What is Chorea?

The World Federation of Neurology’s Committee on Classification defines chorea as a condition where a person experiences excess, sudden movements that aren’t repetitive and have no specific timing or distribution. They’re sudden and can differ in how severe they are. They can range from restlessness and exaggerated gestures to uncontrolled movements that disrupt daily functioning, resembling a dance. This is why the term ‘chorea’, which is similar to ‘choreography’, is used.

Chorea is often accompanied by athetosis and ballism. Athetosis is a slower version of chorea, marked by twisting or writhing movements. On the other hand, ballism is an extremely severe form of chorea, with violent, uncontrollable limb movements that can be compared to flinging. Usually, these movements affect one side of the body, but in rare cases, they can occur on both sides.

What Causes Chorea?

Chorea is a type of movement disorder, often associated with Huntington’s disease, that can cause uncontrollable, irregular movements. There are many diseases besides Huntington’s that can result in chorea, like spinocerebellar ataxia subtypes, Wilson’s disease, Sydenham chorea, and conditions affecting the basal ganglia – a part of the brain involved in the control of voluntary movement.

When we look at brain scans of patients with chorea, we often see shrinkage of a brain part called the caudate nucleus. Huntington’s disease, a genetic condition causing chorea, is due to a mutation in the gene known as HTT, located on chromosome 4.

However, chorea can also be triggered by many other factors:

* It can be caused by endocrine and metabolic conditions, such as low blood sugar, overactive thyroid, kernicterus (a severe form of jaundice), and low magnesium levels.
* Infectious diseases like rheumatic fever, syphilis, a brain inflammation called subacute sclerosing panencephalitis, Lyme disease, toxoplasmosis, HIV, and heart infection (endocarditis) can also result in chorea.
* Certain medications like levodopa (used in Parkinson’s disease treatment), birth control pills, antipsychotics, antihistamines, cocaine, amphetamine, and antidepressants (tricyclics) can induce chorea.
* Toxins such as carbon monoxide, mercury, and alcohol can also lead to chorea.
* Neurologic conditions, like stroke and migraine.
* Vascular conditions, such as polycythemia, Churg Strauss syndrome, systemic lupus erythematosus (SLE), Behcet’s syndrome, and multiple sclerosis, may cause chorea.
* Lastly, both primary brain tumors and metastatic lesions (spread of cancer from other parts of the body to the brain) can cause chorea.

Risk Factors and Frequency for Chorea

Chorea is a condition that can happen in a variety of different disorders. While the incidence, or occurrence, of chorea in specific disorders is known, we don’t have complete data for its global incidence. Below are some disorders in which chorea is common:

  • In Huntington disease, a neurodegenerative disorder that’s typically inherited, there are about 5-10 cases per 100,000 people in the US, mainly seen in Caucasians. However, it’s also appearing in people who have migrated and settled in South and Central America.
  • Wilson disease impacts multiple systems in the body and is inherited. It has a prevalence of about 30 cases per million people.
  • Benign hereditary chorea is a rare disorder that’s also inherited. It occurs in approximately 1 out of every 500,000 people.

Chorea can happen at any age. For younger people, the most common triggers are infections, physical injuries, and inflammatory conditions.

For a specific type called Huntington chorea, most people start showing signs in their 40s or 50s, and the condition worsens over time. It’s unusual for this condition to appear before someone turns 30. If it does occur early, it’s usually because the affected person got the gene from their father. If the onset is late, it’s likely that the gene came from the mother.

Signs and Symptoms of Chorea

Chorea is a health condition where patients experience uncontrolled movements, making it hard for them to maintain a steady posture or hold a position. One sign of this can be seen when a patient tries to grip an object, they will involuntarily release and squeeze it repeatedly. They also often drop objects.

The condition can affect both close-to-body (proximal) and farther-from-body (distal) muscles. While most patients have normal muscle strength, some may have weaker muscle tone, also known as hypotonia.

The most common reason people seek medical help for this condition is because of excessive unintended movements of parts of the body. These irregular “choreiform” movements can be easily seen. Other signs can include problems with controlling the tongue’s movement, where a patient can’t keep their tongue stuck out and it moves in and out of the mouth. An MRI scan can show the typical signs of chorea, such as shrinking of the caudate area of the brain, shown by the widening of the brain’s lateral ventricles. Further into the disease, patients may show changes in their thinking and behavior.

Testing for Chorea

If a doctor suspects someone has Huntington’s disease, they may use various methods to confirm their diagnosis. One method might be genetic testing, as Huntington’s is a hereditary condition. Other examinations could include brain imaging scans, such as computed tomography (CT) or magnetic resonance imaging (MRI), which help doctors see any changes or damage in the brain.

In addition, a psychiatrist might look for issues in a patient’s cognitive, behavioral, and functional areas, as Huntington’s can also affect these aspects. It is also crucial to ask about suicidal thoughts, as they can be prevalent among people with Huntington’s disease.

Sometimes, a positron emission tomography (PET) scan is used. This scan can help doctors evaluate conditions such as Huntington’s chorea and neuroacanthocytosis. These conditions often show decreased activity in certain parts of the brain like the putamen and caudate nucleus. However, this decrease in activity won’t always appear in individuals with benign hereditary chorea – a milder, non-progressive form of the disease.

Treatment Options for Chorea

While there’s currently no cure for this disease, the symptoms can be managed and quality of life can be improved. One key aspect is developing a strong support system for the patient because as the disease progresses, they will need expert caregiving. Proper nutrition is also critical because swallowing can become difficult. Tetrabenazine is a medication that’s been approved to manage the symptom of involuntary, jerky movements called chorea.

