The ataxia is A symptom that is described as the loss of muscular control of the extremities, which causes problems when moving and walking. This lack of motor control occurs because the individual's nervous system is damaged.
The causes of ataxia vary widely, from trauma to neurodegenerative disease. Depending on the specific cause and symptoms, several types of ataxia may be differentiated.
It is necessary that the type of ataxia is correctly identified and diagnosed, since there are specific treatments for each type of ataxia.
Characteristics of ataxia
Ataxia is a symptom of loss of muscle control for voluntary movements, such as walking or catching objects. There is a lack of coordination and a general imbalance. They may also be affected by language (due to problems of articulation), eye movements and Swallowing .
When ataxia persists over time, it is usually because there is damage in nervous system , Usually in the cerebellum .
This damage can be caused by multiple causes, including drugs abuse , A tumor, a neurodegenerative disease such as multiple sclerosis Or even a genetically inherited condition.
There are treatments to help improve the functionality of people with ataxia. The specific treatment to be used depends on the cause of the ataxia, but usually includes physical therapy, occupational therapy, language and some external aids such as dogs.
symptom
Ataxia itself is a symptom composed of several signs including:
- Little motor coordination.
- Problems walking.
- Continuous stumbling.
- Difficulty performing any motor task, such as eating, writing or dressing.
- Problems to articulate the words.
- Nystagmus (rapid and involuntary eye movements).
- Difficulty to swallow…
These signs can appear both progressively and suddenly, usually after a trauma.
Causes
Ataxia occurs because there is degeneration or loss of nerve connections. These can be located in the inner ear (the cochlea ), at peripheral nervous system Or, more commonly, in the cerebellum.
When ataxia is caused by damage to the cerebellum Is called cerebellar ataxia . The cerebellum has two parts or hemispheres that control the contralateral part of the body, so that if there is an injury in the left hemisphere The deficit in the movements of the right part of the body and the opposite with the right hemisphere will be observed.
Injuries to the cerebellum can occur due to multiple causes such as:
Cranioencephalic injury
A strong blow to the head produced, for example, in a car accident can damage the brain or spinal cord And cause a type of ataxia called acute cerebellar ataxia, because it starts suddenly.
A cerebral infarction
A cerebral stroke Consists of the interruption of blood flow of a part of the brain, so that nutrients and oxygen do not arrive and the cells of that area can deteriorate or be destroyed, depending on how long the infarct lasts.
Transient ischemic attack
Transient ischemic attack involves the temporary decrease of blood flow in a brain area. This decrease usually lasts only a few minutes and the ataxic signs can be observed with temporal.
Cerebral palsy
The cerebral palsy Is a condition that can be seen in multiple disorders and is caused by brain damage caused in the early stages of development, usually when the child is less than 2 years old. Among the symptoms produced by this condition is ataxia.
Multiple sclerosis
The multiple sclerosis Is a neurodegenerative disease that is caused by the deterioration of the Myelin (The material that envelops the axons so that the nerve connections are produced correctly), the causes of this deterioration are unknown.
People with this disease have multiple symptoms, both physical and cognitive, and one of them is ataxia.
Varicella and other viral infections
Ataxia may occur, rarely, as a result of chickenpox and other viral infections. It usually appears at the end of the illness, when it is already healing, and usually lasts only a few days.
Paraneoplastic syndromes
This term encompasses a set of neurodegenerative disorders that occur as a result of the attack of the immune system to a specific type of cancer called neoplasm.
The most common neoplasms are ovarian, lung, breast or lymphatic. Ataxia may appear months or years after the cancer is diagnosed.
Brain tumors
Both malignant (cancer) and benign, can damage the cerebellum And cause ataxia.
Side effects of some medications
Some medications may produce a toxic reaction that includes ataxia among its symptoms. Among the drugs most at risk of producing this side effect are the Barbiturates , Like the Phenobarbital , And sedatives such as Benzodiazepines .
Poisoning
Some substances such as drugs, heavy metals, solvents... can cause poisoning that have ataxia among its symptoms. The duration of this symptom depends on the severity of the poisoning.
Deficiency of vitamin E or vitamin B-12
The deficiency of these nutrients can cause cerebral damages that end up causing ataxia.
Others
In some cases, no specific cause is found for why ataxia has occurred, in which case ataxia is called degenerative sporadic ataxia, which may be a symptom of multisystem atrophy or progressive or degenerative disorder.
Types of ataxias
Cerebellar ataxia is classified according to its cause. As has been shown there are many causes, but generally speaking, only two categories are different: hereditary and genetic. Although some classifications also include idiopathic ataxia and unknown causes.
Hereditary ataxias
This category includes all ataxias whose cause is hereditary, that is, the condition that causes it has been inherited by the parents and, therefore, is present from birth, although it does not have to be observed any symptoms until adulthood .
These ataxies occur because there are one or several genes that do not work well and do not create proteins correctly. If the proteins are not in good condition they can cause problems in the cells, in this case in the nervous system. Nerve cells degenerate over time, so these ataxias are usually progressive and the symptoms are getting worse.
