Rheumatic Heart Disease

 

Epidemiology and Etiology:

    • Rheumatic heard disease is cause of 99% of all mitral stenosis
    • Hypersensitivity reaction induced by group A streptococci (GAS)
    • Children 5-15y
    • Chronic rheumatic heart disease manifests later:
      • Years or decades after rheumatic fever

 

Common sites:

    • mitral valve virtually always involved in chronic rheumatic heart disease
    • mitral valve alone (65-70%)
    • mitral and aortic valves (25%)
    • similar but generally less severe changes in tricuspid and rarely in pulmonic valves

 

Gross features:

    • acute rheumatic fever (RF):
      • “bread-and-butter” pericarditis
        • fibrinous or serofibrinous pericardial exudates
      • 1-2mm vegetations on line of closure of left-sided valve leaflets
      • irregular thickenings in the left atrium (MacCallum plaques) (caused by regurgitant jets)
    • chronic rheumatic heart disease (RHD):
      • left-sided valve changes (“fish-mouth” or “buttonhole” stenoses):
        • leaflet thickening and shortening
        • commissural fusion
        • thickening and fusion of the tendinous cords
      • dilated left atrium
      • secondary cor pulmonale over time

 

Histologic features:

    • Acute rheumatic fever (RF):
      • Heart:
        • Aschoff bodies in any layer of the heart (pancarditis):
          • Foci of swollen eosinophilic collagen surrounded by inflammatory cells:
            • lymphocytes (primarily T cells)
            • occasional plasma cells
            • plump macrophages (Anitschkow cells – pathognomonic for RF)
              • abundant cytoplasm
              • central round-to-ovoid nuclei
              • chromatin in a central, slender, wavy ribbon
              • some are multinucleated
          • often perivascular in myocardium
        • fibrinoid necrosis within the cusps of the left-sided valves or along the tendinous cords
    • chronic rheumatic heart disease:
      • diffuse fibrosis of valves
      • neovascularization of leaflet (normally avascular)
      • no Aschoff bodies (replaced by fibrous scar)

 

Immunophenotype:

Marker:

Sensitivity:

Specificity:

 

 

 

 

Molecular features:

    •  

 

Other features:

    • serum antibodies present in most patients:
      • streptolysin O
      • DNAse B
    • rheumatic fever occurs 10d to 6wk following an episode of GAS pharyngitis (3%)
    • Jones criteria:
      • Preceding GAS infection
      • 2 major or 1 major and 2 minor manifestations
      • major manifestations:
        • migratory polyarthritis of large joints
        • carditis
        • subcutaneous nodules
        • erythema marginatum in the skin
        • Sydenham chorea
      • Minor manifestations:
        • Nonspecific signs and symptoms
        • Fever
        • Arthralgia
        • Elevated acute phase reactants in blood
    • Recurs with subsequent pharyngeal infections

 

References:

    • Robbins 2005