In terms of medical treatment, most patients receive drugs called neuroleptics, which stop certain chemicals in the brain like dopamine from working. Other medications, including valproate, clonazepam, and gabapentin, that affect another brain chemical called GABA, are also used. Two potential treatments showing promise in animal studies are minocycline, an antibiotic, and CoQ10, a natural antioxidant. They may help with chorea, but in some cases, chorea related to heart transplants responds to steroids, and for other patients with chorea caused by rheumatic fever, a blood-cleansing procedure called plasmapheresis may shorten the course of the symptom. However, it’s important to note that while these treatments can reduce chorea in some patients, they also carry strong side effects.

Surgery is another option but is used less commonly. Over the recent decade, a surgery called deep brain stimulation (DBS) has been explored and might be useful in some patients. DBS is performed by placing electrodes in a specific part of the brain. While there are reports that DBS works and eases chorea in some patients, it’s still experimental, doesn’t work for everyone, and can lead to complications.

Another experimental surgical treatment is neural cell transplantation, which has been trialled in a small number of patients with Huntington’s chorea, a type of involuntary movement disorder. But again, not all patients have seen improvement with this approach.

  • Huntington’s disease
  • Lesch-Nyhan syndrome
  • Lyme disease
  • Multiple system atrophy
  • Neuroacanthocytosis
  • Surgery for torticollis in children
  • Ramsay Hunt syndrome
  • Striatonigral degeneration
  • Tourette’s syndrome
  • Viral encephalitis

These are various health conditions or procedures that doctors might consider when diagnosing and treating neurological disorders.

What to expect with Chorea

The outlook for people with chorea, a condition causing irregular, spontaneous movements, largely depends on its root cause. Many individuals with Huntington’s chorea face a grim prognosis and usually have a shortened lifespan. Those with neuroacanthocytosis, another cause of chorea, are similarly affected.

Severe involuntary movements can lead to localized injuries or a serious condition called rhabdomyolysis, where damaged muscle tissue breaks down rapidly.

In some cases, patients with neuroacanthocytosis or those with tongue dystonia, a condition that causes involuntary muscle contractions, may experience problems with swallowing. This can lead to weight loss and recurring bouts of aspiration pneumonia, a lung infection caused by inhaling food, stomach acid or saliva into the lungs. In extreme cases, these complications can even result in death.

Frequently asked questions

Chorea is a condition characterized by excess, sudden movements that are not repetitive and have no specific timing or distribution. These movements can range from restlessness and exaggerated gestures to uncontrolled movements that disrupt daily functioning, resembling a dance.

The incidence of chorea in specific disorders is known, but there is no complete data for its global incidence.

Signs and symptoms of Chorea include: - Uncontrolled movements, making it difficult to maintain a steady posture or hold a position. - Involuntary release and squeezing of objects when trying to grip them. - Dropping objects frequently. - Irregular "choreiform" movements of different body parts, which are easily visible. - Problems with controlling the movement of the tongue, where it moves in and out of the mouth instead of being stuck out. - Weaker muscle tone (hypotonia) in some patients. - Changes in thinking and behavior as the disease progresses. - Typical signs of chorea can be seen on an MRI scan, such as shrinking of the caudate area of the brain and widening of the brain's lateral ventricles.

Chorea can be caused by various factors such as genetic conditions like Huntington's disease, endocrine and metabolic conditions, infectious diseases, certain medications, toxins, neurologic conditions, vascular conditions, and brain tumors or metastatic lesions.

The doctor needs to rule out the following conditions when diagnosing Chorea: - Huntington's disease - Lesch-Nyhan syndrome - Lyme disease - Multiple system atrophy - Neuroacanthocytosis - Ramsay Hunt syndrome - Striatonigral degeneration - Tourette's syndrome - Viral encephalitis

The types of tests that may be needed for Chorea include: - Genetic testing to confirm the diagnosis, as Chorea can be hereditary. - Brain imaging scans such as CT or MRI to detect any changes or damage in the brain. - Positron emission tomography (PET) scan to evaluate conditions like Huntington's chorea and neuroacanthocytosis, which often show decreased activity in certain parts of the brain. - Cognitive, behavioral, and functional examinations by a psychiatrist to assess the impact of Chorea on these aspects. - In some cases, additional tests like deep brain stimulation (DBS) or neural cell transplantation may be considered, although these are experimental and not commonly used.

Chorea can be treated through a combination of medication and surgical options. Medications such as neuroleptics, valproate, clonazepam, and gabapentin are commonly used to manage the symptoms of chorea. Tetrabenazine is a specific medication approved to manage the involuntary, jerky movements associated with chorea. In some cases, minocycline and CoQ10 have shown promise in animal studies. Surgical options include deep brain stimulation (DBS) and neural cell transplantation, although these are less commonly used and still considered experimental. It's important to note that while these treatments can reduce chorea in some patients, they may also have strong side effects and may not work for everyone.

The side effects when treating Chorea can include the following: - Strong side effects from medications such as neuroleptics, valproate, clonazepam, and gabapentin. - Potential side effects from minocycline and CoQ10, which are being studied as potential treatments. - Complications from deep brain stimulation (DBS) surgery, which is still experimental and doesn't work for everyone. - Not all patients have seen improvement with neural cell transplantation, another experimental surgical treatment.

The prognosis for Chorea largely depends on its root cause. Individuals with Huntington's chorea typically have a grim prognosis and a shortened lifespan. Those with neuroacanthocytosis, another cause of chorea, are similarly affected. Severe involuntary movements can lead to localized injuries or a serious condition called rhabdomyolysis, where damaged muscle tissue breaks down rapidly. In some cases, patients with neuroacanthocytosis or tongue dystonia may experience problems with swallowing, leading to weight loss and recurring bouts of aspiration pneumonia, which can even result in death in extreme cases.

A neurologist.

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