Dystonias

What are Dystonias?

Dystonia is a term used to describe a range of conditions and disorders that cause irregular muscle contraction and spasms. Dystonia refers to spasms that can either be short-lived or persistent. It can affect a single muscle, a muscle group or the whole body. It is thought that dystonia affects around 1 percent of the population. Although it can affect both females and males, it is more commonly found in females. Although dystonia is categorised as a neurological disorder, it does not usually affect cognitive function.

Dystonia types

Dystonia covers a wide range of disorders and there are various different types. The type is characterised by the area of the body that is affected. There are five major types of dystonia and these include:

Focal dystonia: this relates to dystonia in a single part of the body and it usually makes specific tasks more difficult. For example, if the hands are affected, writing becomes harder. Examples of focal dystonia include cervical dystonia (the neck) and laryngeal dystonia (affecting the larynx or the voice box).
Segmental dystonia: this form of dystonia affects two regions of the body, which are joined. For example, cranial dystonia may occur when the jaw and the tongue are affected.
Multifocial dystonia: this relates to at least two, or often several, different areas, which are not connected. For example, the right arm and the right leg.
Generalised dystonia: this relates to dystonia that affects several parts of the body, including the trunk. Often, the legs are affected, but this is not always the case.
Hemidystonia: this occurs when only one side of the body is affected. In this case, all areas on that side are affected.

The most common types of dystonia are cervical dystonia and blepharospasm (this affects the movement of the eyelids).

What causes dystonia?

It is not fully understood why some people develop dystonia. However, experts believe that the basal ganglia, the part of the brain responsible for movement in the muscles, is involved. In cases where there is no underlying cause, dystonia is defined as primary. When dystonia is associated with other conditions or injuries, such as strokes, trauma, Parkinson’s disease and encephalitis, this is known as secondary dystonia.

Who is affected?

Dystonia affects around 70,000 people in the UK, of which around 7,000 are children. It is slightly more common in women than men.

What are the symptoms?

Symptoms vary according to the part of the body affected and the stage of life at which it develops. In cases where dystonia develops at an early age, symptoms tend to affect the arms and legs before they spread to other parts of the body. In cases that develop later in life, the head is usually affected first.

Dystonia in children

Dystonia in children, also known as early-onset dystonia, may be characterised by the following symptoms:

muscle spasms
abnormal posture and twisting movements
sudden jerky movements
having one arm, leg or foot that points inwards
stiffness in the muscles

Dystonia in adults

Symptoms that may affect adults include:

involuntary muscle movements in the neck (cervical dystonia)
neck pain (cervical dystonia)
stiffness (cervical dystonia)
frequent blinking, struggling to close the eyes and heightened sensitivity to light (blepharospasm)
changes in the sound of your voice (laryngeal dystonia)
difficulty swallowing, grimacing and pouting (oromandibular dystonia)

How is dystonia diagnosed?

Dystonia is usually diagnosed based on symptoms. The type of dystonia is diagnosed based on which area or areas of the body are affected. If dystonia is linked to underlying causes or an injury or accident, this may be treated as a priority. Tests ordered to determine if dystonia is primary or secondary include blood tests, scans of the brain, urine samples and genetic testing.

How is dystonia treated?

Although there is no cure for dystonia, treatments can be used to manage symptoms successfully. Treatment options tend to depend on the type of dystonia and whether or not there is an underlying cause. The main treatment options include:

Botox (botulinum toxin type A): Botox paralyses the muscles by blocking nerve signals to the muscles to prevent them from contracting
Medication to relax the muscles and prevent spasms
Physiotherapy to strengthen the muscles and improve the range of movement
Surgery: this is usually a last resort, but may be recommended if other treatments are ineffective. Surgery may involve cutting the nerves to prevent muscle spasms or implanting an electrode and connecting it to a stimulator similar to a pace-maker

What is the prognosis?

Dystonia affects people in different ways and to different degrees. Sometimes, it progresses slowly and symptoms are mild and other times, symptoms progress quickly and can be much more severe. In some cases, usually with secondary dystonia, symptoms subside completely with effective management.