Athetosis refers to the slow, involuntary, and writhing movements of the limbs, face, neck, tongue, and other muscle groups. The fingers are also affected, with their flexing happening separately and irregularly. The hands move, and the toes and feet may also experience the effect.
Another definition of athetosis describes it as slow, continuous, and writhing worm-like movements of the hands, legs, and trunk. The literal meaning of the word is “without position or place”.
The condition is a dysfunction associated with movement, where motion may make it hard to maintain a stable posture. Athetosis may happen continuously and only gets worse when you try to control movement. For example, if you’re typing on a computer and are affected by the condition, it may be hard to control where your fingers land. You might also find it difficult to determine how long your fingers remain on the keyboard.
What Causes Athetosis?
The most common cause of athetosis is an injury to the basal ganglia, which is the part of the brain responsible for motor control. It also influences executive functions, emotions, behaviors, and motor learning. In children, the injury commonly happens during or sometime after birth and is a cause of many forms of cerebral palsy.
Athetosis may happen in adults who have a stroke or severe peripheral neuropathy.
Basal ganglia diseases. Disease or damage in the basal ganglia part of your brain can create symptoms of athetosis. Your brain loses its ability to smooth out muscle movements or coordinate changes in posture. When nerve impulses lack proper control, they lead to uncoordinated muscle movements, abnormal posture, and abnormal increase in tone. Some diseases that affect this part of the brain include Huntington’s disease and Wilson’s disease. Huntington's is hereditary and makes the brain's nerve cells break down over time. Wilson’s disease is a rare genetic disorder that leads to copper poisoning in the body.
Birth problems. If a baby doesn’t get enough air supply during birth, they are at a higher risk of developing athetosis. Lack of oxygen causes brain damage and increases dopamine levels in the brain, affecting the basal ganglia.
Jaundice. If your baby is born with high levels of bilirubin, they can get basal ganglia damage. Treatment helps to lower the amount of the compound. However, the blood-brain barrier that protects the body from toxins doesn’t develop properly. The bilirubin may still find its way to the brain and cause damage.
Drug toxicity. Drugs that increase dopamine levels in the brain can cause damage to the basal ganglia. This will lead to symptoms of athetosis.
Cerebral palsy. Cerebral palsy, or CP, occurs due to abnormal development of or damage to the brain. The result is that a child is unable to control muscle movements. CP that occurs due to damage to the basal ganglia is known as athetoid cerebral palsy. It can also be because of high bilirubin levels and asphyxia or oxygen deficiency from abnormal breathing.
Stroke. Involuntary movements may also arise from stroke, especially in adults. Damage to the brain causes a problem with neuron movement. The results are symptoms of athetosis and other disorders associated with movements.
Symptoms of Athetosis
The signs and symptoms of athetosis depend on the extent of damage and the location of movement issues. The symptoms develop from problems with high and low muscle tone, which can change constantly. High muscle tone can result in jerky movements and stiffness. On the other hand, low muscle tone leads to muscle floppiness and creates trouble in postures like sitting up.
The most common symptoms that come with athetosis are:
- Slow, writhing, and involuntary muscle movements
- Tremors
- Poor sitting or standing posture
- Unsteadiness
- Abrupt movements and changes in muscle movements
- Twisting of the torso
- Grimacing
- Symptoms that get worse with attempts at improved posture or controlled movement
How to Diagnose and Treat Athetosis
Athetosis usually results from overactivity in the basal ganglia. In most cases, excessive dopamine prevents this part of the brain from functioning as it should. Diagnosis depends on symptoms and observation by a doctor. Athetosis is usually a symptom of an underlying disorder and not a disorder by itself.
For proper diagnosis, the doctor will:
- Collect your complete medical history
- Conduct a physical exam
- Carry out blood tests
- Have you undergo brain imaging tests
- Conduct gross motor function tests
Each of these approaches will help determine the severity of the symptoms and rule out the possible causes. It may take time to reach a diagnosis as there are no definite tests for all the possible causes of the condition.
Treatment involves dealing with the underlying cause of athetosis. Treating the cause of irregular muscle movements may reduce or eliminate the symptoms. Sometimes, treatments may include:
- Occupational therapy to help the muscles regain some control
- Anti-dopamine medicine to suppress dopamine effects on the brain
- Botox injections to temporarily limit involuntary movements
