities or specific tasks (writing, playing an instrument, etc.)
- in severe cases, fixed contraction (tightening) of a joint (wrist, ankle, etc.) or scoliosis
- difficulties chewing and swallowing, which may eventually lead to malnutrition
- depression, anxiety
What to expect in the future
There are many different types of dystonia. There is no one set way the condition progresses. Ask your child's doctor what you can expect.
Typically, when dystonia is diagnosed in a child, the condition can slowly but steadily get worse over time. However, this does not mean that a patient's mental capacity or cognitive abilities will also get worse. In other words, other parts of the nervous system, may or may not be affected.
Take your child to the nearest emergency department if they experience dystonic storm
Dystonic storm is a rare presentation of dystonia that is primarily seen in children with pre-existing motor abnormalities. This usually occurs as a result of an acute illness or after general anaesthesia in a child with a history of dystonia. The child will present with continuous dystonia that can last for a few hours. The child might be diaphoretic (covered with sweat) and in pain. If this occurs, take your child to the nearest emergency department.