What is chorea?
Chorea is derived from the word for “dance” and refers to an ongoing random-appearing sequence of one or more discrete, involuntary movements. The movements appear random due to variability in frequency, duration, rate, direction and the body part(s) affected. All body parts may be involved.
Sydenham's chorea
Sydenham's chorea (SC) is one of the most common forms of acquired chorea in children. Unlike many movement disorders people are born with, it is caused by infection, so it is acquired. SC is caused by group A beta-hemolytic streptococcal infection. It is part of the spectrum of disorders associated with rheumatic fever. Other diseases or medications can cause other forms of chorea.
Girls are more affected than boys. Most patients are between five and 15 years old.
Signs and symptoms of Sydenham's chorea
With all movement disorders, abnormal signals from the brain cause patients to have trouble controlling the muscles of their bodies.
Children with SC usually have rapid, involuntary, uncoordinated jerking movements. The movement most often affects the face, hands and feet but can also affect the whole body. Sometimes, the movements affect only one side of the body. Children with SC may also have muscle weakness.
The movements can occur at rest or while active. Movements may increase with drowsiness or distracting activities, such as counting or performing mental arithmetic.
Symptoms usually do not appear during sleep.
Short term
The movements can interfere with daily activities such as eating, handwriting and dressing. Because the movements are relatively mild, children often try to hide them. They may incorporate an involuntary movement into one that appears to have a purpose. For example, an involuntary head movement may be turned into a flick of the hair. Sometimes, children will sit on their hands to try to stop the movements.
Children may seem clumsy and may drop or spill things frequently. Sometimes children have repetitive "piano playing" type movements or they may be unable to hold things in their hands. SC may also cause bursts of uncontrolled speech.
Longer term
Some children with SC will have a symptom months or years after the disorder has gone away the first time. Usually, this happens about two years after the first signs of SC have cleared.
As they grow into adulthood, girls may have recurring symptoms if they take birth control pills or estrogen, or if they get pregnant.
Behaviour, feelings and Sydenham's chorea
Sometimes, children with SC develop behavioural and emotional symptoms. These might include depression, anxiety, personality changes, being overly emotional, obsessive-compulsive disorder (OCD), tics and attention deficit/hyperactivity disorder (ADHD).
It is not known if these behavioural changes are part of SC or a result of SC. Sometimes emotional outbursts happen just before involuntary movements begin.
If your child with SC is attending school, you may want to inform the school about your child's condition, including the possible emotional and behavioural symptoms.
What causes Sydenham's chorea?
SC is believed to be an autoimmune disorder. In an autoimmune disorder, the immune system fights against itself and mistakenly reacts against healthy tissue. In Sydenham's chorea, the body creates antibodies against a streptococcal infection. Then, these antibodies persist and start targeting other organs, such as the heart, kidneys and brain.
SC is one of the major diagnostic criteria of rheumatic fever.
Course of Sydenham's chorea
SC usually does not last. Most cases disappear on their own between three to six months after first appearing. In some children, the movement can last up to two years. Sometimes, the movements will go away and then return.
Diagnosing Sydenham's chorea
Diagnosis of SC can be difficult initially. There are many different types of movement disorders, many of which have different causes. Often at the beginning, their symptoms appear the same.
Even though SC is caused by a streptococcal infection, the infection may be gone from the body by the time movement symptoms begin.
A patient and family history is taken when diagnosing SC. This is because the doctors will want to find out if the child or other members of the family have had a current or recent infection, as well as to distinguish from other types of hereditary chorea.
In most cases, the diagnosis will be made based on the child’s signs, symptoms and medical history in combination with a blood test for streptococcal antibodies. After the diagnosis is confirmed, all children will require cardiac evaluation.
Treatment of Sydenham's chorea
The movements of Sydenham's chorea are often not treated because the symptoms are so mild and the condition will most likely go away on its own after a few months. More severe cases, where the movements interfere with function, may be treated with medications. These medications may include:
- Anticonvulsants (like
valproic acid and
carbamazepine), which can reduce the frequency and severity of movements. Low doses of dopamine receptor blockers, such as haloperidol, or dopamine depletors, such as tetrabenazine, are also used. Since most children improve over time, they are usually not at risk of the long-term complications observed with these drugs. However, you should always discuss the potential benefits and risks of medications with your health-care provider.
- Steroids may be used in severe and resistant cases. They help to get rid of antibodies that may cause symptoms to worsen.
The doctor will also assess your child's heart. This is done because chorea is associated with rheumatic fever. Patients who have Sydenham's chorea may have an affected heart.
Children with SC will require treatment for streptococcal infection. They will then need prophylactic antibiotics to prevent further streptococcal infections. The duration of prophylaxis depends on if there are changes to the heart.
Potential complications of Sydenham's chorea
When a child is diagnosed with SC, they should be evaluated for inflammation of the heart (carditis).
Children with SC will require long-term antibiotic treatment. This helps prevent permanent heart valve damage, which could result if the child experiences recurrent streptococcal infections. Continuing long-term antibiotic treatment also helps to prevent recurrent episodes of SC.
Resources
National Organization for Rare Disorders. Sydenham Chorea. Retrieved from https://rarediseases.org/rare-diseases/sydenham-chorea/
National Institute of Neurological Disorders and Stroke. Sydenham Chorea Information Page. Retrieved from: https://www.ninds.nih.gov/Disorders/All-Disorders/Sydenham-Chorea-Information-Page