In 265 children and adolescents with rheumatic fever who were followed into and beyond the convalescent period, the average duration of acute inflammatory activity was 109 ±57 days. The average duration was significantly longer in patients who had valvular involvement (124 days) than in those who did not (89 days). In patients who received a relatively short course of anti-inflammatory treatment and who then had a posttherapeutic clinical rebound which was allowed to subside spontaneously, the total duration of rheumatic activity was almost identical to that found in patients whose entire attack had been untreated. These results suggest that the duration of rheumatic activity is prolonged by prolonged therapy but is unaffected when the original course of treatment is shorter than the natural course of the acute inflammation.
Feinstein AR, Spagnuolo M. The Duration of Activity in Acute Rheumatic Fever. JAMA. 1961;175(13):1117-1119. doi:10.1001/jama.1961.03040130001001