Hereditary diseases can be of two types, autosomal dominant if only one parent is required to present the disease or autosomal recessive, if it is necessary to inherit the gene from both parents to manifest the disease.
In the second case it is possible that the parents do not know that they are carriers of the gene since they do not present any symptoms of the disease.
Depending on the gene that is affected and the type of affection ataxia will have specific characteristics, although in all can be observed a poor motor coordination.
- Dominant autosomal ataxias
Included in this category are:
- Spinocerebellar ataxias . Currently 20 genes have been found that are involved in the onset of this symptom and the list continues to increase. Specific signs depend on the affected gene, as well as the age of onset, although in all of them cerebellar degeneration is present.
- Episodic ataxias (AE) . Within this group are included ataxias that occur sporadically and usually last a few minutes. This type of ataxia does not usually shorten the life expectancy of patients and the signs are usually controlled fairly well with the medication. Currently there are seven types of episodic ataxias recognized, they are called as AE and a number behind according to the order of their discovery (from 1 to 7). The most common are EA1 and EA2.
- In AI1 the ataxic episodes are mild and usually last only a few seconds or minutes. Ataxic"crises"can be elicited by stressful, surprising or abrupt or sudden movements, and often accompanied by muscular spasms.
- EA2 is characterized by presenting longer episodes, which can last between 30 minutes and 6 hours, in which the person can feel vertigo, fatigue and muscular weakness. This type of ataxia may originate for the same reasons as AI1.
- Recessive autosomal ataxias
Included in this category are:
- Ataxia of This : Is the most common hereditary ataxia. Symptoms are caused by damage to the cerebellum, spinal cord, and peripheral nerves. Symptoms usually begin to appear before age 25.
The first clue is usually difficulty walking, but gradually the symptoms spread to the trunk and upper limbs.
As time goes by the muscles deteriorate and deformities occur, especially in the feet, legs and hands.
When the disease is very advanced, other symptoms such as Dysarthria (Difficulty speaking), fatigue, nystagmus, scoliosis (deformity of the spine), hearing loss and heart disease, such as cardiomyopathy (heart enlargement), which can lead to heart failure.
Hereditary ataxias
- Ataxia-telangiectasia
This type of ataxia is quite rare, begins in childhood and is progressive so it is degenerating brain And other organs. This disease is usually accompanied by some immunological disease, so that the immune system can fail to fight against other infectious diseases.
The most characteristic sign of this disease are the telangiectasias, or"spiders", that are veins that are seen in the eyes, the ears and the cheeks, although there are people in whom they do not appear. The first symptoms to appear are motor retardation, poor balance and difficulties to articulate well.
Children also often suffer from infections in the respiratory tract. Patients with ataxia-telangiectasia are more likely to get some types of cancer, such as leukemia or lymphomas. The life expectancy of patients suffering from this disease, usually die in adolescence or early adulthood (around 20 years).
- Congenital cerebellar ataxia
This type of ataxia occurs as a result of an injury to the cerebellum produced before or during birth.
Wilson's disease
The Wilson's disease Is characterized by the accumulation of copper in some organs such as the brain and liver. The accumulation of copper in the brain damages them and causes problems such as ataxia.
Diagnosis
Once the person has been shown to show the typical signs of an ataxia, professionals will look for the cause of the condition by performing physical and neurological tests, including both clinical and neuroimaging tests.
During clinical neurological tests, professionals will assess their cognitive status (including memory and attention), their vision, hearing, balance, coordination, and reflexes.
The neuroimaging studies that are usually performed are the Computed tomography wave magnetic resonance . In these tests you can see the structural state of our brain and determine if the ataxia is due to a lesion in the cerebellum.
Sometimes a lumbar puncture can also be performed, in which a needle is inserted into the spinal cord to extract cerebrospinal fluid for later analysis and check for any problems.
Finally, if there is suspicion that the ataxia is hereditary, a genetic analysis is also done to check if there is any genetic mutation that may be causing the disease.
Treatment for ataxia
There is no single treatment for ataxia, since the treatment focuses on curing the cause that has caused ataxia (eg, chickenpox). In addition, therapies are also often Improve Life Quality from the patients.
The treatment usually includes physical therapies to strengthen muscles and improve mobility, occupational therapies to improve the quality of life of the person by teaching him to perform the tasks of daily living efficiently and language therapy if the person has difficulty speaking And articulate words.
Some support tools such as dogs or walkers may also be needed, utensils modified to make it easier to write or eat, and tools to facilitate communication, especially oral.
References
- Mayo Foundation for Medical Education and Research. (March 29, 2014). Ataxia .
- National Ataxia Foundation. (S.f.). Ataxia Classification.
- NIH. (2016 February 2016). NINDS Ataxias and Cerebellar or Spinocerebellar Degeneration Information Page . Retrieved from National Institute of Neurological Disorders and Stroke