What is Athetoid Cerebral Palsy?
Athetoid cerebral palsy, often referred to as dyskinetic cerebral palsy, is a form of cerebral palsy (CP). Cerebral palsy is a collection of stable disorders that limit physical activity due to issues that develop during motor control development. These disturbances, which occur during the unborn baby’s development or in the infant’s brain, do not worsen over time. As a group, cerebral palsy is the most frequent cause of disability in children.
Dyskinetic cerebral palsy is the second most prevalent form of cerebral palsy. It affects approximately 12% to 14% of individuals with the condition, with the spastic form being the most common. Athetoid cerebral palsy is characterized by abnormal postures and movements due to problems with muscle tone, control of movement, and coordination. These irregularities can be categorized by describing the typical movements, like those associated with dystonia, extrapyramidal symptoms, choreoathetosis, choreoathetoid, or athetoid cerebral palsy.
What Causes Athetoid Cerebral Palsy?
Spastic cerebral palsy (CP) is usually linked with premature birth or long-lasting mid-level loss of oxygen, leading to damage in the brain’s white matter. On the other hand, dyskinetic CP (DCP), a different type of cerebral palsy, relates to injuries in different parts of the brain, namely the basal ganglia and thalamus. These injuries tend to occur due to brief but severe instances where the body doesn’t get enough oxygen. Interestingly, DCP is more often seen in infants than spastic CP.
Another reason for DCP can be neonatal hyperbilirubinemia-induced kernicterus, a condition where a yellowish substance collects in the brain. Fortunately, with measures to prevent high bilirubin levels in babies, kernicterus and hence DCP cases have decreased. Besides, any damage to the basal ganglia and thalamus – such as from bleeding in the brain, stroke, or brain infection – can also lead to DCP.
Risk Factors and Frequency for Athetoid Cerebral Palsy
Cerebral palsy is a leading cause of disability in children, occurring in about 1.5 to 2.5 out of 1000 newborns. The most frequently seen type is spastic cerebral palsy which includes specific subtypes: spastic diplegia, spastic hemiplegia, and spastic quadriplegia.
- Dyskinetic or athetoid cerebral palsy, which is the focus of this article, accounts for about 12% to 14% of all cerebral palsy cases. This translates to about 1.8 to 3.5 cases per 10,000 newborns.
- The least prevalent subtype of cerebral palsy is the ataxic kind, constituting 4% to 13% of all cerebral palsy cases.
- It’s noteworthy that dyskinetic cerebral palsy is more common in term infants, whereas spastic cerebral palsy is more frequently associated with preterm birth.
Signs and Symptoms of Athetoid Cerebral Palsy
Dyskinetic cerebral palsy is a type of cerebral palsy that is identified based on a patient’s medical history and clinical symptoms. Certain risk factors, such as lack of oxygen during birth or severe jaundice in the neonatal period, can be indicative of this condition. Additionally, family history might be useful in ruling out other neurological or movement disorders. Patients with dyskinetic cerebral palsy often experience motor and other developmental delays, so a developmental history is also crucial.
It’s important to also inquire about other health issues that may go along with dyskinetic cerebral palsy. Compared to the spastic type, non-motor-related health issues may be more common with this variant. These can include severe intellectual impairment, problems with speech, and epilepsy. Other common issues may include weight loss, poor feeding, sleep disturbances, respiratory problems, and musculoskeletal deformities.
The physical exam aids in determining whether the patient has dyskinetic cerebral palsy versus other types of cerebral palsy. The type of muscle abnormalities and their locations help characterize the specific subtype. Some common signs of dyskinetic cerebral palsy can include:
- Delayed motor development and decreased spontaneous movements in early infancy
- Involuntary movements and unusual body posturing starting from age 2 to 3
- Type of involuntary movements, such as sudden, irregular muscle contractions (chorea), or slow, writhing movements (athetosis). These can worsen with emotions, stress, or illness.
In dyskinetic cerebral palsy, repetitive, patterned movements called dystonia may also be observed. These can involve twisting of the limbs and trunk, and may be slow or fast. These movements can increase with physical movement or emotional stress.
