Dystonia is a condition in which there are repetitive jerking twisting movements, or abnormal postures due to stained muscle contraction.
The muscles muscles contract uncontrollably causing the affected body part to twist involuntarily, resulting in repetitive movements or abnormal postures. It can affect one muscle, a muscle group, or the entire body. the condition affects about 1% of the population, and women are more prone to it than men.
The movements may be painful, and some individuals may have a tremor or other neurological features. There are several different forms of dystonia that may affect only one muscle, groups of muscles, or muscles throughout the body.
Dystonia is often intensified or exacerbated by physical activity, and symptoms may progress into adjacent muscles.
Most commonly it is seen as a focal disorder, e.g. torticollis or writer’s cramp.
Causes of Dystonia
The dystonias can be divided into three groups- idiopathic, genetic, and acquired.
Idiopathic or primary dystonia refers to dystonia that does not have a clear cause.
In most cases cause may not be found. The underlying cause seems to be related to a problem in the basal ganglia, parts of the brain concerned with motor function, such as the basal ganglia, and the GABA (gamma-aminobutyric acid) producing Purkinje neurons.
There are several genetic causes. Symptoms may vary widely in type and severity. Some people with defective gene may not develop dystonia.
Acquired or secondary dystonia, results from environmental or other damage to the brain, the basal ganglia. The main mechanism is inflammation of the blood vessels, causing restriction of blood flow to the basal ganglia. Other mechanisms include direct nerve injury by the organism or a toxin, or autoimmune mechanisms. The damage could be the result of:
- Brain trauma
- Oxygen deprivation
- Infection- Meningitis and encephalitis
- Drug reactions
- Wilson Disease
By the body part they affect-
- Generalized – Affects most of or all of the body.
- Focal – Affects just a specific body part.
- Multifocal- Affects more than one unrelated body part.
- Segmental- Involves adjacent body parts.
- Hemidystonia – Hemidystonia affects the arm and leg on the same side of the body
- Acute Dystonic Reaction
Generalized dystonia are generally genetic and can be seen in various syndromes like Oppenhiem syndrome and Flatau-Sterling syndrome.
The children are born with normal birth history and milestones. The dystonia starts generally in childhood, begins in lower limbs and spreads upwards.
These are also known as torsion dystonia or idiopathic torsion dystonia or dystonia musculorum deformans.
Focal dystonia are the most common . Examples are
- Anismus – affects muscles of the rectum and caused painful defecation, constipation
- Cervical dystonia or spasmodic torticollis affects muscles of the neck and causes the head to rotate to one side, to pull down towards the chest, or back, or a combination of these postures.
- Blepharospasm affects muscles of eyes and causes rapid blinking of the eyes or even their forced closure causing functional blindness.
- Writer’s cramp is a type of dystonia that only occurs while writing. It affects the hand and/or forearm muscles.
Segmental dystonias affect two adjoining parts of the body:
- Hemidystonia affects an arm and foot on one side of the body.
Early-onset dystonia often begins with symptoms in the limbs and may progress to involve other regions.
Adult-onset dystonia usually is located in one or adjacent parts of the body, most often involving the neck and/or facial muscles. Acquired dystonia can affect other regions of the body.
Loss of precision of movement may be the earliest symptom. For example hand involvement may lead to frequent small injuries to the hands, and dropped items. Depending on the area involved, there may be a dragging leg, foot cramping, and involuntary pulling of the neck, uncontrollable blinking and speech difficulties.
It may progress to cramping pain with sustained use, and trembling worsened by exertion.
Initially, dystonic movements may be intermittent and appear only during voluntary movements or stress. Later, may occur without activity or stress. Fixed postures and shortening of tendons may occur in severe cases.
Abnormal posturing, continuous pain, cramping, and relentless muscle spasms may be present
Stress or fatigue may bring on the symptoms or cause them to worsen.
Disturbed sleep patterns, exhaustion, mood swings, mental stress, difficulty concentrating, blurred vision, digestive problems, and short temper are secondary effects.
Depression may occur in these patients.
In some cases, symptoms may progress and then plateau for years, or stop progressing entirely. The progression may be delayed by treatment or adaptive lifestyle changes, .
- Parkinson’s disease
- Essential tremor
- Carpal tunnel syndrome
- Tourette’s syndrome
- conversion disorder
- Other neuromuscular movement disorders
Few Common Dystonias
It is also called spasmodic torticollis or torticollis and is the most common of the focal dystonias. The muscles in the neck that control the position of the head are affected, causing the head to turn to one side or be pulled forward or backward. It can occur at any age, although mostly occurs in middle age. It often begins slowly and has a gradual progression.
It is the second most common focal dystonia, is the involuntary, forcible contraction of the muscles controlling eye blinks. The first symptoms may be increased blinking, and usually both eyes are affected. Spasms may cause the eyelids to close completely, causing “functional blindness” even though the eyes are healthy and vision is normal.
Tt is a term used to describe dystonia that affects the muscles of the head, face, and neck. The term Meige syndrome is sometimes applied to cranio-facial dystonia accompanied by blepharospasm.
Oromandibular dystonia affects the muscles of the jaw, lips, and tongue. This dystonia may cause difficulties with opening and closing the jaw, and speech and swallowing can be affected.
Spasmodic dysphonia, also called laryngeal dystonia, involves the muscles that control the vocal cords.
These tend to occur only when undertaking a particular repetitive activity. Examples include writer’s cramp, typist’s cramp, pianist’s cramp, and musician’s cramp.
DYT1 dystonia is caused by a mutation in the DYT1 gene. It is autosomal dominant. This form of dystonia typically begins in childhood, affects the limbs first, and progresses, often causing significant disability.
Dopa-responsive dystonia or Segawa’s disease, is a childhood onset and have progressive difficulty with walking. Symptoms characteristically fluctuate and are worse late in the day and after exercise. Patients improve dramatically with levodopa.
There are no medications to prevent dystonia or slow its progression. There are, however, several treatment options available.
Reduction of the types of movements that trigger or worsen dystonic symptoms provides some relief. Reduction of stress also helps.
Botulinum injections often into affected muscles prevents muscle contractions and can provide temporary improvement in the abnormal postures and movements that characterize dystonia.
These block the effects of the neurotransmitter acetylcholine. Drugs in this group include trihexyphenidyl and benztropine. Sedation,dry mouth and constipation may occur.
These regulate the neurotransmitter GABA and include benzodiazepines [diazepam, lorazepam, clonazepam and baclofen. Drowsiness may occur
These act on the dopamine system and the neurotransmitter dopamine, which helps control muscle movement. Some individuals may benefit from drugs that block the effects of dopamine, such as tetrabenazine.
Dopa-responsive dystonia is a specific form that most commonly affects children, and often can be well managed with levodopa.
Deep brain stimulation
It may be recommended when medications are not effective or side effects are severe. The procedure involves surgically implanting small electrodes that are connected to a pulse generator into specific brain regions that control movement. Controlled amounts of electricity are sent into the exact region.
Surgeries aim to interrupt the pathways responsible for the abnormal movements. It may be surgery that cause damage to small regions of the thalamus or other deep centers in the brain.
Anterior cervical rhizotomy or selective peripheral denervation is also found effective.
- Speech therapy
- Voice therapy
- Use of splints
- Stress management
- Occupational Therapy