Dystonia is a condition in which the muscles begin to contract involuntarily. This causes uncontrollable and repetitive movements that result in abnormal postures in the affected body part. The condition may affect just a single muscle or it could affect a muscle group or the entire body. The symptoms may vary in severity and can be painful at times and there may also be other symptoms like tremors and other neurologic features. Dystonia symptoms can range from mildly debilitating to severe, interfering with one’s ability to perform even mundane everyday tasks.
Although dystonia can affect almost anyone it is more common in women and affects around 1% of the population. Treatment can help to control the symptoms and restore quality of life but the condition itself is not curable.
Types of Dystonia
Dystonia can be broadly categorized into five distinct types based on the muscle or group of muscles affected. Dystonia’s are further sub-divided or classified according to their symptoms and causes as different syndromes as well. The five types of dystonia include:
- Focal Dystonia – In focal dystonia the condition affects a specific region such as the hand or eyes. Cervical dystonia, which is the most common kind of dystonia, falls into this category. It is not restricted to any particular age group but is generally more prevalent among middle aged individuals. The condition affects the muscles of the neck, causing involuntary movements of the neck, with the head twisting from side to side or being pulled back and forth. Blepharospasm is another focal dystonia that affects the eyelids causing uncontrollable twitching or blinking. Although your vision remains unaffected, the condition doesn’t just cause uncontrollable blinking, but it can cause the eyelid to remain shut for periods of time. What’s worse is that the condition, although it begins with just one eye, progresses to affect both eyelids. Writer’s cramp may not sound as foreboding as the others, but it can be just as bothersome, especially if you earn your livelihood writing. The symptoms affect the hand and forearm muscles, but they only surface while writing.
- Segmental Dystonia – Segmented dystonia is characterized by the appearance of dystonia symptoms in two or more regions of the body that are connected. Cranial dystonia is one such example of segmental dystonia. In cranial dystonia, the muscles that are affected could include those of the head, face and neck. Symptoms of both Blepharospasm and Cervical dystonia would therefore surface. Oromandibular dystonia and spasmodic dystonia are other examples.
- Multifocal Dystonia – In this type of dystonia, again two or more regions are affected with symptoms, but the regions aren’t connected as in the case of segmental dystonia. In such cases, dystonia may affect a leg and an arm or a leg and the neck and so on.
- Generalised Dystonia – This is a less common form of dystonia that affects almost the entire body. Torsion dystonia is one such example and is an early onset dystonia. The condition typically starts in one of the limbs and gradually progresses to affect the trunk and other limbs over a period of five years.
- Hemidystonia – In this type of dystonia the muscle contractions and symptoms only affect one entire side of the body. Most cases of hemidystonia involve cervical dystonia and blepharospasm.
Causes of Dystonia
When examining the causes of dystonia it again becomes necessary to classify the condition into two categories. Primary Dystonia
is believed to be caused due to damage to the basal ganglia, which is a part of the brain. The basal ganglia are a cluster of brain cells that are responsible for muscle control and response. In this context, the term primary simply refers to cases of dystonia in which it is the only neurological disorder
that is present. Primary dystonias include genetic forms, most of which are inherited. In some forms of dystonia, the cause remains unidentified. Focal dystonias often fall into this category.Secondary Dystonia
includes dystonias that are caused by external factors and in which there is a specific underlying cause. Some of these causes include:
- Parkinson’s disease – This is a condition in which there is progressive damage to part of the brain and a drop in dopamine levels.
- Wilson’s disease – This is a genetic disorder in which there is a buildup of copper in the tissues, causing neurological among other symptoms.
- Huntington’s disease – This is an inherited condition in which there is progressive deterioration and damage to certain nerve cells in the brain possibly caused by low levels of brain cholesterol.
- Multiple sclerosis – This is a nervous system disorder and the patient suffers damage and deterioration of the nerves in the central nervous system including the brain.
- Cerebral palsy – This is a neurological condition that usually develops soon after or just before birth and it affects the functioning of the brain and nervous system.
- Brain tumors – This is a condition that can affect people of any age group and involves the growth of a benign or malignant tumor in the brain. The resultant pressure may cause damage or affect the functioning of the brain.
- Stroke – This is a condition in which the flow of blood to a part of the brain is cut off and this can result in irreversible damage to the brain.
- Injury and trauma – Any violent trauma to the skull or spine may cause damage to the nerves and brain itself, resulting in dystonia.
- Infections – Dystonia may in some cases develop because of other diseases like HIV or encephalitis.
- Poisoning – Lead poisoning and carbon monoxide poisoning can both cause dystonia.
- Oxygen deprivation – Loss of oxygen supply to the brain, no matter the cause, can result in severe damage and death of brain cells.
- Side effect of medication – In certain cases dystonia may occur as a reaction to certain medications such as those used to treat epilepsy. Tardive dystonia is in fact the term for dystonia caused by dopamine receptor blocking drugs, commonly used to treat psychiatric or gastrointestinal conditions.
Symptoms of Dystonia
Dystonia symptoms can vary greatly because of the different muscles that may be affected in different regions of the body. Moreover, the symptoms progress as the disease progresses and symptoms can vary from mild to severe.
You will most likely notice the following symptoms:
- Involuntary and uncontrollable contractions of the muscles that result in repetitive or abnormal movements and postures.
- These involuntary contractions may at first be restricted to a specific area, but could spread to other areas in time.
- The symptoms may surface during specific actions such as while writing.
- Stress and anxiety tend to aggravate the symptoms.
- The severity of the symptoms seems to increase with the passage of time.
