“Rheumatic HEART disease”

“Rheumatic HEART disease” DR KIRAN H S YMC PATHOLOGY

Rheumatic fever (RF)

Definition • Etiopathogenesis • Morphological changes • Clinical featues • Complications

Etiopathogenesis • Immune responses • to group A streptococci, • which happen to cross-react with host tissues

CD4+ T cells produce cytokines that activate macrophages M proteins of streptococci

antibodies against the M proteins of certain strains of streptococci  cross-react with glycoprotein antigens in the heart, joints, and other tissues.

Evidence supporting the concept • onset of symptoms 2 to 3 weeks after infection and • the absence of streptococci from the lesions

The chronic sequelae • result from progressive fibrosis due to both • healing of the acute inflammatory lesions and • the turbulence induced by ongoing valvular deformities.

Rheumatic fever (RF) is an • acute, • immunologically mediated, • multisystem inflammatory disease • that occurs a few weeks following an episode of group A streptococcal pharyngitis

Acute rheumatic carditis • is a frequent manifestation during the active phase of RF and • may progress over time to • chronic rheumatic heart disease (RHD)

Morphology

Acute RF • focal inflammatory lesions are found in various tissues. • most distinctive within the heart, • where they are called Aschoff bodies

Aschoff bodies • foci of swollen eosinophilic collagen • surrounded by • lymphocytes (primarily T cells), • occasional plasma cells, and • plump macrophages called Anitschkow cells (pathognomonic for RF).

Anitschkow cells • macrophages • abundant cytoplasm • central round-to-ovoid nuclei • chromatin is disposed in a central, slender, wavy ribbon ( “caterpillar cells” ), • may become multinucleated • “caterpillar” shape longitudinally. • “owl-eye” appearance in cross-section

pancarditis • During acute RF • diffuse inflammation and Aschoff bodies • may be found in • any of the three layers of the heart, causing • pericarditis, • myocarditis, or • endocarditis

pericarditis • In the pericardium, the inflammation is accompanied by a • fibrinous or serofibrinous pericardial exudate, described as • a "bread-and-butter" pericarditis, • generally resolves without sequelae.

myocarditis • takes the form of • scattered Aschoff bodies within the interstitial connective tissue, • often perivascular

Inflammation of the endocardium and the left-sided valves Typically results in • fibrinoid necrosis • within the cusps • or • along the tendinous cords. • Overlying these necrotic foci are • small (1- to 2-mm) vegetations, • called verrucae • along the lines of closure.

These irregular, warty projections probably arise from • the precipitation of fibrin at sites of EROSION, • related to • underlying inflammation and • collagen degeneration • cause little disturbance in cardiac function

Other vegetative valve diseases

Regurgitant jets • may induce irregular Subendocardial thickenings called • MacCallum plaques, • usually in the left atrium.

Chronic RHD-Morphology • characterized by • organization of the acute inflammation and • subsequent fibrosis. • In particular, • the valvular leaflets become • thickened and • retracted, • causing permanent deformity

cardinal anatomic changes of the mitral (or tricuspid) valve are • leaflet thickening, • commissural fusion and shortening, and • thickening and fusion of the tendinous cords

Fibrous bridging across the valvularcommissures and calcification create “fish mouth” or “buttonhole” stenoses

Microscopy- Chronic RHD • there is diffuse fibrosis and • often neovascularization that • obliterate the originally layered and avascular leaflet architecture. • Aschoff bodies are replaced by fibrous scar • Fibrosis resulting from healed inflammation outside the valves is usually of no consequence

RHD • characterized principally by deforming fibrotic valvular disease • particularly mitral stenosis, • of which it is virtually the only cause • mitral valve alone  65% to 70% of cases • mitral and aortic  25% • Frequency • Mitral > aortic > tricuspid > pulmonic(only rarely affected)

left atrium progressively dilate right ventricular hypertrophy left ventricle is largely unaffected by isolated pure mitral stenosis. pulmonary vascular and parenchymal changes

Clinical Features • Major manifestations (1) migratory polyarthritis of the large joints (2) pancarditis (3) subcutaneous nodules (4) erythemamarginatum of the skin, and (5) Sydenham chorea, a neurologic disorder with involuntary rapid, purposeless movements.

minor manifestations • nonspecific signs and symptoms • Fever • Arthralgia • elevated blood levels of acute-phase reactants

diagnosis • established by the so-called Jones criteria • evidence of a preceding group A streptococcal infection, with the presence of • two of the major manifestations or • one major and two minor manifestations

Acute RF • typically appears • 10 days to 6 weeks after an episode of pharyngitis caused by group A streptococci • in about 3% of infected patients. • most often in children between ages 5 and 15, • but first attacks can occur in middle to later life.

Although pharyngeal cultures for streptococci are negative by the time the illness begins, • antibodies to one or more streptococcal enzymes, such as streptolysin O and DNase B, can be detected in the sera of most patients with RF • Evidence of a preceding group A streptococcal infection

Clinical features & complications related to acute carditis • pericardial friction rubs • weak heart sounds • tachycardia • arrhythmias. • Myocarditis may cause cardiac dilation can evolve to functional mitral valve insufficiency or even heart failure. • Approximately 1% of patients die from fulminant RF.

Arthritis • typically begins with migratory polyarthritis (accompanied by fever) in which • one large joint after another becomes painful and swollen for a period of days and • then subsides spontaneously, • leaving no residual disability.

After an initial attack • there is increasedvulnerability to reactivation of the disease with subsequent pharyngeal infections, and • the same manifestations are likely to appear with each recurrent attack. • Damage to the valves is cumulative

chronic RHD • Turbulence induced by ongoing valvular deformities  additional fibrosis. • Clinical manifestations • appear years or even decades after the initial episode of RF and • depend on which cardiac valves are involved.

Cardiac murmurs • Cardiac hypertrophy and dilation • Heart failure • Arrhythmias • (particularly atrial fibrillation in the setting of mitral stenosis) • Thromboembolic complications • Infective endocarditis.

Bacterial endocarditis • follows episodes of bacteremia • in persons with risk factors (e.g., during dental procedures). • The scarred valves of rheumatic heart disease provide an attractive environment for bacteria that would bypass a normal valve.

Mural thrombi • form in atrial or ventricular chambers • in 40% of patients with rheumatic valvular disease. • They give risetothromboemboli, • which can produce infarcts in various organs. Congestive heart failure • may complicate rheumatic disease • of both mitral and aortic valves. • cardiac hypertrophy and dilation

Arrhythmias • particularly atrial fibrillation • in the setting of mitral stenosis

The incidence and mortality rate of RF and RHD • Have declined remarkably in many parts of the world over the past century • Result of • improved socioeconomic conditions and • rapid diagnosis and treatment of streptococcal pharyngitis. • RHD remains an important public health problem in • developing countries • in many crowded, economically depressed urban areas in the Western world • affecting an estimated 15 million people. • Rheumatic fever only rarely follows infections by streptococci at other sites, such as the skin.

Definition • Etiopathogenesis • Morphological changes • Clinical featues • Complications

“Rheumatic HEART disease”