A 17-year-old girl presents with a four-day-history of fever, malaise, and migratory joint pain involving the right knee, right ankle, right elbow, and left knee successively. The affected joints were tender and swollen, but not erythematous. There was no morning stiffness. Close questioning reveals a sore throat about two weeks ago, from which she recovered completely. She has otherwise been healthy, with all her vaccinations up-to-date. She is not on any medications, has no known allergies, and denies recreational drug use. She is currently single but has been sexually active earlier, with her last episode of intercourse around a month ago. Her family history is unremarkable.
WBC: 12,000/mm3 (4,600 -11,000) N: 80% L:15% Hb: 13.2 g/dL (11.0-18.0) Hct (PCV): 38% Plt: 209,000/mm3 (150,000-400,000) CRP: 96 mg/L (<1mg/L)
ASOT: 500 IU/mL (<400)
Culture reports will be available in 48 to 72 hours.
The ECG is only significant for a PR interval of 0.24 sec (normal: 0.12-0.20 sec). Echocardiography shows thickening of the mitral and aortic valve leaflets and moderate mitral insufficiency. There are no other valvular or structural lesions, and the ejection fraction is >70%.