There is usually loss of fine motor control, particularly obvious in handwriting if the child is of school age. Speech is often affected (dysarthria), as is walking; legs will suddenly give way or flick out to one side, giving an irregular gait and the appearance of skipping or dancing. Underlying the abnormal movements is often low tone (hypotonia) which may not become obvious until treatment is started to suppress the chorea. In severe cases, the loss of tone and weakness predominate (chorea paralyticum). The severity of the condition can vary from just some instability on walking and difficulty with hand writing, to the extreme of being wholly unable to walk, talk, or eat. Movements cease during sleep. The eye muscles are not affected, curiously.It is a neuropsychiatric disorder, so besides the motor problems there is classically emotional lability (mood swings, or inappropriate mood), anxiety, attention deficit. These can precede the motor symptoms.Non-neurologic manifestations of acute rheumatic fever may be present, namely carditis (up to 70% of cases, often subclinical, so echocardiography required), arthritis, erythema marginatum, and subcutaneous nodules. Differentiating these signs from other involuntary movements such as tics and stereotypies can be difficult, and since these things are not uncommon they can potentially co-exist. Diagnosis is often delayed and attributed to another condition such as tic disorder or conversion disorder. The controversial PANDAS (pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections) hypothesis has overlapping clinical features but Sydenhams chorea is one of the exclusion criteria.
Case reports exist to support carbamazepine and levetiracetam; other drugs tried include pimozide, clonidine, and phenobarbitone. Immunosuppression
Immunosuppression is used inconsistently in Sydenhams chorea. The model of an autoimmune disorder would support its use. One randomized controlled trial of steroids from Paz, Brazil in 2006 (22 cases) showed remission reduced to 54 days from 119 days. Various other reports of use of oral or IV steroids from Israel, Italy and Brazil . Immunoglobulin has been used in Holland and South Africa. Some improvement can be seen within a few days of IV steroids. In Italy, prednisolone reduced average duration of symptoms from 9 weeks to 4 weeks, and these were severe cases. South African group found less neuropsychiatric complications at 6 months with IVIG treatment (IVIG preferred due to fear of TB reactivation).A course of penicillin is usually given at diagnosis to definitively clear any remaining streptococci, but there is no evidence that this is an effective treatment. Active infection is usually cleared by diagnosis. Penicillin prophylaxis, on the other hand, is essential to treat cardiac features of rheumatic fever, even if subclinical (American Heart Association guideline). If the case is of isolated chorea, it is arguable whether cardiac risk justifies prophylaxis or not, however it is likely to reduce recurrence. There are several historical case series reporting successful treatment of Sydenhams chorea by inducing fever. Prognosis
Motor problems including chorea settle within an average of 2–3 months. Recurrence seen in 16–40% of cases. Recurrence is more likely with poor compliance with penicillin prophylaxis.