Rheumatic fever in a high incidence population: the importance of monoarthritis and low grade fever.

AIMS To describe the clinical features of rheumatic fever and to assess the Jones criteria in a population and setting similar to that in many developing countries. METHODS The charts of 555 cases of confirmed acute rheumatic fever in 367 patients (97% Aboriginal) and more than 200 possible rheumatic fever cases from the tropical "Top End" of Australia's Northern Territory were reviewed retrospectively. RESULTS Most clinical features were similar to classic descriptions. However, monoarthritis occurred in 17% of confirmed non-chorea cases and 35% of unconfirmed cases, including up to 27 in whom the diagnosis was missed because monoarthritis is not a major manifestation. Only 71% and 25% of confirmed non-chorea cases would have had fever using cut off values of 38 degrees C and 39 degrees C, respectively. In 17% of confirmed non-chorea cases, anti-DNase B titres were raised but antistreptolysin O titres were normal. Although features of recurrences tended to correlate with initial episodes, there were numerous exceptions. CONCLUSIONS Monoarthritis and low grade fever are important manifestations of rheumatic fever in this population. Streptococcal serology results may support a possible role for pyoderma in rheumatic fever pathogenesis. When recurrences of rheumatic fever are common, the absence of carditis at the first episode does not reliably predict the absence of carditis with recurrences.