Pathology of Rheumatic Fever 2009

8/14/2019 Pathology of Rheumatic Fever 2009

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Rheumatic feverRheumatic fever


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RHEUMATIC FEVERIs immunologically mediated, multisysteminflammatory disease that occurs a few weeksfollowing an episode of group A hemolyticstreptococcal pharyngitis.-both sexes are equally affected between 5-

15 years


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The incidence and mortality rate of RF have declinedremarkably in many parts of the world over the past30 years, owing to improved socioeconomic conditions,and an unexplained decrease in the virulence of group

A streptococci. Nevertheless, in developing countries,and in many crowded, economically depressed urbanareas in the Western world, RF remains an importantpublic health problem.


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AETIOLOGYPredisposing factors:

1-Hereditarypredisposition

2-Cold climate, low socio-economic standards

overcrowding andmalnutritionrecurrent streptococcaltonsillitis

Exciting cause: abnormalimmune reaction.


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uresofacuterheumatic


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PATHOGENESIS -Group A strep pharyngeal infection precedes clinicalmanifestations of ARF by 2 - 6 weeks

-Antibodies made against group A strep cross-react

with human tissue because of molecular mimicry. heartvalve and brain share common antigenic sequences withGAS bacteria starting the formation of allergic granuloma.

-Only a minority of infected patients develop RF, suggesting

the role of genetic susceptibility


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PathogenesisMost important antigenic proteins in externallayer of cell wall M, T

and R proteins


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TISSUE REACTION

Characteristic lesion known as Aschoffs body.

Central area of necrosis.

Collection of chronic inflammatory cells withoccasional Aschoff giant cells.

Fate: Fibrosis.


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Normal myocarduim Aschoffbodies


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Aschoff body


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Clinical diagnosis:

The clinical diagnosis of acute rheumatic fever is madewhen two major or one major and two minor criteria -Jones Criteria, are met.The major clinical manifestations include - Carditis ,Erythema marginatum ,Migratory large joint arthritis ,

Sydenham chorea (a neurologic disorder with involuntarypurposeless, rapid movements),Subcutaneous nodules.

The minor manifestations include - arthralgia ; fever ;certain laboratory tests indicative of an inflammatoryprocess (Eg: , positive test for C-reactive protein,leukocytosis) and electrocardiographic changes


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Major manifestations Minor manifestations

Carditis Fever

Arthritis Arthralgia

Sydenhams chorea laboratory tests indicative of aninflammatory process

Erythema marginatum electrocardiographic changes

Subcutaneous nodules

Guidelines for the diagnosis of initial attack of rheumatic fevrer

Jones Criteria


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Subcutaneous nodules are rarely seen and whenpresent, they are usually associated with severecarditis. They are painless, firm, movable, measuringaround 0.5 to 2 cm. They are usually located overextensor surfaces of the joints, particularly knees,

wrists and elbows


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Erythema marginatumon the trunk, showingerythematous lesions with pale centers and roundedor serpiginous margins


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Acute rheumatic feverThe predominant clinical manifestations are those of carditis andarthritis

acute carditis: (pancarditis)includePericarditis ,myocarditis,endocarditis:During the acute stage, The myocarditis may cause cardiac dilationthat may evolve to functional mitral valve insufficiency or even heart

failure.but with chronic disease, endocarditis with permanent valvelesions are most serious and dangerous. The patholigical change of thevalve lead to its stenosis and or regurgitation.

Arthritis It typically begins with migratory arthritis accompanied byfever in which one large joint after another becomes painful and swollenfor a period of days and then subsides spontaneously, leaving no residual

disability.


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PATHOLOGYRheumatic carditis: Pancarditis1-Rheumatic Endocarditis

2-Rheumatic Myocarditis

3-Rheumatic pericarditis.


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RHEUMATIC ENDOCARDITIS

Valvular endocarditis: affects the valvular

endocardium especially arotic and mitral valve

Mural endocarditis: affects the mural endocardiumof the posterior wall of the left atruim


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Acute Rheumatic Valvulitis

Multipleepisodes of acute Rheumatic fever.Inflammation of the cardiac cusps with the formation of Aschoffs

nodules with edema results in swelling of the leaflets of the cusps,friction of their free borders.injury of the endotheliumthrombosis(vegetations(

-Acute phase subsides then fibrosis alters leaflet and cusp

structureresults in leaflet or cuspal thickening along valvularmargins of closure, commissural fusion and shortening, and thickeningand fusion of the tendinous cords..

