- St. Vitus dance
- rheumatic chorea
- chorea minor
Chorea is an abnormal involuntary movement that is quick, purposeless, and that usually involves the arms and/or legs. Sydenham chorea is one of several syndromes in which these abnormal movements are seen. It usually occurs in young children and is caused by an abnormal response by the immune system to a recent streptococcal infection, such as "strep throat".
What is going on in the body?
Sydenham chorea is caused by destruction of brain cells in a part the brain called the basal ganglia. This part of the brain, when damaged, causes movement disorders. The damage in Sydenham chorea results from antibodies that are made by the immune system in response to a streptococcal group A infection. These antibodies mistake the cells of the basal ganglia for the streptococcal bacteria. A similar scenario occurs in rheumatic fever except that in that case the antibodies have confused the heart valves for the bacteria.
What are the causes and risks of the condition?
The cause of Sydenham chorea is abnormal immune system attack on brain cells in the basal ganglia by antibodies made by the body to attack streptococcal bacteria. The main risk is in children who have had throat infection by streptococcal group A bacteria. Streptococcal infections of the skin do not cause Sydenham chorea.
What can be done to prevent the condition?
Most cases of Sydenham chorea can be prevented by early diagnosis and prompt treatment of streptococcal infections with antibiotics.
How is the condition diagnosed?
The first step in diagnosing Sydenham chorea is a complete medical history and physical examination.
Blood tests can verify the presence of antibodies specifically made to attack streptococcal bacteria. Antibodies that specifically target the basal ganglia can also be detected. A throat culture may help to evaluate for acute strep throat.
Long Term Effects
What are the long-term effects of the condition?
Sydenham chorea usually improves on it own within several months; however, up to half of individuals will have some chorea at two years. Sydenham chorea is associated with behavioral abnormalities such as obsessive compulsive disorder. In addition, because Sydenham chorea and rheumatic fever share a common cause, an evaluation for heart valve damage secondary to anti-streptococcal bacteria should be done.
What are the risks to others?
Sydenham chorea itself is not contagious. However, the streptococcal infection that caused the infection is contagious.
What are the treatments for the condition?
Antibiotics are given prophylactically (or routinely, to prevent further streptococcal infection) up to the age of 21. If Sydenham chorea begins for the first time after this age, then antibiotic prophylaxis may be given indefinitely. The symptoms of chorea, if severe, may require antiepileptic medications such as valproic acid or carbemazepine.
What are the side effects of the treatments?
Antiepileptic medications can cause fatigue and drowsiness. Antibiotics can cause stomach upset and allergic reactions.
What happens after treatment for the condition?
Sydenham chorea usually goes away on its own with no long term effects; however, it may recur later, not associated with a new streptococcal infection.
How is the condition monitored?
Any new or worsening symptoms should be reported to the healthcare professional.
Isselbacher KJ, Braunwald E, Wilson, JD, et al: Harrison's principles of internal medicine. ed 13; p 122, 1049-50. New York, 1994, McGraw-Hill