Chorea is a movement disorder that causes uncontrolled and irregular muscle movements. This happens because of too much dopamine activity in the brain, and there are many possible reasons for this.
Chorea is a kind of dyskinesia, which means it’s part of a group of disorders where the brain’s movement control areas are overstimulated by dopamine.
Chorea can be a sign of different health issues. How it is treated and the outlook for recovery depends on what is causing it. Healthcare providers will adjust the treatment based on the specific cause of the chorea.
Causes
Chorea can arise from various conditions that impact the brain. In adults, abnormalities of genetics are often the cause, with Huntington’s disease being the most commonly linked genetic disorder. In individuals, the most frequent kind is Sydenham chorea.
Several conditions can lead to chorea:
- Huntington’s Disease: This hereditary condition progressively causes dementia and loss of motor control.
- Sydenham Chorea: This type of chorea can occur in children following a cluster A streptococcal infection, which is linked to rheumatic fever. It can persist for many years even after the infection is treated and may sometimes resolve itself.
- Parathyroid Hormone Abnormality: A deficiency in parathyroid hormone can lead to low calcium levels, which may result in focal chorea.
- Medication Side Effects: Certain medications, particularly those used to medicate Parkinson’s disease, can cause chorea as a side effect.
- Thyroid Disease: High levels of thyroid hormones can sometimes impact the brain, leading to chorea.
- Systemic Lupus Erythematosus: This condition can lead to various symptoms, including chorea, though this is rare.
- Paraneoplastic Syndromes: Uncommonly, malignant tumors can create antibodies that trigger the brain.
- Brain Damage: Conditions such as brain tumors, stroke, infections, or injury that damage brain areas responsible for movement can lead to chorea.
- Chorea Gravidarum: This type of chorea occurs during pregnancy and generally reduces after delivery.
Symptoms
People with chorea face uncontrolled movements that make it difficult to maintain steady positions, movements, or postures. These movements are often nonrepetitive, spontaneous, abrupt, and irregularly timed. The severity of the movements can vary widely, from mild exaggerations to a persistent flow of unstable motions.
In addition to the characteristic movements, people with chorea may exhibit other symptoms. One such symptom is the “milkmaid’s grip,” where an individual struggles to coordinate their hand muscles, leading to a squeezing and releasing motion similar to milking. They might also frequently drop objects. Another symptom is a lack of ability to stick out the tongue properly; the tongue may dart in and out of the mouth uncontrollably. Some individuals may have hypotonia, which is low muscle tone.
Chorea can also include specific forms like athetosis and ballism. Athetosis involves slower, writhing, or twisting movements. Ballism is a more severe kind of chorea, characterized by violent, flinging movements of the limbs, often affecting one part of the body but occasionally both sides.
Since chorea is a symptom of various underlying conditions, individuals facing it will also display symptoms related to the primary disorder causing the chorea.
Treatment
Chorea treatment typically involves addressing the basic cause of the condition.
In some situations, such as when chorea is related to pregnancy, symptoms might go away on their own without any treatment. However, in other episodes, adjustments to current treatment might be necessary to manage the symptoms.
For Sydenham chorea, which often improves on its own, treatment may not always be required. However, if the symptoms are severe, healthcare providers might prescribe medications to help control them. These could include sedatives like barbiturates and benzodiazepines or antiepileptic drugs like valproic acid.
Since chorea is linked to abnormal activity in the brain by dopamine, there are specific medications designed to address this. Tetrabenazine is a drug that helps decrease dopamine levels, while antipsychotics work by blocking dopamine receptors.
In some severe cases, deep brain stimulation might be considered. This procedure involves implanting electrodes in the brain to help control abnormal brain impulses. However, the DBS is still considered experimental and is usually only recommended for the most serious cases.
Diagnosis
Diagnosing chorea involves gathering comprehensive information about the individual and their symptoms due to the condition’s various potential causes. Healthcare providers will start by asking detailed questions about the person’s medical history, family history, symptoms they might be experiencing, and how long the symptoms have been present.
To pinpoint the underlying cause of chorea, healthcare providers may order several types of tests. Blood examination can be used to detect any signs of metabolic issues or infection. Imaging tests, such as CT or MRI scans, help find any issues within the brain. Additionally, genetic testing may be conducted to determine if the gene associated with Huntington’s disease is present.
Outlook
The outlook for someone with chorea depends on what is causing it.
If chorea is caused by temporary factors like pregnancy or medication, people often make a full recovery once these issues are resolved.
However, recovery isn’t always guaranteed. For instance, many children with Sydenham chorea, which is linked to rheumatic fever, will eventually get better. Still, about one-third of these children may experience a return of symptoms 18 to 30 months after their first case.
In contrast, chorea related to Huntington’s disease has a more challenging outlook. Many individuals with Huntington’s disease live between 10 to 30 years after being diagnosed.
Summary
Chorea is a movement disorder characterized by irregular, dance-like movements. It can be caused by various conditions, including genetic disorders like Huntington’s disease, infections like Sydenham chorea, and side effects from medications. Treatment often focuses on addressing the basic cause, which may include adjusting medications or using specific drugs to manage dopamine activity. In some cases, like with severe Sydenham chorea or when other treatments fail, deep brain stimulation may be considered. The outlook depends on the cause, with some cases resolving on their own and others requiring ongoing management.
