Dystonia in children
Dystonia is a
movement disorder in which a person's muscles twitch uncontrollably. The
contraction causes the affected body part to twist involuntarily, resulting in
repetitive movements or abnormal postures. Dystonia can affect one muscle, a
group of muscles, or the entire body. Dystonia affects about 1% of the
population and women are more prone to it than men.
What are the symptoms of dystonia?
Symptoms of dystonia
can range from very mild to severe. Dystonia can affect different parts of the
body, and often the symptoms of dystonia progress in stages. Some early
symptoms include:
- A "dragging leg"
- Cramping of the foot
- Involuntary pulling of the neck
- Uncontrollable blinking
- Speech difficulties
Stress or fatigue can
cause symptoms or make them worse. People with dystonia often complain of pain
and exhaustion from constant muscle contractions.
If symptoms of
dystonia begin in childhood, they usually first appear in the foot or hand. But
then they quickly spread to the rest of the body. However, after adolescence,
the rate of progression tends to slow down.
When dystonia appears
in early adulthood, it usually starts in the upper body. Then there is a slow
progression of symptoms. Dystonias that begin in early adulthood remain focal
or segmental: they affect either one part of the body or two or more adjacent
parts of the body.
What causes dystonia?
Most cases of
dystonia do not have a specific cause. Dystonia appears to be related to a
problem in the basal ganglia. This is the area of the brain that is responsible
for triggering muscle contractions. The problem is how nerve cells communicate.
Acquired dystonia
occurs when the basal ganglia are damaged. Damage can result from:
- Brain trauma
- Stroke
- Tumor
- Oxygen deprivation
- Infection
- Drug reactions
- Poisoning caused by lead or carbon monoxide
Idiopathic or primary
dystonia is often inherited from parents. Some carriers of the disease may
never develop dystonia. And symptoms can vary greatly among members of the same
family.
Are there different types of dystonia?
Dystonias are
classified depending on which part of the body they affect:
- Generalized dystonia affects most of or all of the body.
- Focal dystonia affects just a specific body part.
- Multifocal dystonia affects more than one unrelated body part.
- Segmental dystonia involves adjacent body parts.
- Hemidystonia affects the arm and leg on the same side of the body.
Dystonias can also be
classified as syndromes based on their patterns:
- Blepharospasm is a type of dystonia that affects the eyes. It usually
starts with uncontrollable blinking. At first, only one eye is usually
affected. However, both eyes are eventually affected. Spasms cause the eyelids
to close involuntarily. Sometimes they even make them stay closed. The person
may have normal vision. But this constant closing of the eyelids renders the
person functionally blind.
- Cervical dystonia, or torticollis, is the most common type. Cervical
dystonia usually occurs in middle-aged people. However, it has been reported in
people of all ages. Cervical dystonia affects the muscles of the neck, causing
the head to turn or lean forward or backward.
- Cranial dystonia affects the muscles of the head, face and neck.
- Oromandibular dystonia causes spasms of the muscles of the jaw, lips and
tongue. This dystonia can cause problems with speech and swallowing.
- Spastic dystonia affects the muscles of the throat responsible for
speech.
- Tardive dystonia is caused by a reaction to a drug. Symptoms are usually
temporary and can be treated with medication.
- Paroxysmal dystonia is episodic. Symptoms appear only during attacks. The
rest of the time the person is normal.
- Torsion dystonia is a very rare disease. It affects the entire body and
seriously incapacitates the person who has it. Symptoms usually begin in
childhood and worsen with age. Researchers have found that torsion dystonia can
be inherited, caused by a mutation in the DYT1 gene.
- Writer's spasm is a type of dystonia that occurs only when writing.
Affects the muscles of the hand and/or forearm.
How is dystonia treated?
There are several
treatment options for dystonia. The doctor will determine the course of
treatment depending on the type of dystonia and its severity.
A recently introduced
treatment is botulinum toxin, also called Botox or Xeomin. The toxin is
injected into the affected muscle. There, it blocks the action of the chemical
acetylcholine that causes muscle contractions. The injection should be repeated
approximately every three months.
When dystonia makes
someone disabled, deep brain stimulation is possible. With deep brain
stimulation, an electrode is implanted in a specific area of the brain. It is
then connected to a battery-powered stimulator implanted in the chest. The
electrode transmits the electrical impulses created by the stimulator to the
brain area to reduce muscle contractions. The human doctor regulates the
frequency and intensity of electrical impulses.
Medications can help
reduce the "overload" messages that cause muscle tension in dystonia.
Medications used include:
- Levodopa
- Procyclidine hydrochloride
- Diazepam
- Lorazepam
- Clonazepam
- Baclofen
The sensory trick is
another option. With a sensory trick, stimulation applied to or near the
affected body part can reduce muscle contractions. By simply touching this
area, people can control their own contractions.
Speech therapy,
physical therapy, and stress management can also be used to treat symptoms of
dystonia.