RHEUMATIC FEVER /RHEUMATIC HEART

DISEASE

Acute , immunologically mediated, multisystem inflammatory disease.

Occurs 10 days to 6 weeks after an episode of group A streptococcal pharyngitis.

Affects usually children (5-15 yrs) but 20% cases can be seen in adults.

Active phase of RF may progress to chronic RHD. RF does not occur after a streptococcal inf at

other sites eg skin.

Is an important public health problem in poor socioeconomic localities

Incidence has < due to better living standards, rapid diagnosis, good drug therapy & unexplained < in virulence of gp A streptococci

Systems involved are:- Heart esp cardiac valves, endocardium.- Joints esp large ones (migratory polyarthritis).- Skin (erythema marginatum).- Subcutaneous nodules.- Neurological disorder called SYNDENHAM

CHOREA (involuntary purposeless rapid movements).

Morphology HEART LESIONS:- Acute RF: characterized by distinctive lesions called

ASCHOFF BODIES in the myocardial interstitium.- They are circumscribed lesions consisting of a central focus of

necrotic,swollen eosinophilic collagen surrounded by T-lymphocytes, occasional plasma cells & plump macrophages called Anitschkow cells (abundant cytoplasm central round to ovoid nuclei with chromatin disposed in a central, slender, wavy ribbon).

- also called caterpillar cells - pathognomonic for RF.- some large macrophages become multinucleated Aschoff

Giant Cells.

During acute RF, diffuse inflammation & Aschoff bodies may be found in all 3 layers of heart (PANCARDITIS)

PERICARDIAL LESIONS: Fibrinous or serofibrinous pericardial exudate

called “bread & butter” pericarditis. This generally resolves without any sequelae.

MYOCARDIAL LESIONS: - Myocarditis Scattered Aschoff bodies within the interstitial

connective tissue ENDOCARDIAL LESIONS: Simultaneous involvement of endocardium &

left sided cardiac valves by inflammatory foci causes fibrinoid necrosis of cusps or chordae tendinae.

Small 1-2 mm vegetations called “verruca” situated along the line of closure of the valves.

They are irregular & wart-like Cause little disturbance in cardiac function Formed due to precipitation of fibrin & collagen

degeneration at sites of closure Left atrium shows irregular, subendocardial

lesions called MacCallum plaques

PATHOGENESIS Acute RF is a hypersensitivity reaction

caused by gp A Streptococci Antibodies against M protein of certain

strains of streptococci cross-react with glycoprotein antigens in the heart, joints & other tissues

Streptococcal infection evokes an autoimmune response against self-antigens

Genetic suseptibility also plays a major role in pathogenesis of this disease

Group A streptococci elaborate the cytolytic toxins streptolysins S and O.

Streptolysin O induces persistently high antibody titers that provide a useful marker of group A streptococcal infection and its nonsuppurative complications (ASO Ab test).

Rheumatogenic strains often are encapsulated mucoid strains rich in M proteins and resistant to phagocytosis.

The presence of the M protein in the cell wall is the most important virulence factor for group A streptococcal infection in humans.

CHRONIC RHD

Characterized by organization of acute inflammation & fibrosis

Permanent valvular deformity (esp mitral valve) due to retraction & thickening of leaflets

Mitral & tricuspid valves show leaflet thickening, commissural fusion, shortening, thickening & fusion of tendinous cords

VALVULAR LESIONS of CH.RHD

Mitral valve alone is affected in 65-70% cases of RHD.

RHD is responsible for 99% cases of mitral stenosis

Concomitant involvement of mitral & aortic valve is seen in 25% cases

Less severe damage may also occur in the tricuspid & pulmonary valves

Fibrous bridging & calcification across valvular commissures creates “fish mouth” or “buttonhole” stenosis.

Mitral stenosis causes progressive left atrial dilatation, harbouring a mural thrombus in its appendage or along its wall.

Lungs show congestive changes ultimately leading to rt ventricular hypertrophy.

