pediatrics
Rheumatic Fever
Diagnosis of Rheumatic Fever
Modified Jones criteria (for initial diagnosis) Testing for GAS (culture, rapid strep test, or antistreptolysin O and anti-DNase B titers) ECG Echocardiography with Doppler Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) level Diagnosis of a first episode of acute rheumatic fever (ARF) is based on the modified Jones criteria ( Diagnosis reference ; see Table: The modified Jones criteria were designed for the evaluation of acute rheumatic fever rather than for a possible recurrence. However, if patients have a reliable past history of acute rheumatic fever or rheumatic heart disease and also have documented group A streptococcal infection, the criteria may be used to establish the presence of a recurrence. Apreceding streptococcal infectionis suggested by a recent history of pharyngitis and is confirmed by one or more of the following: Positive throat culture Increased or preferably rising antistreptolysin O titer Positive rapid GAS antigen test in a child with clinical manifestations suggestive of streptococcal pharyngitis Recent Scarlet fever is highly suggestive. Throat cultures and rapid strep antigen tests are often negative by the time ARF manifests, whereas titers of antistreptolysin O and anti-DNase B typically peak 3 to 6 weeks after GAS pharyngitis. About 80% of children with ARF have a significantly elevated antistreptolysin O titer; if an anti-DNase B antibody level is also done, the percentage with confirmed GAS infection is higher, especially if acute and convalescent samples are tested. Joint aspirationmay be needed to exclude other causes of arthritis (eg, infection). The joint fluid is usually cloudy and yellow, with an elevated white blood cell (WBC) count composed primarily of neutrophils; culture is negative. Complement levels are usually normal or slightly decreased, compared with decreased levels in other inflammatory arthritides. ECGis done during the initial evaluation. Serum cardiac marker levels are obtained; normal cardiac troponin I levels exclude prominent myocardial damage. ECG abnormalities such as PR prolongation do not correlate with other evidence of carditis. Only 35% of children with ARF have a prolonged PR interval; higher-degree heart block may occur but is uncommon. Other ECG abnormalities may be due to pericarditis, enlargement of ventricles or atria, or arrhythmias. can detect evidence of carditis even in patients without apparent murmurs and is recommended for all patients with confirmed or suspected ARF. Echocardiography is also used to detect subclinical carditis in patients with apparently isolated Sydenham chorea and to monitor the status of patients with recurrences of carditis or chronic rheumatic heart disease. However, not all echocardiographic abnormalities represent rheumatic carditis; isolated trivial valvar regurgitation or trivial pericardial effusion may be a nonspecific finding. To maintain specificity, echocardiographic and Doppler results should meet the following criteria ( Diagnosis reference ) for acute rheumatic carditis: Doppler flow criteria: Pathologic mitral regurgitation: Must be seen in at least 2 views, and have a jet length ≥ 2 cm in at least 1 view, a peak velocity of > 3 m/second, and a pansystolic jet in at least 1 envelope Pathologic aortic regurgitation: Must be seen in at least 2 views, and have a jet length ≥ 1 cm in at least 1 view, a peak velocity of > 3 m/second, and a pandiastolic jet in at least 1 envelope Echocardiographic morphologic criteria: Pathologic mitral valve morphologic changes include annular dilation, chordal elongation or rupture with flail leaflet, anterior (or less commonly posterior) leaflet tip prolapse, or beading/nodularity of leaflet tips. Pathologic aortic valve morphologic changes include irregular or focal leaflet thickening, coaptation defect, restricted leaflet motion, or leaflet prolapse. Chest x-rays are not routinely done but can detect cardiomegaly, a common manifestation of carditis in ARF. Biopsy of a subcutaneous nodule can aid in early diagnosis, especially when other major clinical manifestations are absent. ESR and serum CRPare sensitive but not specific. The ESR is typically>60 mm/hour. CRP is typically > 30 mg/L (> 285.7 nmol/L) and often>70 mg/L (> 666.7 nmol/L); because it rises and falls faster than ESR, a normal CRP may confirm that inflammation is resolving in a patient with prolonged ESR elevation after acute symptoms have subsided. In the absence of carditis, ESR usually returns to normal within 3 months. Evidence of acute inflammation, including ESR, usually subsides within 5 months in uncomplicated carditis. The WBC count reaches 12,000 to 20,000/mcL (12 to 20 × 109/L) and may go higher with corticosteroid therapy. The differential diagnosis includes Juvenile Idiopathic Arthritis (JIA) (especially systemic JIA and, less so, polyarticular JIA), 1.Gewitz MH, Baltimore RS, Tani LY, et al: Revision of Jones criteria for the diagnosis of acute rheumatic fever in the era of Doppler echocardiography: A scientific statement from the American Heart Association.Circulation131:1806–1818, 2015. doi: 10.1161/CIR.0000000000000205 