Sydenham's chorea

Sydenham's chorea is a movement condition that follows infection with group A streptococcus, the bacteria behind strep throat, and is considered a major feature of rheumatic fever. The leading explanation is molecular mimicry, meaning antibodies made against the strep bacteria are thought to cross-react with the basal ganglia, the brain areas that help coordinate movement. It mostly affects children, with onset most often reported between ages seven and twelve, and is more frequent in girls.

Research describes it as a major manifestation occurring in up to 40 percent of people with rheumatic fever, remaining uncommon in the United States while occurring more frequently in developing countries. The chorea often eases within six months in about half of cases, though it persists longer in others, and mood or attention changes frequently accompany the movement changes.

Common signs

Rapid, irregular, involuntary movements of the face, hands, and feet that ease during sleep, along with clumsiness, a weak or fluctuating grip, slurred speech, emotional ups and downs, and sometimes anxiety or obsessive-compulsive symptoms.

This is a plain-language summary for orientation, not a diagnosis. Mechanisms are described as current understanding, not settled fact. Work with your own clinician for your care.