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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 14-year-old boy is brought to the physician because of fever, malaise, and severe right knee joint pain and swelling for 3 days. He had also had episodes of abdominal pain and epistaxis during this period. Five days ago, he had swelling and pain in his left ankle joint which has since resolved. He reports having a sore throat 3 weeks ago while he was camping in the woods, for which he received symptomatic treatment. His immunizations are up-to-date. His temperature is 38.7°C (101.6°F), pulse is 119/min, and blood pressure is 90/60 mm Hg. Examination shows a swollen, tender right knee; range of motion is limited. There are painless 3- to 4-mm nodules over the elbow. Cardiopulmonary examination is normal. His hemoglobin concentration is 12.3 g/dL, leukocyte count is 11,800/mm3, and erythrocyte sedimentation rate is 58 mm/h. Arthrocentesis of the right knee joint yields clear, straw-colored fluid; no organisms are identified on Gram stain. Analysis of the synovial fluid shows a leukocyte count of 1,350/mm3 with 17% neutrophils. Which of the following is the most likely diagnosis?
assistant
Acute rheumatic fever