Recurrence of Sydenham chorea: implications for pathogenesis.

BACKGROUND: Sydenham chorea (SC), a major sign of rheumatic fever (RF), is related to systemic streptococcal infection and is treated with antibiotics. Recurrence usually occurs within a short interval following the initial event and is considered part of RF.

OBJECTIVE: To evaluate the rate, nature, and course of recurrent SC during an extended follow-up period.

DESIGN: Prospective assessment of a cohort of patients with SC who were admitted between 1985 and 2002.

SETTING: General community hospital.

METHODS: Diagnosis of RF was based on the revised Jones criteria. Other causes of chorea were excluded. Recurrence was defined as the development of new signs, lasting more than 24 hours and separated by a minimum of 2 months from the previous episode. Patients were observed from 1 to 14 years following the initial SC episode and for at least 1 year after recurrence. At recurrence, patients were assessed for RF clinical and laboratory activity, including change in cardiac involvement.

RESULTS: Twenty-four patients had SC. In 19 patients (79%), the chorea was associated with other RF signs, and 5 suffered from pure chorea. Ten patients (42%, 7 women) developed 11 recurrent episodes of chorea 3 months to 10 years after the initial episode. Association of recurrent chorea with RF could be suspected in only 6 episodes: cessation of prophylactic antibiotic treatment or poor compliance in 4 patients and rise in antistreptolysin O titers in 2. In an 18-year-old woman, chorea recurred during her first pregnancy. At recurrence, chorea was the sole rheumatic sign in all 9 patients who had 1 recurrent episode. In the patient with 2 recurrent episodes, mitral regurgitation developed into mitral stenosis. No statistical differences in previous RF activity and rheumatic cardiac involvement between patients with recurrent SC and patients with a single episode could be found.

CONCLUSIONS: In a significant subgroup of patients, SC recurrence might not be a true relapse of rheumatic fever. It might represent either a primary underlying abnormality that renders patients susceptible to developing such a movement disorder or the outcome of permanent subclinical damage to the basal ganglia following the initial SC episode.