Lay summary
Sydenham’s chorea is a disabling disorder of uncontrollable movements and psychiatric symptoms which is seen in 6-28% of children with rheumatic fever. Sydenham’s chorea is caused by an abnormal immune response to Group A streptococcus infection, and remains endemic in Māori, Pasifika, Aboriginal, and Torres Strait Islander children. There is limited evidence to direct treatment of Sydenham’s chorea, and clinical practice differs widely within New Zealand and Australia. Dexamethasone is an oral steroid which targets the abnormal immune response and successfully treats other immune brain disorders, without adverse effects. TREAT-SC is a multi-site, randomised, double-blinded, placebo-controlled trial which will investigate whether a three-day course of dexamethasone safely and effectively treats the movement disorder and psychiatric symptoms of Sydenham’s chorea. Oral dexamethasone has the potential to demonstrably reduce the under-recognised neurodisability associated with Sydenham’s chorea in New Zealand and Australia.