Athetosis is the set of slow, fluid and contortionary involuntary movements. It usually affects the hands and feet. This palotogy is an uncommon manifestation of certain neurological diseases, especially the anatomical or functional damage of the basal ganglia.
What are the basal ganglia?
The basal ganglia, are structures formed by gray matter and are located in the central portion of the brain. They are characterized by a large number of connections with other structures within the brain. They are formed by the caudate nucleus, putamen and pale globe.
They participate in the execution and maintenance of motor activity, so that anatomical or functional alterations, given by deficit or excess of certain neurotransmitters, manifest themselves in an evident way in the form of abnormal movements.
Basal ganglia disorders
Most disorders of the basal ganglia are related to functional alterations. This is due to a deficit or excess of certain neurotransmitters, which leads to hypo or electrical hyperactivity in said region. This hypo or hyperactivity is evident in the motor activity of the affected person.
There is a lot of Abnormal movements, such as chorea, dystonia, tremors or athetosis. Chorea consists of repetitive, brief and irregular involuntary movements.
The movements are to a certain extent fast and they start in one part of the body, moving to another in a sudden and unexpected way, and often continuously.
Chorea usually affects the face, mouth, trunk and extremities. Hemiballism is a type of chorea that usually involves violent involuntary spastic movements of an arm or leg. The movements are broader and more intense than those of Korea.
Athetosis, like other manifestations such as Korea, It can be caused by a lot of diseases. In addition, its presence guides the diagnosis in a certain way. Chorea and athetosis, which can present simultaneously as choreoathetosis. They are not disorders in themselves, but rather they are symptoms produced by several very different disorders.
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What is athetosis?
Movement disorders can be divided into two types, those corresponding to the hypokinetic and hyperkinetic syndromes, depending on the type of motor activity involved.
Hypokinetic syndromes include Parkinson's disease, neurodegenerative disorders, and secondary parkinsonism. These diseases are characterized by their own symptoms, but due to medications or other organic causes. This includes drugs, infectious diseases, traumas and hydrocephalus.
Hyperkinetic syndromes include a series of obvious physical examination signs that include tremor, chorea, dystonia, tics, and myoclonus. What differentiates athetosis, also called slow chorea, from other disorders is that patients are unable to maintain a part of the body in a certain position. It manifests with slow, constant and unavoidable movements.
It usually occurs in the distal portions of the limbs, tongue and throat, although it can occur anywhere on the body. The slow movements characteristic of this disorder allows to differentiate it from other alterations such as chorea. Although there are similar clinical forms called choreoathetosis.
The term choreoathetosis is applied to different generative diseases such as Huntington's disease, very feared by the inevitable course of the disease.
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Other causes of athetosis
There are other causes of athetosis, such as Central nervous system infections such as encephalitis. They are related to the diffuse and severe damage of the entire brain tissue. For this reason, movement disorders and signs are quite common.
On the other hand, autoimmune disorders such as Systemic lupus erythematosus can also present with this type of neurological alterations, although it is not the most typical presentation of the disease.
However, these patients should receive long-term treatment with immunosuppressants such as steroids. As a consequence, there may be a tendency to nervous system infections. This can trigger movement disorders, something similar to what happens in encephalitis.