Fig. 11.1
Posteroanterior radiograph in a young adult patient with acute rheumatic heart disease shows dilatation of the left atrial appendage (black arrow), creating a broad bump along the lateral margin of the heart below the level of the pulmonary artery (white arrow). Enlargement of the left atrium from mitral stenosis often causes the atrial appendage to protrude
In patients with chronic RHD (Fig. 11.2), radiography can show valve calcification (especially the mitral or aortic valves) and left atrial enlargement with mitral regurgitation or stenosis.
Fig. 11.2
Anteroposterior radiograph in a patient with a history of rheumatic heart disease shows postoperative changes from replacement of the aortic valve (white arrow) and mitral valve (black arrow). The aortic and mitral valves are the most commonly involved in rheumatic heart disease
11.2.2 ECG Findings
Atrial fibrillation is the most common ECG finding. Conduction delays or hypertrophy also may be identified. Prolongation of the PR interval serves as a useful minor criterion and a clinically helpful clue.
11.2.3 CT Findings
CT scans are useful to assess cardiac anatomy, valvular calcifications , and function. Valvular thickening may be seen with gated cardiac CT (Fig. 11.3).
Fig. 11.3
Axial (a) and sagittal (b) images from a cardiac CTA in a patient with rheumatic heart disease shows nodular thickening of the aortic valve (arrows)
11.2.4 MRI Findings
MRI is also useful to assess cardiac anatomy and function; it quantitates the degree of valve insufficiency or stenosis (regurgitant fraction). Cine gradient-refocused echo (GRE) imaging may be helpful to assess valves for thickening and stenosis.
11.2.5 Ultrasonographic Findings
In patients with ARF, ultrasonography may be useful to quantitate the degree of mitral insufficiency and left ventricular function.
In chronic RHD , it shows progression of valve stenosis with thickened and possibly calcified leaflets and may show fusion of commissures and chordae. Echocardiography has been shown to be helpful in preventing overdiagnosis by excluding physiologic flow murmurs and undetected congenital heart disease [5]. Various types of studies provide different information:
M-mode: Dimensions of the left atrium and aorta; left ventricular dimensions in systole and diastole [1]
Two-dimensional (2D) echocardiogram: Apposition of the mitral valve leaflets during systole; thickened valve cusps with poor leaflet separation in diastole; decreased or increased mobility of the valves; chordal tears to mitral leaflets; pericardial effusion; enlarged left atrium; atrial thrombus [1]
Color Doppler: Establishment of mitral, aortic, and tricuspid regurgitation; differentiation between pathological and physiological regurgitation [1]
Cardiac scanning scintigraphy: A reliable method of distinguishing acute from chronic, inactive RHD ; follow-up of active carditis.
11.2.6 Imaging Recommendations
Doppler echocardiography is more sensitive than clinical examination alone in detecting valvular lesions; it has been shown to enable a 46.9 % higher level of detection of carditis [1]. This detection is particularly important because a longer period of prophylaxis is required for patients with proven carditis and for those with more than mild permanent valvular damage [1].
11.3 Differential Diagnosis
The differential diagnosis of ARF includes a long list of conditions:
Juvenile idiopathic arthritis (JIA)
Systemic lupus erythematosus
Septic arthritis
Kawasaki disease (usually ages 6 months–5 years)
Viral or other forms of cardiomyopathy
Leukemias
Vasculitis (Henoch–Schönlein purpura [HSP])
Drug reactions or serum sickness
CNS tumors (can mimic chorea)
Infective endocarditis
Myocarditis
Post-streptococcal reactive arthritis (arthritis not typical of ARF, but with recent streptococcal infection [2])
Sickle cell disease
Gonococcal arthritis
Tuberculosis
Lyme disease
11.4 Pathology
11.4.1 Etiology
ARF is believed to be an immunologically mediated delayed sequela of group A streptococcal infection. Most patients with ARF have elevated titers of antistreptococcal antibodies. Antigenic mimicry has been proposed as the triggering factor: Antibodies directed against streptococcal M proteins have been shown to cross-react with human tissues, such as heart valves, myosin and tropomyosin, brain proteins, synovial tissue, and cartilage [5].
11.4.2 Demographics
ARF occurs in about 3 % of patients infected with group A streptococcus. The incidence has declined markedly in developed countries over the past century, owing to improved socioeconomic conditions and rapid diagnosis and treatment of strep pharyngitis. The World Health Organization (WHO) estimates that 500,000 individuals acquire ARF each year, with 97 % of those in developing countries, where chronic RHD remains an important public health problem [3]. A resurgence in cases of group A beta-hemolytic strep over the past 10 years has increased concerns about ARF.
ARF occurs most often in children between the ages of 5 and 15, with recurrent attacks most frequent in adolescence [2].
ARF occurs equally in males and females, but RHD is more common in females [4], and they carry a worse prognosis. No association with ethnic origin has been found.
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