Left ventricle is essentially normal with isolated mitral stenosis

Microscopy (RHD) Diffuse & dense fibrosis. Neovascularization of valves. Aschoff bodies are replaced by fibrous

scar therefore not seen in autopsy specimens of ch CHD

Diagnosis of ARF

JONES CRITERIA:- Clinical features & Lab investigations

Major Criteria (JONES)

1. Migratory polyarthritis of large joints

2. Carditis

3. Subcutaneous nodules

4. Erythema marginatum of skin

5. Syndenham chorea

JONES (Major Criteria)

J =Joints (migratory polyarthritis). O=(imagine heart shape) Carditis. N=Nodules (s/c nodules), painless collections of

collagen fibres on back of wrists, front of knees. E= Erythema marginatum (long lasting rash that

begins on trunk or arms.) S= Syndenhams chorea ( rapid purposeless

movements of limbs & face.)

CANCER (Major Jones Criteria) C=Carditis A= Arthritis N=Nodules C=Chorea ER=ERythema marginatum.

Minor Criteria (clinical features & Lab investigations)Nonspecific signs & symptoms:1. Fever 2. Arthralgias - jt pain without swelling.3. Lab abn -↑ESR, ↑CRP, ↑WBC.4. ECG- prolonged PR interval.5. Previous rheumatic fever.6. Evidence of gpA Streptococcal inf:- + culture ↑ ASO titre

DIAGNOSIS Jones criteria:-

***TWO MAJOR MANIFESTATIONS

OR

***ONE MAJOR & TWO MINOR CRITERIA in order to establish the diagnosis.

Clinical features: arthritis & carditis - arthritis is more common in adults than

children -begins as migratory polyarthritis

accompanied with fever One large joint is involved after another

becomes painful & swollen for some days Subsides spontaneously Leaves no residual deformity

Carditis: pancarditis Pericardial friction rubs Weak heart sounds Tachycardia & arrhythmias New heart murmurs. other clinical features include epistaxis &

abdominal pain.

Myocarditis may cause cardiac dilatation leading to mitral valve insufficiency or even heart failure.

PROGNOSIS

In cases of primary attack is excellent with only 1% cases dying from fulminant RF

COMPLICATIONS RECURRENCES are liable to occur after

each subsequent pharnygeal attack with similar clinical manifestations.

CARDITIS TENDS TO MORE SEVERE in recurrent episodes.

EMBOLIZATION from mural thrombi within atria or their appendages.

INFECTIVE ENDOCARDITIS superimposed on deformed valves.

Ch rheumatic carditis does not cause clinical manifestations for years or even decades after the initial episode of RF

CARDIAC MURMURS CARDIAC HYPERTROPHY &

DILATATION HEART FAILURE ARRHYTHMIAS LIKE ATRIAL

FIBRILLATION

Treatment

Surgical repair by incising the diseased mitral stenotic valve commissures & replacement by prosthetic devices has greatly improved the outcome of this disease.

Rheumatic fever- vegetations (verrucae)

Acute Rheumatic Fever: small verrucous vegetations on line of closure of mitral valve

Rheumatic fever vegetations

Ch.rheumatic valvulitis affecting the mitral valve & dev due to organization & fibrosis of ac endocardial inflammation. Note the shortened & thickened

chordae tendinae

Chronic rheumatic scarring: fish mouth deformity of mitral valve

AORTIC STENOSIS (RHEUMATIC FEVER)

RHEUMATIC NODULES ON BACK

RHEUMATIC NODULES

Erythema marginatum

Ac rheumatic carditis: ASCHOFF NODULES best seen in myocardial interstitium & centered around

a b.v.

L/M: ASCHOFF NODULE COMPOSED OF GIANT CELLS & MONONUCLEAR CELLS

AC.RHEUMATIC CARDITIS SHOWING A PECULIAR CELL CALLED ANITSCHOW MYOCYTE :ELONGATED THIN CELL WITH A THIN ELONGATED NUCLEUS (CATERPILLAR CELL).

Aschoff nodule in myocardium

Rheumatic myocarditis (aschoff nodule)

ACUTE RH.HEART DISEASE

Fig 5-6. Rheumatic Heart Disease: A: In acute rheumatic heart disease. There is necrosis and an associated inflammatory reaction in the myocardial interstitium.

RH.HEART DISEASE

Fig 5-6. Rheumatic Heart Disease: B: The Aschoff body is pathognomonic for rheumatic heart disease and is composed of a necrotic focus infiltrated by mononuclear and multinucleated giant cells, Anitschkow cells.

RH.HEART DISEASE

Fig. 5-6. Rheumatic Heart Disease: C: Healed rheumatic valvulitis is characterized by blood vessels proliferation and an associated inflammatory reaction.