Testing for Athetoid Cerebral Palsy
Apart from your medical history and physical examination, brain imagery also plays a key role in assessing athetoid cerebral palsy. Brain scans like magnetic resonance imaging (MRI) can show issues in parts of the brain called the basal ganglia or thalamus. These issues are found in about 70% of patients with dyskinetic cerebral palsy. A few patients may show normal scan results. For patients who had kernicterus (a rare type of brain damage), the MRI commonly shows irregularities in an area of the brain known as the globus pallidus.
Special clinical scales and tools are used to determine the severity of complex conditions associated with athetoid cerebral palsy such as dystonia (involuntary muscle contractions) and choreoathetosis (uncontrollable movements). These tools include the Barry-Albright Dystonia Rating scale, the Burke-Fahn-Marsden Dystonia Rating scale, and the Dyskinesia Impairment scale. They help doctors understand how severe the dystonia is in patients with dyskinetic cerebral palsy. These scales, though helpful, have certain limitations as they can’t assess choreoathetosis.
To overcome this, doctors use the Dyskinesia Impairment Scale which specifically helps measure this condition in patients with dyskinetic cerebral palsy. Both this scale and the Burke-Fahn-Marsden Dystonia Rating scale are widely used to measure treatment outcomes, like deep brain stimulation.
Treatment Options for Athetoid Cerebral Palsy
Treating dyskinetic cerebral palsy (CP) is aimed at alleviating symptoms and enhancing the patient’s quality of life. That involves dealing with movement disorders characterised by involuntary, erratic movements (known as dystonia and choreoathetosis), as well as related pain, disability, and discomfort. It’s also important to address non-motion-related conditions, such as epilepsy and depression. Other considerations include the patient’s nutrition, potential muscle contractures, and bone-related complications.
Patients with dyskinetic CP need a collaborative approach that brings together various health professionals, including doctors, therapists, and behavioral health specialists. The main focus for intervention is to reduce disability and allow the patient to have the best quality of life possible.
Medications are part of the treatment, but many are not very effective. One commonly used drug is baclofen, taken orally, which interacts with a certain type of brain receptor. Trihexyphenidyl is commonly used for controlling dystonia. However, their effectiveness in treating dyskinetic CP is quite limited. There might also be repercussions, as reducing dystonia can sometimes accentuate choreoathetosis, a condition where involuntary, random movements are present. This can happen because dystonia often hides the presence of choreoathetosis.
Medications can be used to manage movement problems, which may include:
For dystonia, drugs that enhance the activity of brain chemicals (levodopa, trihexyphenidyl, benztropine, diazepam, clonazepam, baclofen, tetrabenazine, and carbamazepine) can be used, whereas benzodiazepine receptor agonists (diazepam, clonazepam), dopamine antagonists (pimozide, haloperidol), and calcium channel blockers (levetiracetam) can be used for choreoathetosis.
As an alternative to oral medication, which often has limited efficacy and more side effects, intrathecal baclofen (administered into the spinal fluid) can sometimes be used. This can be given in smaller doses and usually has fewer side effects. Some studies suggest that it can help reduce dystonia.
Deep brain stimulation (DBS), a surgical treatment that involves implanting a device to send electrical signals to brain areas responsible for body movement, is used increasingly in patients with dyskinetic CP, to decrease dystonia. However, it seems to have less impact on overall quality of life and functionality in CP patients, compared to those with inherited dystonia.
Botulinum toxin, commonly known by one of its brand names, Botox, is also often used as a treatment for dystonia in dyskinetic CP. It seems to help reduce pain and dystonia, but, once again, its effects appear to be more beneficial in those with primary dystonia.
What else can Athetoid Cerebral Palsy be?
When trying to figure out a medical diagnosis for certain symptoms, doctors may need to consider several different possibilities. These can include conditions related to movement, nerve-muscle interactions, degenerative brain conditions, and genetic metabolic disorders. They often have to rule out other disorders that may cause abnormal, uncontrolled, often painful muscle contractions known as dystonia, or irregular, jerky body movements known as chorea.
