Rheumatic heart disease

Transcription

1 Rheumatic heart disease

2 What will we discuss today? Etiology and epidemiology of rheumatic heart disease Pathogenesis of rheumatic heart disease Morphological changes in rheumatic heart disease Clinical manifestations

3 Etiology & overview Group A streptococcus Pharyngitis (mainly but not only) Rheumatic fever (RF) acute immunologically mediated multisystem disease The main cardiac abnormalities in this condition are in..??? a common manifestation of active RF is: acute rheumatic carditis may progress to chronic rheumatic heart disease = RHD

4 Epidemiology Mortality & incidence of RF and RHD have significantly declined in many parts of the world.why?

5 Pathogenesis Acute RF results from: immune reaction cross-reactivity Antibodies and CD4+ T cells damage heart tissue Antigens: M protein and cardiac self antigens (cross-reactivity)

6 Pathogenesis, cont d They recognize streptococcal M proteins (cross-react with cardiac self antigens) by T cell receptors (TCRs) T cells (mainly CD4+) stimulate B cells to secrete: Antibodies Activation of complement Opsonization -Cytokine release -Activation of macrophages in Aschoff bodies

7 Morphology In acute rheumatic fever: foci of inflammation in various tissues especially in the heart we find: Aschoff bodies = T cells + occasional plasma cells + activated macrophages Pathognomonic for RF = Anitschkow cells Visit For references Visit for references -plump -abundant cytoplasm -central round-to-ovoid nuclei occasionally binucleate -chromatin condenses into a central, slender, wavy ribbon so they are called: caterpillar cells

8 Morphology of acute RF, cont d Diffuse inflammation and Aschoff bodies may be found in any of the three layers of the heart pericarditis, myocarditis or endocarditis pancarditis little disturbance in cardiac function Mainly: fibrinous exudate self-limited Mainly: scattered Aschoff bodies in the interstitium = valvular involvement: fibrinoid necrosis and fibrin deposition along the lines of closure verrucae (vegetations)

9 Acute on top of chronic RHD an example Small vegetations (1-2 mm) Elsevier. Kumar et al. Robbins basic pathology 9th

10 Morphology of chronic rheumatic heart disease Organization scarring Aschoff bodies are replaced by fibrous scars also there is calcification Valve cusps & leaflets permanently thickened and retracted especially: mitral valve Elsevier. Kumar et al. Robbins basic pathology 9th (E, From Schoen FJ, St John-Sutton M: Contemporary issues in the pathology of valvular heart disease. Hum Pathol 18:568, 1967.)

11 Mitral stenosis in chronic RHD

12 Clinical notes, acute RF Mainly children carditis 20%: in adults arthritis more < 1% mortality In all ages: 2-3 weeks after streptococcal infection: fever + migratory polyarthritis then spontaneous resolution then: pericarditis, myocarditis or endocarditis or pancarditis Pericardial friction rub arrhythmias Can be so severe to cause mitral insufficiency and congestive heart failure

13 Clinical notes, acute RF cont d Cultures are negative Serum antibodies against one or more streptococcal antigens (streptolysin O, DNAse..etc.) are positive For diagnosis: serologic evidence of previous streptococcal infection + 2 or more of the major Jones criteria (1) carditis (2) migratory polyarthritis of large joints *Minor criteria: -fever -arthralgias -ECG changes -elevated acute phase reactants (3) subcutaneous nodules (4) erythema marginatum skin rashes (5) Sydenham chorea (also called St. Vitus dance)

14 Clinical notes, chronic RHD Valvular stenosis and regurgitation predominantly stenosis 70%: mitral alone 25%: mitral + aortic tricuspid much less frequently pulmonic almost always spared with time left atrial dilation and atrial fibrillation mural thrombus with time a picture similar to left sided heart failure followed by rt. sided failure What about left ventricle??

15 Clinical notes, chronic RHD Recurrent attacks with recurrent streptococcal infections cumulative damage Chronic disease after years/decades Scarred and deformed valves are more susceptible to infective endocarditis

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