Dystonia causes symptoms that are specific depending on the region affected:
- Eyelids – Blepharospasm is the type of dystonia that affects the eyes causing involuntary blinking and shutting of the eyelids that could leave you functionally blind when both eyelids remain shut.
- Neck – Cervical dystonia causes involuntary contractions of the muscles in the neck making the head turn from side to side or back and forth and can be painful.
- Face, head and neck – Cranofacial dystonia affects any or all of the muscles in the neck and head region, including the eyes, jaws and neck. In other words it could involve a combination of blepharospasm, cervical dystonia and Oromandibular dystonia, which affects jaw movement. In addition to symptoms of blepharospasm and cervical dystonia it can also cause speech impairment because of involuntary tongue and jaw movement. The patient may also experience difficulty chewing food and swallowing.
- Vocal cords – Spasmodic dysphonia causes uncontrollable contractions of the muscles controlling the vocal cords impairing speech ability.
- Hand and forearm – Writer’s cramp and musician’s dystonia affect the muscles of the hand and forearm only when engaged in a repetitive activity, such as while writing, sketching, playing a guitar or when engaged in certain other tasks.
Diagnosis of Dystonia
To arrive at an accurate diagnosis your doctor will need your help as you need to provide detailed information on the symptoms you experience, your medical history, family history of dystonia if any, past injuries you may have suffered if they involved head trauma or any past or ongoing exposure to certain toxins or drugs.
Your health care provider will need to identify the type of dystonia based on the information you provide and will also consider factors such as –
- Your age at the time of the onset of symptoms
- The sequence or progression of symptom development
- The speed at which the symptoms has progressed
- The results from tests and observation
Some of the tests that may be used to confirm the diagnosis or identify the underlying cause include:
- Blood or urine tests as these can reveal the presence of any toxins that may be responsible.
- Computerized tomography or CT scan to obtain a detailed view of the brain in 3D.
- Magnetic resonance imaging or MRI to give an even more detailed view of the brain if there is a possibility of a brain tumor, lesions or stroke being responsible for the dystonia symptoms.
- Electromyography or EMG, which is used to measure electrical impulses within the muscles.
Treatment for Dystonia
Treating dystonia can be rather complex as it usually consists of a combination of therapies. In addition to such treatment however, complimentary therapies and recuperative therapies are also helpful. For treatment to be effective, the treatment plan should address all aspects of the patient’s wellbeing not just physical treatment with medications and surgery. The emotional wellbeing of the patient is just as important and this is where counseling and support groups come in to play.
Although there are no medications that cure the condition or slow its progression, treatment can provide relief from some of the symptoms. Treatment plans are therefore formulated based on the specific case being dealt with.Botulinum toxin –
Botulinum or botox injections
are quite effective in the treatment of focal dystonias. The chemical is injected into the affected muscle to relax it and prevent muscle contractions. This offers temporary respite from the symptoms. The toxin works by blocking the release of acetylcholine, a neurotransmitter that causes muscle contraction. The injections take effect after a couple of days and will only wear off after several months. At this point the treatment needs to be repeated.Oral Medications –
There are number of medications belonging to different drug classes that are approved by the FDA for the treatment of other conditions. Although they are not specifically approved for dystonia treatment they can help as they affect different neurotransmitters. Responsiveness to treatment can vary greatly among different individuals and will also depend on other factors. Such medications could include:
- Anticholinergic agents are used to block the effect of acetylcholine. At higher dosages these drugs may cause side effects that include difficulty with memory and sedation. These symptoms are especially pronounced in older individuals. This restricts the usefulness of the medication. Other side effects like constipation and dry mouth can be easily addressed without need for further medication.
- GABAergic agents belong to a class of drugs used to regulate GABA, which is a neurotransmitter. These drugs are known to cause drowsiness as a side effect.
Deep Brain Stimulation
- Dopaminergic agents include drugs that act on dopamine to regulate or block the effects of this neurotransmitter. These drugs are known to cause side effects like weight gain and involuntary muscle movement, greatly limiting their use.
It is usually used in the treatment of patients when medications are not adequate in providing relief from symptoms or because of extreme side effects from medications. This is a surgical procedure in which small electrodes are implanted to generate electrical impulses via a pulse generator to regions of the brain that control movement. This is used to send controlled amounts of electricity to precisely that part of the brain responsible for the generation of dystonic symptoms, thereby disrupting and blocking the signals that normally cause the symptoms. Surgery –
In some cases surgeries may be performed to disrupt the pathways that are responsible for generating signals that cause the dystonia. There are different types of surgeries used depending on the particular situation and what would work best for the patient. Some methods involve intentional and very precise damage to small regions of the thalamus, globus pallidus or other parts of the brain. Others involve severing or even removal of nerves at certain points. Many of these measures are found to be extremely effective, with patients reporting significant improvement in symptoms following the procedure.Physical therapy
– Physical therapy and allied disciplines are often used in addition to therapeutic treatment. This helps with rehabilitation and in addition physiotherapy could also include the use of splints and stress management techniques
When dealing with spasmodic dysphonia, speech or voice therapy can also be very helpful.
Complication and Risks of Dystonia
Dystonia presents a definite risk of complications and it does affect quality of life, but the extent to which it affects life will depend on the type of dystonia and its severity. Some of the risks include:
- Physical deformity, which is permanent.
- Restricted mobility and disabilities that can severely restrict your ability to even perform everyday tasks.
- Although vision may be unimpaired, functional blindness can be debilitating.
- Problems with speech, eating and swallowing.
- Mild to severe pain and exhaustion because of the uncontrolled and near constant contraction of the affected muscles.
- Symptoms of dystonia can cause great frustration, stress and depression.