Dystonia refers to a range of movement disorders characterized by muscle spasms and contractions. The contractions may be sustained or intermittent and are often awkward and sometimes painful. In some forms of the condition, the patient may also experience tremor.
Dystonia is thought to be neurological in origin, but the condition does not affect people’s intelligence, memory or language ability. If the dystonia is genetic or the cause is unknown, it is termed primary dystonia, while dystonia that occurs due to an underlying disease such as stroke, encephalitis, Parkinson’s disease or head injury, is referred to as secondary dystonia.
There are several types of dystonia, with some forms of the condition affecting only one muscle or a group of muscles and other forms of the disease affecting the body more generally. Dystonia can be divided into five main forms, which include:
Focal dystonia affects only a single region such as the hand or an eye. Examples include twitching of the eyelid (blepharospasm), writer’s cramp, laryngeal dystonia, and cervical dystonia (involving the neck muscles). Cervical dystonias and blepharospasm form nearly 90% of all dystonia cases.
This form of dystonia involves two or more unconnected regions of the body, such as the left arm and the right arm.
This type involves two or more parts of the body that are connected such as the lower face, jaw and tongue.
Here, the trunk of the body is affected along with at least two other parts of the body.
Hemidystonia refers to when one whole half of the body is affected.
Diagnosis and treatment
Diagnosis involves a detailed neurological and physical examination. First, the symptoms and features of the dystonia are established in order to determine which form of dystonia a person has. Establishing whether the dystonia is primary or secondary is also important. Examples of the tests that may be involved in diagnosing dystonia include blood and urine tests, brain scans and genetic testing.
There is no cure for dystonia but certain medications can help ease symptoms and make the condition easier to live with. One of the main treatments is administration of the botulinum toxin, which can reduce the muscle spasms. Other medications that can ease spasms include anticholinergics and muscle relaxants such as Baclofen. Physiotherapy may be used to improve the patient’s range of movement and posturing as well as to strengthen the muscles. If other treatments are not effective, surgery may be performed to cut the nerves that cause the spasms.
Reviewed by Sally Robertson, BSc