sections include: spasms and cramps, dsytonia
What dystonia, spasms, and cramps have in common are unwanted, involuntary, excessive muscle contractions. These symptoms may be manifestations of a larger problem, especially if they are persistent and widespread, or they may occur on their own.
Spasms and Cramps
The term spasms is perhaps the least specific of the three. Spasms are typically brief contractions that can appear in any muscle in the body, with or without pain. They can be due to many causes, including a reaction to pain, such as when a muscle contracts to avoid pain. This is common when a person has a pinched nerve that causes pain when he or she moves; by contracting, the muscle prevents movement and thus prevents the pain. An example would be a painful herniated disk, which results in involuntary contraction of a back muscle to guard against the pain.
Spasms can be the result of irritated nerves; a common example is facial spasms when a blood vessel is pressing against a facial nerve. This condition has been given the name hemifacial spasm. A change in a person’s blood electrolytes, particularly a reduction of calcium, can produce muscle spasms. Because the term spasm is rather general, people sometimes apply it to various twitches, tics, and other jerks they might encounter, although neurologists prefer to label these other muscle contractions by their distinctive names.
Muscle cramps are painful spasms. The most common occur in the middle of the night, waking a person from sleep. They usually involve the foot or big toe, and the pain is due to excessive shortening of a muscle. These are relaxed by stretching the muscle. Some of these foot cramps are due to decreased sodium in the blood, often from sweating in hot weather without taking in enough salt to make up for the loss. Intestinal cramps are also common. These result when the muscles of the intestines contract excessively.
Dystonia is a neurological disorder in which a person experiences sustained muscle contractions, usually causing twisting movements and even abnormal posture. The involuntary movements can be slow or fast; when fast, they can resemble repetitive muscles spasms.
Dystonia can affect any of the voluntary muscles of the body. Most commonly the condition is confined to a specific body part, producing what is called focal dystonia. Focal dystonias are so common that many have been given their own names, including:
- torticollis (wry neck, or cervical dystonia)
- blepharospasm (blinking and closure of the eyelids)
- dysphonia (dystonia of the vocal cords)
- writer’s cramp and musician’s cramp (dystonia of the hand and arm)
- oromandibular dystonia (sustained jaw clenching or jaw opening)
But dystonia can also spread from one site to adjacent areas, or even the whole body (generalized dystonia). It is usually not painful, except when the neck muscles are involved.
Dystonia is due to a variety of diseases involving the central nervous system, particularly the deep nuclei in the brain. When this condition appears without a known cause or is due to a genetic abnormality, it is called primary dystonia. Several genetic types have been identified. Primary dystonias are not associated with loss of nerve cells—in other words, they are not degenerative disorders. They are more likely due to abnormal physiology in the person’s nerve cells.
Secondary dystonias are the result of an injury to the brain, such as from trauma, encephalitis, strokes (ischemic, hemorrhagic), birth injuries and various toxins and drugs. Some degenerative diseases of the brain can cause dystonia when they damage neurons in the deep nuclei. These include Huntington’s disease, Parkinson’s disease, Hallervorden-Spatz syndrome, and Wilson’s disease.
A neurologist must determine the cause of a patient’s dystonia. The presence of other neurological features on examination would suggest a secondary or degenerative dystonia, because primary dystonia is not associated with other neurological features besides the presence of dystonia and sometimes tremor. Gene testing for one of the primary dystonias is available. For many of the secondary dystonias, the diagnosis can be made on the basis of a detailed history of an insult to the brain or exposure to drugs or toxins. Imaging of the brain, such as a magnetic resonance imaging (MRI) scan, is very helpful. The MRI scan is often abnormal in secondary dystonia and in dystonia due to various neurodegenerative disorders, whereas it is normal in primary dystonia.
Treatment varies, depending on what is appropriate for the condition, and may consist of oral medications, injections of medications into the contracting muscles to weaken them, or surgery involving the deep nuclei in the brain. When a person’s dystonia is severe and disabling and medications have failed to provide sufficient relief, doctors may employ a new technique: implanting electrodes that stimulate the deep nuclei artificially (hence the name deep brain stimulation). This treatment provides relief by neuronal depolarization—that is, blocking conduction of the signals causing the muscle contraction.
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