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".
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.
Symptoms of Sydenham chorea appear gradually after 1 to 2 months following a streptococcal throat infection. Usually the chorea starts in one side of the body in an arm and/or leg with subtle abnormal, purposeless, and quick muscle contractions that then worsen and spread to the other side.
Difficulty speaking clearly is common and is related to the actual pronunciation of speech rather than a problem with language. In severe cases, the individual becomes bedridden because of the uncontrollable movements.
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.
Most cases of Sydenham chorea can be prevented by early diagnosis and prompt treatment of streptococcal infections with antibiotics.
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.
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.
Sydenham chorea itself is not contagious. However, the streptococcal infection that caused the infection is contagious.
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.
Antiepileptic medications can cause fatigue and drowsiness. Antibiotics can cause stomach upset and allergic reactions.
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.
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