The list of conditions they might need to consider includes:
- Glutaric aciduria type 1: a disorder that can damage the brain and cause movement problems
- Lesch-Nyhan syndrome: a condition that causes overproduction of uric acid, leading to various physical and mental problems
- Niemann-Pick disease: a group of severe metabolic disorders affecting brain function and physical abilities
- Pelizaeus-Merzhacher disease: a genetic disorder affecting the nervous system, leading to movement, coordination, and cognitive issues
- Rett syndrome: a rare genetic disorder causing severe physical and mental disability that almost exclusively affects girls
- Leigh’s disease: a severe neurological disorder that typically becomes apparent in the first year of life
- Pyruvate dehydrogenase deficiency: a rare genetic disorder that can affect nervous system function and lead to neurological problems
- Dopamine-responsive dystonia: a condition affecting movement and muscle tone, often improving with medications
- Primary dystonia: a group of disorders characterized by sustained or intermittent muscle contractions causing abnormal movements and postures
What to expect with Athetoid Cerebral Palsy
The lifespan of people with cerebral palsy varies depending on how severe their disability is and any additional complications they may have. Generally, those with a higher degree of disability will have a shorter lifespan compared to those with a lesser degree of disability.
Particularly, people with a type of cerebral palsy called ‘dyskinetic cerebral palsy’ often face earlier death compared to those with other types of cerebral palsy. This is because they experience more complications and a higher level of disability. Regardless of the type of cerebral palsy, the most common cause of death is usually complications with breathing, due to conditions like pneumonia and inhalation of foreign substances.
In dyskinetic cerebral palsy, physical impairment tends to be more severe than in other forms of the condition. People with this condition usually score higher on tools that measure their motor skills and manual abilities, indicating a higher level of disability. The level of disability tends to increase with the severity of dyskinesia, a type of movement disorder, more so than with choreoathetosis, another type of movement disorder.
Possible Complications When Diagnosed with Athetoid Cerebral Palsy
Cerebral palsy can come with many complications. These include intellectual disability, problems with speaking and hearing, certain bone and joint disorders, behavioral disorders, and difficulty sleeping. Persons with a specific type of cerebral palsy known as dyskinetic cerebral palsy often go through more severe complications due to the condition’s harsh effects on motor function.
One common issue is being underweight. Even though many people with this type of cerebral palsy have normal birth weights, they often weigh less than average as they grow older. This is thought to be because their involuntary movements require a lot of energy and combined with problems eating and swallowing, leaves them nutritionally deficient. Moreover, these patients generally cannot live independently because their condition is severe and they have other diseases at a higher rate than the average population.
Additionally, non-motor complications could also be a problem. These can include:
- Severe intellectual impairment,
- Language disabilities,
- Epilepsy,
- Visual and hearing problems,
- Pain,
- Musculoskeletal deformities.
- Mental health issues, especially depression.
In the severe cases, the most common cause of death in patients with dyskinetic cerebral palsy is complications related to breathing, which include aspiration (breathing in food, liquids, or vomit into your lungs) and pneumonia, eventually leading to respiratory failure.
Preventing Athetoid Cerebral Palsy
Dyskinetic cerebral palsy is a specific type of cerebral palsy that happens due to an injury to the brain during the later stages of pregnancy or during birth. This condition is characterized by abnormal body posture, muscle tension, and involuntary movements. The chances of having this kind of cerebral palsy are higher if there was a brain injury, a lack of oxygen during birth, or a condition called kernicterus, which is associated with high levels of a substance called bilirubin.
Out of all the different types of cerebral palsy, dyskinetic cerebral palsy is the second most common, following spastic cerebral palsy. In general, cerebral palsy is the most common cause of disability in children. Doctors diagnose dyskinetic CP by examining the child’s medical history, performing a physical exam, and by using brain imaging techniques.
The goal of treating and managing dyskinetic cerebral palsy is to improve the child’s ability to move and perform everyday activities, and overall increase their quality of life. This can be best accomplished with the help of a diverse team of professionals coming together to focus on the child’s wellbeing.