Valves affected. Most often mitral valve alone .Then most oftenmitral and aortic together .Lastly aortic alone


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AcuteRheumaticValvulitisValve cusps are swollenand red

- Vegetations arefound near the freemargin of cusps( small, beaded, paleand adherent)

Mitral valve vegetations
http://www.pathology.vcu.edu/education/cardio/images/2e-d.jpg


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Mitral valve vegetationsRF

Vegetation fibrin


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Vegetation, fibrin,platelets


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RHEUMATIC MYOCARDITIS

Aschoff's bodies are seen in interstitial tissue ofthe myocardium and associated with interstitialedema and mild inflammation, sometimes

with muscle fiber necrosis.

- The condition is usually mild, but mayproduce left ventricular failure.

Rheumatic


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Rheumaticmyocarditis

Aschoff giant


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Aschoff giantcells


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RHEUMATIC PERICARDITISRheumatic fever is the commonest cause of sero-fibrinous pericarditis mainly at the heart base,

the pericardial sac is filled with serous fluidand fibrin is deposited on both visceral andparietal pericardium. Pericarditis heals byorganization (fibrosis) which can result in

Adhesions between the visceral and parietalpericardium. Separation of which producesbread and butter appearance.

Aschoffs' bodies may be seen.


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Serofibrinous pricarditis,

Serofibrinous pericarditis


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Serofibrinous pericarditis,


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Serofibrinous pericarditis,

Serofibrinous pricarditis fibrin


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Serofibrinous pricarditis, fibrinthreads


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Pericarditis, fibrin at the


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COMPLICATIONS OF RF

-Valvular lesions.

- Infective endocarditis

Heart failure


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Valvular damageHealing of acute valvular lesion by fibrosis with fusion

of the cusps result in inability of the valve to openproperly.

Stenosis

Healing of acute valvular lesion by fibrosis withcontraction of the cusps result in inability of the

valve to close properly.incompetence


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Stenotic mitral valve

seen from left atrium.Both commissures arefused; the cusps areseverely thickened.


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This view of the atrioventricular valves shows marked stenosis ofthe mitral valve, and less severe involvement of the tricuspidvalve..

Thickened mitral valve, fibrotic chordae tendinae
http://www.pathology.vcu.edu/education/cardio/images/2f-a.jpg


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Thickened mitral valve, fibrotic chordae tendinae


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Effect of MitralStenosis

On Heart

-Left atrium hypertrophiesand dilates and its pressure

increase. It leads topulmonary venoushypertension and oedema

-increased pulmonary

arterial pressure andpulmonary vascularresistance . Right ventricledilates from pressureoverload .. Right heart

failure develop


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Effect of Mitral Stenosis

On Heart

-Atrial fibrillation and thrombosis may occur.-Left ventricles protected by stenotic mitralvalve

-LV usually normal in size and contour

-


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Valvular damageMitral incompetance-may occur alone or associated

with mitral stenosis.

- Blood accumulates in the leftside of the heart hypertrophythen dilatation of both the leftventricle and atrium and then left

side heart failure.
http://en.wikipedia.org/wiki/File:Mitral_Regurgitation_scheme1.png


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Aortic Regurgitation

-the leaflets of thevalve do not fittogether properly lead

to left ventriculardilatation and failure


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Valvular damageAortic Stenosis-Fusion, thickening of the cusps leading to concentric left ventricularhypertrophy. Inadequate coronary perfusion lead to syncope and angina.Eventually. Left ventricular failure develop.


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INFECTIVE ENDOCARDITIS

-Infection of the endocardium (esp. heart valves) by amicrobiological agent, with the formation ofvegetations of fibrin, inflammatory cells, & bacteria

or other organisms.-Vegetations located most commonly on heart valves,

esp. aortic & mitral.

-Vegetation may produce emboli that produce infarctsin brain, kidney, myocardium, & other organs


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Vegetation of infective endocarditis


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Heart failure

Heart failure (HF) is a condition in whichthe heart is unable to provide the bodywith enough blood and nutrients to meetits metabolic needs. Heart failure is

usually caused by failure of the heart tofunction efficiently as a pump-It may be acute or chronic.-Chronic may be right or left sided or

total heart failure.

-Blood backs up causing congestion of neck veins and swelling ofextremities and internal organs


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Pathology of Rheumatic Fever 2009

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